Low-attenuation Mass Research Articles

CPC10 An unusual case of bilateral periorbital lesions

Abstract A 45-year-old man was referred to the dermatology department for a 5–10-year history of enlarging periorbital xanthelasma-like lesions with a non-significant lipid profile. The periorbital lesions episodically and spontaneously became swollen and were associated with a throbbing sensation. After exercise and minimal motion, haemorrhage into the lesions occurred. Clinical examination revealed multiple coalescing, symmetrical, thick, yellow plaques and nodules with red–brown areas of discoloration associated with eyelid telangiectasia. His past medical history included hiatus hernia, lipoma and Osgood-Schlatter disease of the knee. The differential diagnosis included adult-onset xanthelasma, necrobiotic xanthogranuloma and amyloidosis. Punch biopsy of the lesions showed histological features consistent with a xanthogranuloma. Owing to the association of this entity with underlying haematological malignancy, computed tomography was performed, which revealed a subtle 33 × 70 mm low-attenuating mass within the posterolateral aspect of the right iliacus muscle. On further radiological investigation, including magnetic resonance imaging (MRI) and positron emission tomography, an avid, nonaggressive right iliac bone lesion and nonavid bilateral, symmetrical metaphyseal and diaphyseal sclerosis involving both distal femur and proximal tibia were seen. Previous MRI of his knee, performed 3 years earlier following a fall, was reviewed and found to show an incidental signal abnormality in his distal femur. Tissue from the periocular xanthogranuloma was positive for the BRAF V600E mutation and tissue from biopsy of the right iliac crest was consistent with focal osteosclerosis. Owing to the histopathological, clinical and radiological features, a diagnosis of Erdheim–Chester disease (ECD) was established. As a result, the haematology team initiated the patient on a reducing dose of oral prednisolone with long-term methotrexate (15 mg weekly). This led to an improvement in appearance of the periorbital lesions. The differential diagnosis for periocular xanthogranuloma includes adult-onset xanthogranulomas and adult-onset asthma with periocular xanthogranuloma, necrobiotic xanthogranuloma and ECD. ECD is a rare form of non-Langerhans cell histiocytosis that is highly associated with BRAF V600E and other mitogen-activated protein kinase pathway mutations (Diamond EL, Durham BH, Haroche J et al. Diverse and targetable kinase alterations drive histiocytic neoplasms. Cancer Discov 2016; 6:154–65). The clinical course of ECD is generally aggressive, but it can vary from indolent disease to fatal multiorgan failure. Although ECD can have multiorgan involvement, approximately 25% of these patients have cutaneous manifestations (Kobic A, Shah KK, Schmitt AR et al. Erdheim-Chester disease: expanding the spectrum of cutaneous manifestations. Br J Dermatol 2020; 182:405–9). This case highlights the importance of considering ECD when faced with atypical periorbital lesions as these lesions can mimic common benign xanthelasma.

Prevalence of malignant or possibly malignant renal masses among homogeneous low-attenuation masses that are too small to characterize at computed tomography.

Homogeneous low-attenuation renal masses that are too small to characterize (tstc) are considered clinically insignificant; however, based primarily on expert opinion. To determine the prevalence of malignant or possibly malignant masses among homogeneous low-attenuation renal masses that are tstc. This retrospective cross-sectional study evaluated 75 patients with 104 tstc who underwent renal CT and MRI between Jan 2016 and Jul 2022. Low-attenuation renal masses measuring < 1cm in size were identified and, independently evaluated by two blinded radiologists measuring attenuation (Hounsfield Units, HU) at non-contrast enhanced CT (NECT) and nephrographic phase contrast-enhanced (CE)-CT when possible. Reference standard for benign cyst was MRI and for other renal masses was pathology or MRI showing enhancement. Average tstc size was 6 ± 2 (range 2-10) mm. Considering only incidental tstc (CT performed for another reason), 100% (98/98, 95%CI 96-100%) tstc were benign. Overall, considering both incidental and tstc referred for further characterization, there were 94% (98/104; 95% Confidence Intervals [CIs] 88-98%) benign cysts and 6% (6/104; 95%CI 2-12%) other masses (1 Bosniak 2F cystic mass, 2 probable renal cell carcinoma (RCC), three metastases). Pseudoenhancement, attenuation change > 10 HU or > 20 HU, was present in 29% (15/59) and 12% (7/59) benign cysts. All six other masses enhanced by > 20 HU. CECT threshold of ≤ 30 HU correctly classified 62% of benign cysts (61/98). All six other masses measured > 30 HU at CECT. The prevalence of malignant or possibly malignant renal masses among homogeneous low-attenuation too small to characterize masses among incidental tstc masses is near zero. Attenuation measurements misclassify a substantial proportion of these cysts, likely due to their small size.

