Extraosseous Soft Tissue Research Articles

Ewing’s Sarcoma of the Adrenal Gland; A Rare Extraosseous Presentation

Ewing sarcoma also known as peripheral primitive neuroectodermal tumors (ES/PPNETs) usually produce in the chest wall, extraosseous soft tissues, and long or flat bones, however only rarely in solid organs. Although they can develop in any part of the body, development in the adrenal glands is very uncommon. We present a case of Ewing sarcoma (PNET) of the adrenal gland and the extraordinary diagnostic and therapeutic challenges faced during its diagnosis. Early detection of extraosseous disease with radiological imaging and the multimodality treatment strategy lowers morbidity and death in Ewing’s sarcoma of the adrenal gland.

Locally Aggressive Rib Hemangioma With Glomeruloid and Papillary Features - Expanding the Clinicopathologic spectrum of Bone Hemangiomas.

Intra-osseous hemangiomas are uncommon tumors that can present diagnostic and treatment dilemmas. Bone hemangiomas with papillary and glomeruloid growth patterns are exceptionally rare. We present an example of an intra-osseous hemangioma of the rib displaying aggressive features on both radiology and histology. Morphologically, prominent papillary and glomeruloid architectural patterns were observed, in addition to features of cavernous and capillary hemangiomas. Extensive extra-osseous soft tissue involvement was seen. Awareness of the diverse histological features and locally aggressive behavior of bone hemangiomas is important in avoiding over-interpretation as a malignant lesion.

Intraosseous conventional central chondrosarcoma does not metastasise irrespective of grade in pelvis, scapula and in long bone locations

BackgroundHistological grade has been regarded as the most important prognostic factor in conventional central chondrosarcoma. To evaluate whether the presence of an extraosseous tumour component is associated with a decreased metastasis-free survival or disease-specific survival and alternatively to develop a simple prognostic and clinical decision-making tool. Material and methodsWe searched two prospectively maintained international sarcoma centre databases for primary non metastatic central conventional chondrosarcomas of all grades in pelvis, scapula or long bone location, undergoing curative treatment, diagnosed between 2000 and 2020. Pre-treatment MRI scans were reviewed for the presence of an extraosseous mass. The metastasis-free survival (MFS) and disease-specific survival (DSS) were estimated by the Kaplan-Meier method from surgery to event, death or last follow-up. Results336 patients were identified between 2000 and 2020, undergoing surgical treatment for conventional central chondrosarcoma. 111 patients (33 %) had grade 1 tumours, 149 patients (44 %) had grade 2, and 76 patient (23 %) had grade 3 chondrosarcomas determined as the highest grade in the final resected specimen. An extraosseous soft tissue component was more frequent in higher grade tumours (p < 0.001) and present in 200 cases (60 %). None of the patients with an intraosseous tumour developed metastases or died of the disease. For patients with extraosseous tumour component, MFS was 92 % (95 % CI, 96–100) at 2-years and 74 % (95 % CI, 67–81) at 10-years and DSS was 91 % (95 % CI, 87–95) at 2-years and 75 % (95 % CI, 68–82) at 10-years. The MFS and DSS was significantly different (p < 0.001) for those patients with or without an extraosseous tumour component, irrespective of grade or anatomical location. DiscussionThe results of this study has shown that the metastatic potential of intraosseous conventional central chondrosarcoma is negligible. The presence of an extraosseous soft tissue component may be used for prognostication and to guide treatment pathways for patients with central cartilage tumours.

SAT535 ANKRD26-RET Fusion Positive Metastatic Papillary Thyroid Carcinoma - Advanced Presentation of a Rare Mutation

Abstract Disclosure: H. Hashmi: None. A. Ankireddypalli: None. L. Burmeister: None. A. Nelson: None. K. Amin: None. Background: While rearranged during transfection (RET) protooncogene mutations have been commonly associated with thyroid malignancy, ankyrin repeat domain containing protein 26 (ANKRD26) has been primarily linked to hematologic malignancy. Exon 29 of ANKRD26 (Chromosome [Chr] 10p12.1) has been shown to fuse with exon 12 of RET (Chr 10q11.21), resulting in a genetic fusion mutation ANKRD26:RET. This is a rare genetic mutation in papillary thyroid cancer with only one previously reported case. We report the first case in the US of this novel genetic mutation with a unique clinical presentation. Clinical Presentation: A 48-year-old, male patient presented with lower back pain radiating to the lower extremities of one year duration. MRI lumbar spine revealed an irregular mass lesion in the L1 vertebral body with extraosseous soft tissue extension, L1 compression fracture and extension into the T12 body. CT CAP revealed a 4.8 x 3.6 cm, heterogenous right thyroid lobe with tracheal compression and sub centimeter pulmonary nodules in the left lower and right middle lobes. Biopsy of the L1 paravertebral mass was diagnostic for metastatic thyroid carcinoma of a follicular pattern. Molecular testing with a next generation sequencing fusion profile assay was positive for ANKRD26:RET gene rearrangement. Thyroid ultrasound was notable for a solid, hypoechoic, 3.2 x 3.1 x 2.9 cm right lobe nodule with echogenic foci and level 4 lymph nodes with loss of reniform shape and fatty hilum. FNA of the nodule and right level 4 lymph node was suspicious for follicular neoplasm. The patient was admitted for acute cord compression necessitating extensive laminectomy, vertebral reconstruction and resection of the L1 paraspinal tumor. Pathology was positive for metastatic, follicular variant, papillary thyroid carcinoma. Total thyroidectomy, central and right modified radical neck dissection was performed. Pathology demonstrated a 4.2 cm papillary carcinoma, follicular type with tall cell variant; confined to the thyroid. Extensive angioinvasion (≥ 4 vessels) and lymphatic invasion was present. 10/32 positive lymph nodes. TNM grading was T3aN1bM1. Summary: The only other case of ANKRD26-RET fusion positive papillary thyroid cancer in the literature was reported by Staubitz et al in Germany in 2019. They reported a case of a 78-year-old male with follicular variant papillary thyroid carcinoma (pT3,pN0,M0). To our knowledge, our case is the second worldwide and the first to be reported in the United States of this rare fusion protein positive thyroid cancer. Such an aggressive presentation with distant osseous metastases has to our knowledge not been previously described. Conclusion: The clinical and therapeutic implications of this rare genetic mutation are not currently well elucidated. We present this case with the intent to expand the existing literature and increase recognition of this rare genetic mutation. Presentation Date: Saturday, June 17, 2023

