Intrapancreatic Accessory Spleen Research Articles

Differentiation of intrapancreatic accessory spleen from small hypervascular neuroendocrine tumor of the pancreas: textural analysis on contrast-enhanced computed tomography.

Intrapancreatic accessory spleens (IPASs) are usually misdiagnosed as pancreatic neuroendocrine tumors (PNETs). Texture analysis is valuable in tumor detection, diagnosis, and staging. To identify the potential of texture features in differentiating IPASs from small hypervascular PNETs. Twenty-one patients with PNETs and 13 individuals with IPASs who underwent pretreatment dynamic contrast-enhanced computed tomography (CT) were retrospectively analyzed. The routine imaging features-such as location, size, margin, cystic or solid appearance, enhancement degree and pattern, and lymph node enlargement-were recorded. Texture features, such as entropy, skewness, kurtosis, and uniformity, on contrast-enhanced images were analyzed. Receiver operating characteristic (ROC) analysis was performed to differentiate IPASs from PNETs. No significant differences were observed in margin, enhancement degree (arterial and portal phase), lymph node enlargement, or size between PNETs and IPASs (all P > 0.05). However, IPASs usually showed heterogeneous enhancement at the arterial phase and the same degree of enhancement as the spleen at the portal phase, both of which were greater than those of PNETs (69% vs. 35%, P = 0.06; 100% vs. 29%, P = 0.04). Entropy and uniformity were significantly different between IPASs and PNETs at moderate (1.5) and high sigma values (2.5) (both P < 0.01). ROC analysis showed that uniformity at moderate and high sigma had the highest area under the curve (0.82 and 0.89) with better sensitivity (85.0-95.0%) and acceptable specificity (75.0-83.3%) for differentiating IPASs from PNETs. Texture parameters have potential in differentiating IPASs from PNETs.

Diagnóstico por imagen de anomalías en el número y localización del bazo

In imaging studies, some developmental anomalies such as perisplenic accessory spleen are easily recognizable due to their high incidence. However, other, less common anomalies such as intrapancreatic accessory spleen, splenopancreatic fusion, splenogonadal fusion, heterotaxy, and wandering spleen, as well as acquired conditions such as splenosis, can pose diagnostic difficulties. This aim of this review is to show the imaging diagnosis and differential diagnoses of these uncommon splenic anomalies.

Pitfalls in pancreatic lesion diagnostics: an accessory intrapancreatic spleen

Introduction. Accessory spleen (splenunculus) is one of the most common benign congenital anomalies in humans. The location of splenunculus may vary from perisplenic, greater omental or mesenterial to intraparenchymal (pancreas, stomach, duodenum, etc.). In the latter case, the additional spleen is called ectopic (from the greekektoposdisplaced). Most frequently detection of such splenic lobules occurs accidentally via abdominal ultrasound.Objective: two cases of verified intrapancreatic accessory spleen (IPAS) and main criteria for differential diagnosis with other hypervascular pancreatic lesions.Materials and methods. We present two case reports: a 43-year-old woman with a history of kidney cancer and a healthy 61-year-old man. In both cases, pancreatic neuroendocrine neoplasia (NEN) was initially suspected. Preoperative diagnostics included abdominal ultrasound examination and multiphase dynamic computed tomography (CT) with intravenous bolus nonionic iodine-based contrast agent (native, arterial – 10 sec, venous – 60 sec and delayed – 300 sec after threshold density of 150 HU in the aorta was exceeded). In one case magnetic resonance imaging (MRI) including axial, sagittal and coronal T1and T2-weighted images, diffusion-weighted images and dynamiccontrast-enhanced series with gadolinium chelate was performed. Both patients underwent robotic assisted distal pancreas resection. Morphological examination revealed IPAS.Results. In contrast-enhanced computed tomography IPAS has densitometric parameters similar to the spleen. Generally, magnetic resonance imaging does not differentiate IPAS, NEN and hypervascular metastases, since all three are generally T2-hyperintense and T1-hypointense. Contrast enhancement pattern with gadolinium chelateswas similar to CT-contrast enhancement pattern.Conclusion. Intrapancreatic accessory spleen does not require surgical treatment. Therefore, differential diagnosis between IPAS and neuroendocrine neoplasia, solid pseudopapillary tumor and hypervascular pancreatic metastases is crucial. MRI has an advantage with non-invasive diffusionweighted images (DWI). The apparent diffusion coefficient (ADC) of IPAS will be quantitatively similar to the main spleen while other lesion will demonstrate lower ADC values. Scintigraphy with red blood cells bound with 99mTc utilizes the reticuloendothelial system (RES) in the spleen demonstrating characteristic uptake in the IPASand the main spleen. Ultrasound with color Doppler and contrast enhancement may be a good addition to our armamentarium. One can evaluate the vascular pedicle of the IPAS, as well as contrast agent retention in RES via sonography. We believe the multimodal approach including MRI with DWI/ADC to be the most effective.