Multimodal imaging findings of intrahepatic cholangiocarcinoma arising from a biliary adenofibroma: a case report with radiological–pathological correlation

PurposeBiliary adenofibroma is a solid microcystic epithelial neoplasm in the liver, comprising microcystic and tubuloacinar glandular tissues lined by a non-mucin secreting biliary epithelium and supported by a fibrous stroma. It is an extremely rare benign tumor with potential for malignant transformation. Herein, we report the case of a 64-year-old woman diagnosed with intrahepatic cholangiocarcinoma arising from biliary adenofibroma.MethodsImaging studies revealed a tumor of 50 mm diameter, consisting of two components in S1 of the liver. The ventral portion of the tumor showed an ill-defined mass with early peripheral and gradual centripetal enhancement invading to the middle hepatic vein on computed tomography (CT), diffusion restriction on magnetic resonance images, and high fluorine-18-2-deoxy-d-glucose (FDG) uptake on positron emission tomography, like conventional intrahepatic cholangiocarcinoma. The dorsal portion showed a well-defined and low-attenuated mass with heterogeneous early enhancement and partial wash-out on CT, marked hyperintensity on heavily T2-weighted images, and low FDG uptake. The patient subsequently underwent extended left hepatectomy.ResultsPathologically, the former was diagnosed as cholangiocarcinoma and the latter as biliary adenofibroma. We discuss the radiological-pathological correlation of the tumor with a literature review.ConclusionPreoperative diagnosis of biliary adenofibroma is extremely challenging; however, clinically, it is crucial not to miss the presence of malignant findings.Graphical abstract

Evaluation of class II cystic renal masses proposed in Bosniak classification version 2019: a systematic review of supporting evidence.

The Bosniak classification of cystic renal masses version 2019 (v.2019) includes an expanded number of types of masses in class II; such masses are considered benign in clinical practice. Data supporting these additions have not been well-documented. We aim to determine the proportion of malignant or probably malignant renal masses among the types added to Bosniak v.2019 class II. Multiple databases were searched for studies evaluating the proportion of malignant or probably malignant renal masses among new Bosniak v.2019 class II types, four for CT and two for MRI.Risk of bias and applicability was assessed using the QUADAS-2 tool. Ten studies (2068 renal masses) met inclusion criteria. Among the four added class II types at CT, the proportion of malignancy among (1) 'homogeneous hyperattenuating (≥ 70 HU) masses at unenhanced CT' was 0% (0/32) in three studies; (2) 'homogeneous masses - 9 to 20 HU at unenhanced CT' was 0% (0/1454) in two studies, and (3) 'homogeneous masses 21 to 30 HU at portal-venous phase CT' was 0% (0/454) in four studies. Masses that are homogeneous, have low attenuation, and are too small to characterize on CT had no supportive evidence. Among the two added class II types at MRI, the proportion of malignancy among (1) 'homogeneous masses markedly hyperintense at unenhanced T2-weighted MR imaging (similar to CSF) was 0% (0/72) in one study, and (2) 'homogeneous masses markedly hyperintense at T1-weighted MR imaging (~ 2.5 × renal parenchyma signal intensity)' was 0% (0/32) and 5% (2/37) in two studies. Nine studies were at risk of bias within at least one QUADAS-2 domain. The addition of six types of cystic renal masses to Class II in the Bosniak v.2019 proposal may be justified but based on limited evidence, with no evidence for 'homogeneous low attenuation masses that are too small to characterize' on CT, and thus considering them benign is in part based on expert opinion. Protocol Registration: PROSERO CRD42020196408.

Heterotopic Ossifications of the Forearm: A Cause of Post-Traumatic Loss of Pronation-Supination

HO is defined by the development of ectopic mature bone within nonosseous tissues. It is a well-described phenomenon that complicates forearm fractures, especially when there is an open fracture, a significant soft tissue injury, and associated neural axis or thermal injury. HO mainly forms near metal hardware and may lead to the formation of radio-ulnar synostosis. CT is superior to plain radiographs, as it identifies the ectopic bone earlier, defines its exact localization, and helps planning the surgical intervention. Radiologic features are variable; in the early stage, CT shows a low-attenuation mass with indistinct surroundings. As the ossification process progresses, zones of mineralization are visible before leading to the formation of mature cortical bone at the periphery (Figure 1 and 2: arrows). Hastings classification describes 5 classes according to how HO affects the forearm range of motion.

A rare case of accessory liver lobe torsion in a pediatric patient who showed recurrent epigastralgia and who was treated by elective laparoscopic resection

BackgroundAccessory liver lobe (ALL) is a rare liver malformation. An ALL develops due to malformation of the endodermal caudal foregut and segmentation of the hepatic bud in the third week of gestation. Most ALLs are asymptomatic and are detected incidentally during abdominal surgery. The incidence of ALL is < 1% in patients who undergo abdominal surgery. However, some ALLs twist and cause acute abdomen. We experienced a pediatric case of ALL torsion in a patient who underwent elective laparoscopic surgery.Case presentationThe 5-year-old girl had a 3-month history of epigastralgia and vomiting, which occurred every 2 weeks. Abdominal ultrasonography with color Doppler imaging revealed an 11.8 × 13.6 mm nonvascular lesion with mixed echogenicity near the round ligament of the liver. Enhanced computed tomography confirmed a 14 × 16 × 20 mm low-attenuation mass surrounded by a hyperdense line and disproportionate fat stranding on the right side of the round ligament of the liver. There was no ascites or hemorrhage. These findings suggested an abscess of the round ligament of the liver. Her symptoms improved with the administration of oral antibiotics; thus, we planned to perform elective exploratory laparoscopy and subsequent resection. Two trocars (5 mm) were inserted through a multichannel port device at the umbilicus and one trocar (3 mm) was inserted at the right lateral abdomen. Upon observation of the abdominal cavity, the omentum was observed adhering to the round ligament of the liver. Macroscopic observation revealed no apparent mass lesions. We performed adhesiolysis of the omentum from the round ligament of the liver using a vessel sealing system. We performed resection at the site at which adhesion had formed between the round ligament of the liver with the surrounding tissue using a vessel sealing system and the resected specimen was extracted through the umbilical wound. The postoperative course was uneventful. A pathological examination revealed necrotic liver tissue. The resected tissue was founded to be an ALL with ischemic change.ConclusionsThe recurrent abdominal pain was induced by torsion of the ALL. Pediatric surgeons should consider ALL torsion as a differential diagnosis for epigastralgia of unknown etiology.

Well-differentiated Spindle Cell Liposarcoma of the Larynx: A Rare Case Report and Review of Literature

Liposarcoma of the larynx is a rare entity. Well-differentiated spindle cell liposarcoma of the larynx has not been yet reported in the literature. We report the first case of well-differentiated spindle cell liposarcoma of the larynx on a 59-year-old male who presented with change of voice and phlegmy cough for several months. Laryngoscopy revealed a mucosal covered pedunculated mass on the supraglottis. Computerized tomography (CT) scan showed a low-attenuation mass causing moderate narrowing of the airway. The lesion was excised. Grossly, a 4.2 cm ovoid, solid and soft mass with homogeneously white-gray and rubbery cut surface was identified. Microscopic examination revealed a well-demarcated neoplasm composed of predominantly atypical and pleomorphic spindle cells distributed in collagenous stroma, with admixed adipocytes showing variation in cell size and rare lipoblasts. Immunohistochemical stains showed that the spindle cells were positive for MDM2, CDK4, and CD34. Overall, the histology and immunoprofile are consistent with a well-differentiated liposarcoma, spindle cell type. Due to the positive resection margin, the patient subsequently received endoscopic local re-excision with a carbon dioxide laser. He did well at 4 months after primary excision. This case illustrates that while well-differentiated spindle cell liposarcoma rarely occurs in the larynx, it should be considered in the differential diagnosis of patients with laryngeal lesions. A panel of immunohistochemistry markers including MDM2, CDK4 and CD34 is helpful to render accurate diagnosis. Wide excision with long-term follow-up is necessary for this rare variant of liposarcoma.

S2097 Pseudomyxoma Peritonei Presenting with Extrinsic Compression on Esophagogastroduodenoscopy and Colonoscopy

INTRODUCTION: Pseudomyxoma peritonei (PMP) is a rare disease characterized by mucinous ascites, classically originating from a ruptured low-grade appendiceal mucocele. We present a case of PMP identified because of signs of extrinsic compression on esophagogastroduodenoscopy (EGD) and colonoscopy. CASE DESCRIPTION/METHODS: A 66-year-old male presented for screening colonoscopy and EGD. His medical history was significant for renal calculi and recurrent acid reflux resistant to medical therapy. He denied weight gain or abdominal distension. A colonoscopy performed six years prior identified a single 3 mm tubular adenoma, diverticulosis, and internal hemorrhoids. Colonoscopy revealed sigmoid diverticulosis, a benign stricture in the recto-sigmoid colon, and a large, extrinsic-appearing mass in the descending colon (Figure 1). EGD revealed LA Grade C reflux esophagitis, a hiatal hernia, gastritis, one large non-bleeding duodenal ulcer with a clean ulcer base, and possible extrinsic compression in the gastric body (Figure 2). A CT Abdomen/Pelvis with contrast was obtained to further characterize this apparent extrinsic compression, which revealed diffuse low-density masses and ascites distending the peritoneal cavity with scalloped appearance of the liver and spleen. He was referred to surgical oncology and underwent a diagnostic laparoscopy with peritoneal biopsies that revealed extensive mucin and fibrin deposits, consistent with PMP. He underwent cytoreduction, right hemicolectomy, and hyperthermic intraperitoneal chemotherapy (HIPEC). Surgical pathology showed low grade mucinous carcinoma peritonei and the appendix showed a low-grade mucinous neoplasm. Repeat CT Abdomen/Pelvis with contrast revealed significantly improved peritoneal carcinomatosis and multiloculated, multiseptated, low attenuation masses throughout the abdomen. CEA was 58.3 at five months post-operative from 159.6 preoperatively. Seven months post-operatively the patient was doing well without findings concerning for recurrent disease. DISCUSSION: The incidence of PMP is estimated to be 1-3 per million per year. The growth of appendiceal mucinous tumors is indolent, and they are frequently diagnosed incidentally during evaluation for other conditions. They are classically identified on colonoscopy as an abnormal appearing appendiceal orifice (“volcano sign”) atop a “mound” of normal-appearing mucosa. This case highlights the importance of considering extraluminal etiologies for unexpected findings on endoscopy.Figure 1.: Extrinsic-appearing mass in the descending colon.Figure 2.: Possible gastric mass or extrinsic compression in the gastric body.Figure 3.: CT Abdomen/Pelvis with oral and IV contrast showing diffuse low-density masses and ascites, distending the peritoneal cavity with scalloped appearance of the liver.