Accessory spleen mimicking a pancreatic neuroendocrine tumor.

A 60-year-old man underwent computed tomography as part of colorectal cancer follow-up. A hypervascular nodule was found within the pancreatic tail and subsequently proved to be positive on [111In] DTPA-octreotide scan. A neuroendocrine tumor of the pancreas was supposed and a distal pancreatectomy performed. Heterotopic splenic tissue was finally proved by pathological examination. The present case suggests that intrapancreatic accessory spleen be considered in the differential diagnosis of pancreatic lesions positive on [111In] DTPA-octreotide scan.

Intrapancreatic accessory spleen mimicking a tumor of the pancreatic tail

Intrapancreatic accessory spleen mimicking a tumor of the pancreatic tail

Accuracy of apparent diffusion coefficient in differentiating pancreatic neuroendocrine tumour from intrapancreatic accessory spleen.

To evaluate and compare the accuracy of absolute apparent diffusion coefficient (ADC) and normalised ADC (lesion-to-spleen ADC ratio) in differentiating pancreatic neuroendocrine tumour (NET) from intrapancreatic accessory spleen (IPAS). Study included 62 patients with the diagnosis of pancreatic NET (n=51) or IPAS (n=11). Two independent reviewers measured ADC on all lesions and spleen. Receiver operating characteristics (ROC) analysis to differentiate NET from IPAS was performed and compared for absolute and normalised ADC. Inter-reader reliability for the two methods was assessed. Pancreatic NET had significantly higher absolute ADC (1.431x10-3 vs 0.967x10-3 mm2/s; P<0.0001) and normalised ADC (1.59 vs 1.09; P<0.0001) compared to IPAS. An ADC value of ≥1.206x10-3 mm2/s was 70.6% sensitive and 90.9% specific for the diagnosis of NET vs. IPAS. Lesion to spleen ADC ratio of ≥1.25 was 80.4% sensitive, and 81.8% specific while ratio of ≥1.29 was 74.5% sensitive and 100% specific in the differentiation. The area under the curve (AUCs) for two methods were similar (88.2% vs. 88.8%; P=0.899). Both methods demonstrated excellent inter-reader reliability with ICCs for absolute ADC and ADC ratio being 0.957 and 0.927, respectively. Both absolute and normalised ADC allow clinically relevant differentiation of pancreatic NET and IPAS. • Imaging overlaps between IPASs and pancreatic-NETs lead to unnecessary procedures including pancreatectomy. • Uniquely low ADC of spleen allows differentiating IPASs from pancreatic NETs. • Both absolute-ADC and normalised-ADC (lesion-to-spleen ADC-ratio) demonstrate high accuracy in differentiating IPASs from NETs. • Both methods demonstrate excellent inter-reader reliability.