BRONCHOGENIC CYST: A TALE OF THE THIRD RECURRENCE

SESSION TITLE: Medical Student/Resident Cardiothoracic Surgery Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Bronchogenic cysts (BCs) are singular congenital variances that surface early from anomalous budding of the maturing respiratory system between the 26th and 40th day of gestation (1). Most BCs are asymptomatic until they compress the surrounding structures. BCs are commonly seen in the mediastinum or intrapulmonary; with a previously reported prevalence of 1 per 42,000 and 1 per 68,000 admissions. They account for 50% to 60% of all mediastinal cysts. If incomplete resected, there is very high recurrence rate (2). We report a patient with second recurrence of mediastinal BC noted 18 years after initial drainage without resection. CASE PRESENTATION: A 57-year-old female with history of biopsy-proven BC with mediastinoscopy drainage followed by first recurrence treated with thoracoscopic drainage. Symptoms at presentation included three days of chest pain radiating between the scapula, associated with shortness of breath, low grade fever, and a dry cough. Vital signs were stable and lab-work was remarkable for WBC of 15.03 K/mm3 with 1% immature granulocytes. Chest x-ray showed a right paratracheal soft tissue density measuring 4.5 cm. Chest CT showed a large low-attenuation mass measuring 8 x 4.8 cm in the mediastinum region with 23 Hounsfield unit density (Image 1,2). Patient underwent video-assisted thoracoscopy converted to right thoracotomy for incision and drainage with sclerotherapy of the BC. Biopsy showed benign fibrous tissue with respiratory epithelium consistent with BC without atypia (Image 3). No growth was appreciated on stain and culture. Serial chest x-rays prior to discharge showed resolution of the soft tissue density. Improvement of respiratory symptoms upon surgery and treatment of community-acquired pneumonia with Rocephin 1gm IV QD and Azithromycin 500mg IV QD for five days. DISCUSSION: With the help of this case report we hope to shed light on the fact that symptomatic cysts should be resected either by thoracotomy or via video-assisted thoracoscopy (VAT) regardless of patient age, unless surgical risks are unacceptably high, as in our patient due to proximity of prominent vessels (3). Although many asymptomatic cases have been reported, a number of complications with BCs have been described, with infection being the most common followed by respiratory obstruction. While there has been a recent rise in the use of thoracoscopic techniques for resection of bronchogenic cysts in adults, one should not forget about patients with high surgical risks. The benefits of thoracoscopy drainage are decreased scarring, reduced pain, and shorter hospitalization (4). CONCLUSIONS: If incomplete resection or drainage is done, as seen in this patient, then residual mucosa should be treated by toxic agents or electrocautery (5). We propose serial imaging to monitor for recurrence when incomplete resection or drainage is done, as no current guidelines are present. Reference #1: 1) Reichelt O, Grieser T, Wunderlich H, Möller A, Schubert J. Bronchogenic cyst. A rare differential diagnosis of retroperitoneal tumors. Urol Int. 2000;64(4):216-219. Reference #2: 2) Limaïem F, Ayadi-Kaddour A, Djilani H, Kilani T, El Mezni F. Pulmonary and mediastinal bronchogenic cysts: a clinicopathologic study of 33 cases. Lung. 2008;186(1):55-61. Reference #3: 3) McAdams HP, Kirejczyk WM, Rosado-de-Christenson ML, Matsumoto S. Bronchogenic cyst: imaging features with clinical and histopathologic correlation. Radiology. 2000;217(2):441-446. 4) Lee DH, Park CK, Kum DY, Kim JB, Hwang I. Clinical characteristics and management of intrathoracic bronchogenic cysts: a single center experience. Korean J Thorac Cardiovasc Surg. 2011;44(4):279-284. [5] Rice DC, Putnam JB. Recurrent bronchogenic cyst causing recurrent laryngeal nerve palsy. Eur J Cardiothorac Surg 2002;21:561–3. DISCLOSURES: No relevant relationships by Loui Abdelghani, source=Web Response No relevant relationships by Hesham Afify, source=Web Response No relevant relationships by George Alvarez, source=Web Response No relevant relationships by Manuel Carrazana, source=Web Response No relevant relationships by Maria Wallis-Crespo, source=Web Response

S2756 Hepatoblastoma in a Patient With Goldenhar Syndrome

INTRODUCTION: Goldenhar Syndrome (GS) is a congenital defect characterized by the underdevelopment of the ears, soft palate, lip, and mandible. Only two cases have been reported in literature suggesting an association between hepatoblastoma and GS. Barton and Keller described an 8-year-old girl with GS and congenital absence of portal vein, who was found to have neoplastic invasion and hepatoblastoma on CT scan. Corona-Rivera et al, reported a case of hepatoblastoma in a patient with GS who was born to a diabetic mother. The underlying cause for this congenital syndrome is still poorly understood and its association with hepatic anomalies including hepatoblastoma is still unknown. We describe a 2-year-old girl with Goldenhar Syndrome diagnosed with hepatoblastoma after experiencing abdominal pain and constipation. CASE DESCRIPTION/METHODS: A 2-year old girl with diagnosis of Goldenhar syndrome based on physical exam findings of small bilateral ear tags, coloboma of the right upper eyelid, bilateral temporal lipodermoids, right limbal dermoid and mild ptosis of the right eye was brought to her pediatrician due to abdominal pain and constipation. CT scan of the abdomen showed hepatomegaly with heterogenous attenuation and calcified, low-attenuation mass components. Beta-human chorionic gonadotropin was slightly elevated and alpha fetoprotein was significantly elevated at 115,000 ng/mL. Liver biopsy results were positive for epithelial hepatoblastoma with fetal and embryonal patterns. After chemotherapy failed to shrink the tumor, the patient received a successful liver transplant. DISCUSSION: To our knowledge this is the third case reported in literature of a patient with GS and hepatoblastoma. Commonly, patients with hepatoblastoma presents with no symptoms. However, the two previously reported cases and our case presented with severe constipation and abdominal pain. This may suggest a predisposition to this atypical presentation in patients with GS. The mechanism for this hypothesis is unknown and more studies would need to be conducted to confirm the association. Findings from this case can further support the argument that a relation exists between these two different entities. Additionally, there are no current recommendations regarding appropriate surveillance for liver neoplasm in patients with diagnosis of GS. We believe that new guidelines and diagnostic studies will become more widely available as the associations between hepatoblastoma and Goldenhar syndrome are established.Figure 1.: H&E at 40×, showing hepatoblastoma on liver biopsy.Figure 2.: Hepatoblastoma positive for Hep Par-1 at 20× on liver biopsy.Figure 3.: CT scan showing hepatomegaly with heterogenous attenuation and calcified, low-attenuation mass components.

SAT-334 A Genetic Cause of Primary Hyperparathyroidism

Background: Primary hyperparathyroidism is a relatively common endocrine condition, affecting up to 7 out of every 1000 adults. Median age of onset is during the sixth decade of life. When present in younger patients primary hyperparathyroidism may indicate an underlying genetic cause. Case: A 23-year-old woman is referred for evaluation of hypercalcemia that was found on labs drawn after surgery for bilateral ovarian cyst removal. At the time of presentation she felt well and was without complaint. Her medical history is otherwise unremarkable. Her family history includes multiple family members with nephrolithiasis. Physical exam revealed a well appearing Caucasian woman without a palpable neck mass. Laboratory results showed: serum calcium 11.7 mg/dL (ref 8.4–10.2), ionized calcium 1.44 mmol/L (ref 1.12–1.32) and serum PTH 192 pg/mL (ref 11–65). Technetium-99 sestamibi scan revealed a low attenuating mass with focal and persistent uptake just inferior to the left thyroid lobe. She subsequently underwent left inferior parathyroidectomy, which confirmed parathyroid adenoma, with resultant normalization of serum calcium and PTH. Due to her young age of diagnosis genetic testing was performed which revealed a mutation if CDC 73. Discussion: CDC 73 mutation is known cause of inheritable neoplasia’s with a high prevalence of parathyroid dysfunction. Although penetrance and expression is variable, the mutation is associated primarily with Hyperparathyroidism Jaw Tumor Syndrome (HPT-JT), Familial Isolated Hyperparathyroidism and sporadic parathyroid carcinoma. Our patient had an allele mutation associated with HPT-JT. This syndrome classically presents with parathyroid adenoma, ossifying tumors of the mandible and renal or uterine neoplasms. The mutation is inherited in an autosomal dominant pattern and family history plays a key role in diagnosis of this rare condition. This patient had an early age of onset for hyperparathyroidism and a family history suggestive of an inherited calcium metabolism disorder. A single parathyroid adenoma is the most common presentation and surgical resection is often curative of hyperparathyroidism. In Hyperparathyroidism Jaw Tumor Syndrome patients classically develop ossifying tumors of the mandible and renal or uterine neoplasms in addition to parathyroid lesions. Rarely patients with CDC 73 mutation can develop parathyroid carcinoma. For this reason it is recommended that all first degree relatives undergo testing for CDC 73 mutation. This patient currently has no evidence of jaw, uterine or renal tumors on screening imaging. Ovarian tumors have been described separately to be associated with CDC 73 mutation, this patient may actually have an unrecognized phenotype of CDC 73 mutation. Given the potential impact of inheritable neoplasia, all young patients with unexplained hyperparathyroidism should be considered for genetic screening.