Common and Uncommon Benign Pancreatic Lesions Mimicking Malignancy: Imaging Update and Review

There is a broad range of inflammatory, pseudotumoral, and benign lesions that may masquerade as pancreatic malignancies, often representing a challenge to the radiologist. Unawareness of these entities can lead to inadequate differential diagnoses or misdiagnosis, with important prognostic and therapeutic consequences. The purpose of this article is to revisit a spectrum of lesions, varying from common to exceedingly rare nonmalignant, that may mimic malignant pancreatic neoplasms on imaging, identifying relevant features that may contribute to reaching the correct diagnosis. Representative cases include focal fatty replacement, intrapancreatic accessory spleen, pancreatic lobulation, lipoma, autoimmune pancreatitis, focal pancreatitis, eosinophilic pancreatitis, groove pancreatitis, hemangioma, intrapancreatic aneurysm, tuberculosis, and Castleman's disease.

Diagnostic difficulties in neuroendocrine tumors - intrapancreatic accessory spleen.

Diagnostic difficulties in neuroendocrine tumors - intrapancreatic accessory spleen.

Epidermoid cysts are a characteristic feature of intrapancreatic but not of extrapancreatic accessory spleens.

Accessory spleens (ASs), ectopic splenic tissue at intrapancreatic and extrapancreatic sites, rarely contain epidermoid cysts. Our aim was to analyze the incidence of epidermoid cysts in ASs and perform an immunohistochemical analysis of its epithelial lining. We included in the study 148 ASs from 135 patients, for which pathological data were available. Eleven were intrapancreatic ASs (IPASs) and 137 were extrapancreatic ASs (EPASs). Six of the eleven (55%) IPASs contained epidermoid cysts, but they were not detected in EPASs. Immunohistochemical analysis showed that both the superficial/luminal and basal layer of the epithelial lining of epidermoid cysts in IPASs are negative for MUC2, MUC5AC, MUC6, WT-1, calretinin, thrombomodulin, uroplakin-II, and uroplakin-III. The superficial/luminal layer was positive for MUC4, CK7, and CA19-9 in all cases (100%), for CEA and HBME-1 in three cases (50%), and for MUC1, CK5/6, and CK20 in two cases (33%). The superficial/luminal layer was negative for p63 and D2-40 in all cases. The basal layer was positive for MUC1, CK5/6, p63, and HBME-1 in all six cases (100%), for CK7 and D2-40 in two cases (33%), and for CEA in one case (17%). The basal layer was negative for MUC4, CK20, and CA19-9 in all cases. Epidermoid cysts are a characteristic feature of IPASs but not of EPASs. Immunohistochemical analysis showed that the epithelial lining of epidermoid cysts in IPASs has a mixed character of glandular, squamous, mesothelial, and urothelial epithelium.

Epidermoid Cyst in an Intrapancreatic Accessory Spleen Diagnosed by Typical Radiographic Images and Endoscopic Ultrasound Fine-Needle Aspiration Findings With Contrast Agent

Epidermoid Cyst in an Intrapancreatic Accessory Spleen Diagnosed by Typical Radiographic Images and Endoscopic Ultrasound Fine-Needle Aspiration Findings With Contrast Agent

Epidermoid Cyst in an Intra-Pancreatic Accessory Spleen

The estimated prevalence of accessory spleen, most commonly found at the splenic hilum, is about 10% in the autopsy studies. The second commonly involved site is pancreas, and 1-2% of general population has intra-pancreatic accessory spleen (IPAS). Differential diagnosis of IPAS includes other solid pancreatic tumors, especially non-functioning pancreatic neuroendocrine tumors. Computed tomography scans and diffusion-weighted magnetic resonance imaging may accurately distinguish IPAS from other solid pancreatic lesions, with imaging features similar to the native spleen. Epidermoid cysts (EC) are common in the native spleen, but rarely found in IPAS. Differential diagnosis of the EC in IPAS includes other cystic lesions of the pancreas. Although the condition is extremely rare, an accurate pre-operative diagnosis can save a patient from major surgery given the benign nature of this condition. We present a case of an EC in an IPAS who underwent distal pancreatectomy with splenectomy for suspicion of malignancy.

The Accessory Spleen Is an Important Pitfall of 68Ga-DOTANOC PET/CT in the Workup for Pancreatic Neuroendocrine Neoplasm.

The aim of the study was to assess the value and potential pitfalls of Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) in patients with suspected pancreatic neuroendocrine neoplasms (pNEN). Consecutive patients referred for Ga-DOTANOC PET/CT for suspected pNEN between May 1, 2011, and October 31, 2014, were retrospectively assessed. Scan data were compared with cytological/histological final diagnosis. Pancreatic neuroendocrine neoplasm detection rate was determined on per-patient and per-lesion basis. Maximum standardized uptake values of lesions were determined. Fifty-eight patients with 65 lesions were enrolled. Twelve patients had nonconfirmed diagnosis; of these, 7 were positive and 5 negative at PET/CT. Of 46 patients with confirmed diagnosis, 36 had pNEN; of these, 33 were positive, 1 negative, and 2 nonevaluable at PET/CT. Ten patients had non-NE lesions, of which 8 were positive, 1 negative, and 1 nonevaluable at PET/CT. Of 48 patients with positive PET/CT, 8 proved to have non-NE lesions, of which 6 were intrapancreatic accessory spleen. No significant maximum standardized uptake values difference was found between pNEN and non-NE lesions. Intrapancreatic accessory spleen is an important pitfall in Ga-DOTANOC PET/CT for suspected pNEN. Cytological/histological confirmation is mandatory before any surgical procedure is undertaken.

Intrapancreatic accessory spleen (IPAS): A single-institution experience and review of the literature

IntroductionAccessory spleens located within the pancreatic parenchyma (intrapancreatic accessory spleen, IPAS) pose a unique clinical challenge. In many cases, despite imaging and other diagnostic studies, malignancy cannot be excluded and patients are subjected to pancreatic resection. We review our experience with the presentation, diagnosis, and treatment of patients with IPAS to provide insight into improving pre-operative evaluation of these patients MethodsA retrospective chart review identified seven patients who underwent surgical resection of an intrapancreatic spleen at University of Louisville Hospital between 2004 and 2015. Charts were analyzed for presenting symptoms, pre-operative imaging, operative therapy, and final pathologic evaluation. Patients were included in the study if they underwent pancreatic resection for a pancreatic mass and were diagnosed with an IPAS on final pathologic evaluation. ResultsPatient age ranged from 38 to 72 with a median age of 62.5, including five males and two females. Lesions ranged from 1.4 to 7.4 cm in maximal diameter (mean 3.8 cm). All lesions were identified as round, hypervascular, well-circumscribed masses in the pancreatic tail. The most common pre-operative diagnosis was a non-functioning pancreatic neuroendocrine tumor (NF-PNET). The most common operative approach was laparoscopic distal pancreatectomy and splenectomy. ConclusionIPAS are benign tumors commonly mistaken for pancreatic neoplasms such as NF-PNET. A combination of CT, MRI and nuclear medicine examinations can confirm the diagnosis of IPAS and prevent unnecessary surgical resection.

Epidermoid cyst of an intrapancreatic accessory spleen: a case report

Epidermoid cyst of an intrapancreatic accessory spleen: a case report

Endoscopic Ultrasound-Guided Fine Needle Aspiration Diagnosis of Intrapancreatic Accessory Spleen