P708 Multimodality imaging of catheter-related right atrial thrombus: a case report

Abstract INTRODUCTION Catheter-related right atrial thrombosis (CRAT) is potentially life-threatening complication of long-term indwelling central venous catheters (CVC), which are used extensively in various patients. Reported incidence of CRAT is variable (2-62%) and probably underestimated due to predominantly asymptomatic course and lack of routine screening. Main pathogenic mechanisms that promote CRAT include mechanical and chemical injury of atrial endocardium by the catheter and infused drugs, stasis of blood and hypercoaguability. Differential diagnosis between thrombus and other intracardiac masses, especially myxoma, is sometimes very difficult and requires multimodality imaging studies. CASE PRESENTATION 62-years old patient after chemotherapy of lymphoma, in remission, with subcutaneous CVC inserted in right subclavian vein, which was used as chemotherapy port several years ago, was sent to emergency department because right atrial mass was found on elective outpatient transthoracic echocardiography (TTE). Urgent computed tomography (CT) was performed and showed well defined, 1.8 x 2.0 cm large, low attenuating mass with some calcifications. Several features were primarily suggestive of myxoma, however differentiation from thrombus was not possible. Patient was admitted to hospital, where transesophageal echocardiography (TEE) confirmed the presence of heterogenous mass attached to right atrial free wall with tumor-like movement. Mobile catheter tip was nearby and touching the mass irregularly. Although in addition to CT also some echocardiographic characteristics were more consistent with myxoma, there was still high clinical suspicion of CRAT due to multiple risk factors for thrombosis. Cardiac magnetic resonance imaging (MRI) using cine sequence was performed for further evaluation and revealed mobile, homogeneously low-signal intensity mass that remained hypointense on contrast-enhanced sequences (first pass perfusion and late gadolinium enhancement), which led to final diagnosis of thrombus. CONCLUSION CRAT should be suspected and anticipated in all, also asymptomatic patients with long-term indwelling CVC (e.g. for chemotherapy, parenteral nutrition, hemodialysis..), majority of whom have additional multiple risk factors for thrombosis. Routine screening for CRAT can provide early diagnosis and treatment and should be considered especially in high-risk patients in order to prevent potentially severe complications. Although echocardiography is the modality of choice for screening, further imaging modalities, e.g. CT and MRI are often required to differentiate thrombus from myxoma or other cardiac masses. Our case demonstrates difficult differential diagnosis of right atrial mass in an asymptomatic patient with a long-term indwelling chemotherapy port, in whom multimodality imaging studies were performed, but only MRI with contrast-enhanced sequences providing superior tissue characterization, could differentiate between CRAT and myxoma. Abstract P708 Figure. Multimodality imaging of atrial thrombus

Epidermoid Cyst in the Intrapancreatic Accessory Spleen: A Case Report and Review of the Literature

Abstract Epidermoid cyst in the intrapancreatic accessory spleen (ECIAS) is an exceedingly rare nonneoplastic entity. It generally does not require therapeutic intervention, but it is often misdiagnosed preoperatively as a cystic tumor, such as a mucinous cystic neoplasm or a cystic degeneration in a solid pancreatic neuroendocrine tumor or solid pseudopapillary neoplasm. We herein report a rare case of ECIAS in a 33-year-old African American man with a history of end-stage renal disease secondary to IgA nephropathy, congestive heart failure, and sickle cell trait who was referred to our facility for a renal transplant workup. A contrast-enhanced abdominal computed tomography during the workup revealed a bilobed low attenuating mass (3.4 × 3.4 × 2.5 cm) in the tail of the pancreas. Because malignancy could not be excluded, the patient underwent a distal pancreatectomy and splenectomy. Gross examination of the surgical specimen revealed a smooth-walled, multiloculated cyst (3.7 × 2.7 × 2.0 cm), containing serous fluid within the pancreatic parenchyma. Microscopically, the cyst was lined by nonkeratinizing stratified squamous epithelium without skin appendages, surrounded by benign splenic tissue in the pancreatic parenchyma. No dysplasia or malignancy was seen. Immunohistochemically, the lining epithelium was positive for p63, CK5/6, and CEA and negative for CA19-9, which supports the above diagnosis. The postoperative course was uneventful. In conclusion, ECIAS is a rare benign entity that can mimic malignant conditions and should be considered in the differential diagnosis of cystic lesions in the tail of pancreas.

Pancreatic Head Mass: A Rare Manifestation of Granulomatosis With Polyangiitis

A solid pancreatic mass is found to be malignant 95% of the time, while inflammation accounts for the remaining cases. We report a case of granulomatosis with polyangiitis (GPA) presenting as an inflammatory mass initially suspected to be metastatic pancreatic cancer. This is a 73-year-old male who presented to the ED with weakness, fevers, night sweats, and weight loss. His medical history was significant for severe chronic sinusitis and nasal polyps. On physical examination, he was noted to have bilateral lower extremity nodular purple plaques with necrotic centers. Laboratory studies were significant for leukocytosis, mildly elevated alkaline phosphatase, normal kidney function, transaminases and bilirubin. CT imaging demonstrated a low-attenuation mass in the pancreatic head along with multiple cavitary pulmonary nodules without hepatic lesions. Our differential diagnoses included metastatic pancreatic cancer versus an autoimmune process. CA 19-9 and CEA were within normal limits. An autoimmune work-up showed negative ANA, positive RF, elevated WSR, elevated IgE, and an elevated C-ANCA. Skin biopsy yielded leukocytoclastic vasculitis with granular fluorescence of C3 and IgG. Biopsy of lung nodules revealed extensive necrosis with acute neutrophilic infiltrates, fibrin thrombi, multinucleated giant cells, consistent with GPA. He was started on high dose steroids. He was discharged with plans for repeat imaging and biopsy of the pancreatic mass. A pancreatic mass in an elderly patient is highly concerning for cancer, which was our primary differential diagnosis. The absence of hepatic involvement and normal tumor markers decreased the likelihood of a primary pancreatic cancer with lung metastases. Due to his history of recurrent sinusitis, nasal polyps, and skin lesions, an autoimmune etiology was explored. A positive C-ANCA coupled with the lung biopsy findings established the diagnosis of GPA, a very rare cause of pancreatic masses. Most cases detailing GI manifestations of GPA present with pancreatitis or painless jaundice, but few have reported pancreatic masses. Necrotizing vasculidities can mimic pancreatic carcinoma and should be considered in the differential diagnosis of atypical cases. It is important to distinguish a pancreatic mass caused by GPA from pancreatic cancer due to the significant differences in treatment and prognosis. More studies are needed to determine whether these pancreatic masses should be biopsied or followed with imaging.1406_A.tif Figure 1: ßLungßonstrating extensive necrosis with acute neutrophilic infiltrates, fibrin thrombi, and multinucleated giant cells.1406_B.tif Figure 2: Low attenuation mass anteriorly in the pancreatic head measuring approximately 2.0 cm. The margins of the mass are inseparable from posterior wall of the duodenal bulb.1406_C.tif Figure 3: Bilateral lower extremity lesions described as nodular purple plaques with necrotic centers.

Clear Cell Hidradenoma: Characteristic Imaging Features on Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging.

The purpose of this study was to evaluate the imaging features of clear cell hidradenoma on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). The radiologic and pathologic databases at 2 medical institutions were searched retrospectively from 2004 to 2016 to identify patients with a diagnosis of clear cell hidradenoma. Ultrasonographic, CT, and MRI features were described, and pathologic specimens were reviewed. There were 5 female and 4 male patients. The mean patient age was 48.9 years (range, 28-70 years). Five patients underwent only US; 2 patients underwent only CT; 1 patient underwent both US and CT; and 1 patient underwent US and MRI. Most of the tumors were located primarily in the subcutaneous fat layer. The mean tumor size was 18.4 mm. On US, 6 masses had a heterogeneous echo texture, including an anechoic portion with protruding echogenic portions. Two masses had multiple septa in the anechoic portion. On color Doppler US, blood flow was both central and peripheral in 5 patients. All 3 cases seen on CT presented as a low-attenuation mass with an enhanced solid internal nodule. On MRI, the mass showed heterogeneous signal intensity on T2-weighted images and enhancement of the peripheral wall and internal solid component on contrast-enhanced T1-weighted images. Clear cell hidradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, appears as a cystic mass with an internal solid nodule, and occasionally has multiple septa on US, CT, and MRI.

Stuck in the Gut. An Unusual Duodenal Bezoar Following Pyloric-exclusion Gastrojejunostomy

Introduction: Bezoars are foreign-bodies classified by their composition, with phytobezoars (indigested vegetable matter) being the most common. They are a rare entity usually found incidentally on imaging or routine endoscopy and tend to occur in patients with altered gastric anatomy such as following surgery. To our knowledge, no case reports exist of a small-intestinal phytobezoar following an unreversed pyloric-exlusion gastrojejunstomy. Case: A 19 year-old female with a history of blunt abdominal trauma at 18-months requiring pyloric-exclusion gastrojejunostomy presented with right-upper-quadrant (RUQ) abdominal pain, nausea, vomiting, and diarrhea associated with a 20-lb weight loss over the past few months. Her vital signs, complete blood count, and basic metabolic profile were unremarkable. Abdominal computed tomography with intravenous contrast revealed a large, ovoid, low-attenuation mass within the RUQ measuring 6.6 cm x 5.3 cm x 6.9 cm. Magnetic resonance imaging confirmed a mass in the duodenal bulb, most consistent with a bezoar (Panel A). Subsequent upper endoscopy exposed the yellow-colored bezoar extending from the 3rd portion of the duodenum into the proximal jejunum (Panel B). Additionally, it was noted on endoscopy that the patient's pyloric-exclusion was never reversed, suggesting the bezoar likely formed due to years of reflux from the jejunum into the duodenum. A schematic diagram of the location of the bezoar is provided (Panel C). Due to technical difficulty reaching the bezoar and insufficient pyloric dilatation endoscopically, she ultimately required surgical intervention with pyloroplasty to achieve complete removal of the bezoar. At follow-up, she reported resolution of symptoms and improvement in appetite with weight gain and regular bowel function.Figure: MRI showing mass in the duodenal bulb.Figure: EGD showing the yellow-colored bezoar extending from the 3rd portion of the duodenum into the proximal jejunum.Figure: Schematic diagram indicating the procedure (pyloric-exclusion gastrojejunostomy) and anatomic location of the bezoar.Discussion: Pyloric-exclusion gastrojejunostomy is performed as a temporizing measure when duodenal ischemia is suspected, as in our patient following blunt abdominal trauma. However, in unusual cases where patients do not have the pyloric exclusion reversed, reflux of food material into the duodenum can occur and result in a symptomatic bezoar formation.