Introduction: Accessory spleen (AS) is a rare congenital anomaly in which there is failure of fusion between a portion of the developing splenic tissue and the main body of the spleen. The majority of cases occur at the splenic hilum, while the second most common site is the tail of the pancreas. Intrapancreatic accessory neoplasm (IPAS) cytopathology findings include heterogeneous small lymphocytes along with traversing small vessels. Immunohistochemical staining for CD8 is a useful tool that specifically highlights the endothelial cells of the splenic sinus. Here report an additional case of IPAS diagnosed by endoscopic ultrasound (EUS) guided fine needle aspiration (FNA). Case presentation: A 20 year old Caucasian female presented as a referral to the gastroenterology department for an EUS evaluation after she had an elevated liver function test postpartum. An magnetic resonance cholangiopancreatography (MRCP) revealed an obstruction in the common bile duct and a small solid mass at the tail of the pancreas measuring 11 mm in size. She underwent an Endoscopic Retrograde Cholangiopancreatography (ERCP) with common bile duct stone removal. Endoscopic ultrasound (EUS) with FNA was performed and revealed a single hypoechoic oval welldemarcated 11.4 mm x 8.9 mm pancreatic solid mass at the tail of the pancreas. Cytopathology revealed a benign intrapancreatic accessory spleen. Cell block sections displayed branching thin walled blood vessels surrounded by lymphoid cells that shows positive immunoreactivity for CD8. Immunohistochemical stains were positive leukocyte lymphoid antigen. Conclusion: IPAS is a benign congenital anomaly that may mimic a pancreatic neoplasm. FNA can be performed for diagnosis. The use of a combination of common cytomorphologic features, immunohistochemical stains and radiologic findings will enable an accurate diagnosis and prevent unnecessary surgical procedures.

Magnetic Resonance Imaging Findings of Intrapancreatic Accessory Spleen.

Magnetic Resonance Imaging Findings of Intrapancreatic Accessory Spleen.

Diagnosis of an intrapancreatic accessory spleen by sonazoid-enhanced ultrasonography

Diagnosis of an intrapancreatic accessory spleen by sonazoid-enhanced ultrasonography

Pancreatic Incidentaloma: Differentiating Nonfunctioning Pancreatic Neuroendocrine Tumors from Intrapancreatic Accessory Spleen

To improve the preoperative assessment of pancreatic incidentalomas (PIs) by analysis of 1 index case and characterization of the published features of intrapancreatic accessory spleen (IPAS) compared to pancreatic neuroendocrine tumor (PNET). A search of the literature using the online database MEDLINE. In all, 46 cases of IPAS have been described to date: 17 were "presumed" as IPAS based on technetium-99m (Tc-99m) scanning, fine-needle aspiration (FNA) stain for CD8, or contrast-enhanced sonography; 29 were misdiagnosed as PNET and underwent surgery. The pancreatic lesions were 1) mostly solitary; 2) solid on imaging; 3) well defined; 4) located predominantly at the pancreatic tail; 5) not exceeding 3 cm in the largest diameter; 5) all detected in adults (22-81 years); 6) not related to sex. In subjects referred for surgery, standard imaging studies/imaging protocols did not differentiate between IPAS and PNET. FNA was performed in 5/46 cases, all of which were false-positive for PNET. Immunohistochemical staining for T-cells on FNA material and specific imaging features (characteristic arciform splenic enhancement pattern on dynamic computed tomography [CT]; nuclear scintigraphies with radioisotope specifically trapped by splenic tissue [Tc-99m]) or contrast-enhanced sonography offered valuable clues. Still, distal pancreatectomy and splenectomy was carried out in 72%, and the rest had distal pancreatectomies. IPAS should be considered before surgery in patients with PIs. A new practical algorithm is presented for better preoperative evaluation of such lesions; it combines the recognition of early indicators and sequential consideration of cytologic and imaging features to decrease the hazards of unnecessary major surgery. CT = computed tomography EUS = endoscopic ultrasound FNA = fine-needle aspiration HDRBC = heat-damaged red blood cells IPAS = intrapancreatic accessory spleen MRI = magnetic resonance tomography NF-PNET = nonfunctioning pancreatic neuroendocrine tumor PET = positron emission tomography PNET = pancreatic neuroendocrine tumor PI = pancreatic incidentalomas SPIO = superparamagnetic iron oxide Tc-99m = technetium-99m.

Pancreatic Incidentalomas: Is it Net or Not?

FNA = fine-needle aspirate IPAS = intrapancreatic accessory spleen PNET = pancreatic neuroendocrine tumor.

Diagnostic difficulties and therapeutic choices in intrapancreatic accessory spleen: case reports

Diagnostic difficulties and therapeutic choices in intrapancreatic accessory spleen: case reports