Intrathoracic lipoblastoma presenting with severe respiratory distress

Abstract Lipoblastoma is a rare benign tumour which originates from an adipose tissue. In this study we report the case of a three year old boy who presented with a large intrathoracic tumour occupying the whole of the left hemithorax. He presented in severe respiratory distress. A chest X-ray showed total opacity of the left hemithorax, and CT-scan showed a low attenuation mass inkeeping with fat in the left hemithorax. A complete resection of a tumour was undertaken, with histopathology report confirming the diagnosis of lipoblastoma. The relevant literature review was done. At three and six months follow up, there was no recurrent tumour on imaging and the child had started thriving well.

S49 - Primary hepatic lymphoma: a monoinstitutional experience

Background: Primary hepatic lymphoma (PHL) is a lymphoproliferative disease confined to the liver without evidence of spleen, lymph nodes or bone marrow involvement. It is a rare entity accounting for 0.4% of cases of extranodal NHL, and only about 0.016% of all cases of NHL. A correlation between PHL and hepatitis C virus (HCV) has been recently demonstrated, while the role of hepatitis B virus is less clear. Patients and methods: We present a series of four patients (pts) who underwent surgery (left lobectomy) for the occurrence of hepatic lesions highly suspected to be hepatocellular carcinoma (HCC). They all presented with hepatomegaly as the only sign of liver disease and 3 of them were in follow-up for HCV related hepatitis. Results: According to radiological and ultrasonography (US) criteria the presumptive diagnosis was HCC but, after resection, the final diagnosis was B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) in 2 cases and diffuse large B cell lymphoma (DLBCL) in the other 2 cases. Systemic staging was negative in all pts. Conclusions: PHL is a rare entity often difficult to differentiate from benign and neoplastic lesions involving the liver. PHL may appear at CT scan as homogeneous low attenuation masses with a central area of low intensity, indicating necrosis. A thin rim of enhancement after contrast can be observed in 20% of patients, but about 50% of PHL lesions do not enhance. Diffuse infiltrative disease can present as hepatomegaly with modest alterations in liver density. US may show the presence of hypoechoic homogeneous masses. Magnetic resonance (MR) usually demonstrates hypo- or iso-intense lesions on T1-weighted images, with no enhancement after contrast, hyper-intense on T2-weighted images. MR is much more sensitive for diffuse infiltration of the liver than CT or US; however no MR characteristics are specific for hepatic lymphoma. According to recent guidelines a needle biopsy is not indicated for cirrhotic patients when imaging is diagnostic for HCC lesions > 1-2 cm. The clinical diagnosis of PHL is challenging since no specific sign or symptoms are usually observed. Particular attention is required for patients with known chronic liver disease since multiple confounding factors such as hepatitis C are present and liver biopsy is not mandatory. The combination of US, CT, and MR may be useful, but liver biopsy remains the most valuable tool for the diagnosis, in order to avoid unnecessary surgery.

Near Obstructing Tracheal Lipoma

Figure 1: Chest radiograph showing an occupied lesion over the trachea. Figure 2: CT of the chest revealed a near obstructing tracheal tumor with low attenuation suggesting a fat containing lesion. Figure 3: Bronchoscopic image showing a huge rounded tumor with almost 90% lumen obstruction. in the trachea. Clinical Presentation A 32-year-old man was evaluated for a 6-month history of dyspnea, and non-productive cough. On physical examination, he was found to have stridor breath sounds. A chest radiograph showed a mass over the trachea (Figure 1). A contrast enhanced chest CT showed a low attenuation mass in the trachea (Figure 2). Fiberoptic bronchoscopy (FB) revealed a huge rounded tumor with almost 90% lumen obstruction (Figure 3). It was successfully excised by the FB under the extracorporeal membrane oxygenation support. The histopathological examination of the biopsies showed submucosal lipoma. Trachea lipoma is a rare benign tumor of the respiratory tract, and it’s accounting for 0.1% of lung tumors [1]. Clinical symptoms include dyspnea, cough, chest pain, hemoptysis or wheezing, which often occur late depending on the degree of airway obstruction. It is easy to be misdiagnosed as asthma or chronic obstructive pulmonary disease. The main treatment for trachea lipoma is surgical or endoscopic resection.

Appendiceal mucocele due to mucinous adenoma diagnosed by computed tomography colonography.

An asymptomatic 50-year-old man underwent a low-dose computed tomography colonography (CTC) for screening purpose. The CTC examination was negative for colonic mass or polyps, but axial and coronal two-dimensional CTC images (Fig. 1) showed a large elongated low-attenuation mass in the expected region of the appendix, in line with an appendiceal mucocele. Three-dimensional CTC endoluminal images (Fig. 2) showed the mass bulging into the cecal lumen. The patient underwent appendectomy with partial right hemicolectomy and is in good health. Pathology confirmed an appendiceal mucocele from mucinous adenoma, and in particular the histological examination revealed a low-grade mucinous appendiceal neoplasm with negative regional lymph nodes and with no signs of mucinous peritoneal carcinomatosis. This case shows the crucial role of CTC in the diagnosis of an unknown submucosal disease [1], potentially malignant if not early diagnosed [2,3]; that diagnosis would not have been made if the patient had had an optical colonoscopy or a double contrast barium enema instead of CTC, since both tests fail to evaluate extraluminal areas.