Bone Tumor Risk Stratification and Management System: A Consensus Guideline from the ACR Bone Reporting and Data System Committee

The assessment and subsequent management of a potentially neoplastic bone lesion seen at diagnostic radiography is often complicated by diagnostic uncertainty and inconsistent management recommendations. Appropriate clinical management should be directed by risk of malignancy. Herein, the ACR-sponsored Bone Reporting and Data System (Bone-RADS) Committee, consisting of academic leaders in the fields of musculoskeletal oncology imaging and orthopedic oncology, presents the novel Bone-RADS scoring system to aid in risk assignment and provide risk-aligned management suggestions. When viewed in the proper clinical context, a newly identified bone lesion can be risk stratified as having very low, low, intermediate, or high risk of malignancy. Radiographic features predictive of risk are reviewed include margination, pattern of periosteal reaction, depth of endosteal erosion, pathological fracture, and extra-osseous soft tissue mass. Other radiographic features predictive of histopathology are also briefly discussed. To apply the Bone-RADS scoring system to a potentially neoplastic bone lesion, radiographic features predictive of risk are each given a point value. Point values are summed to yield a point total, which can be translated to a Bone-RADS score (1-4) with corresponding risk assignment (very low, low, intermediate, high). For each score, evidence-based and best practice consensus management suggestions are outlined. Examples of each Bone-RADS scores are presented, and a standardized diagnostic radiography report template is provided.

Subperiosteal Schwannoma of the Humerus: A Case Report and Review of Literature

There are numerous conditions that arise from the surface of bones including both neoplastic and non-neoplastic entities. Schwannoma had been reported to be one of those conditions originating from the bone surface with variable proposed theories on it’s origin. We present a unique case of subperiosteal schwannoma arising from the humerus in a 40 years old female with history of painful swelling for two years. Radiograph showed cortically based lytic lesion located in the lateral distal humeral metaphysis with periosteal reaction and cortical scalloping. MRI showed the same juxtacortical lesion with a large extraosseous soft tissue component. It demonstrates intermediate T1 signal intensity and high signal intensity on T2 weighted images with intense enhancement. US guided biopsy showed benign peripheral nerve sheath tumour, consistent with schwannoma. The patient underwent complete rescetion with no complications or documented recurrence till the latest follow-up. In conclusion, subperiosteal schwannoma should be kept in the differential diagnosis in patients presenting with bone surface lesions associated with unexplained vague pain and swelling for a prolonged period of time.

Finger Pain as an Uncommon Primary Manifestation of Lung Carcinoma

A 54-year-old patient presented with progressive pain for one month in the second finger of the right hand with an emphasis on the proximal interphalangeal (PIP) joint. Subsequent magnetic resonance imaging (MRI) showed a diffuse intraosseous lesion at the base of the middle phalanx with destruction of the cortical bone and extraosseous soft tissue. An expansively growing chondromatous bone tumor, e.g., a chondrosarcoma, was suspected. After incisional biopsy, the pathologic findings finally revealed, surprisingly, a metastasis of a poorly differentiated non-small cell adenocarcinoma of the lung. This case illustrates a rare but important differential diagnosis for painful finger lesions.

Hepar-1 Positive Prostatic Adenocarcinoma: A Case Report and Review of Literature

Abstract Introduction/Objective Poorly differentiated metastatic malignancy in patients with a history of more than one known primary tumor, such as a history of both hepatocellular and prostatic carcinoma as seen in our case, can be challenging. Both tumors are CK7/CK20 positive, and both can be reactive for hepar-1, as has been demonstrated in the current case, and rarely described in the literature. Methods/Case Report Herein we present a sixty-three-year-old male who presented for follow-up of his lower back pain in the setting of hepatocellular carcinoma. MRI of the spine was suggestive of an expansile metastatic lesion in the C2 vertebral body with extraosseous soft tissue extension resulting in moderate to severe central canal and left foraminal narrowing at C2-3. Multiple additional metastatic lesions were visualized throughout the cervical upper thoracic spine as detailed above. Vertebral body biopsy showed metastatic adenocarcinoma with sheets of neoplastic cells infiltrating the medullary spaces. The patient’s history of hepatocellular carcinoma was noted, and immunohistochemical staining for HepPar1 with appropriate control was performed and found to be diffusely reactive in the tumor cells. However, tumor cells were also positive for PSA, PSAP, and NKX3.1 (Fig-1-A-D, H&amp;E, Hepar-1, PSAP, PAP). This immunoprofile is consistent with a prostatic origin of the tumor cells, and a diagnosis of metastatic prostatic adenocarcinoma was given. Results (if a Case Study enter NA) NA. Conclusion Hepar-1 and even arginase-1 have been observed in rare subsets of prostatic acinar adenocarcinoma. Even in the setting of PSA and PSAP negative metastatic disease in patients with a history of hepatocellular carcinoma, we suggest utilizing additional stains suggestive of a prostatic origin, such as NKX3.1, and even molecular studies. This could be useful diagnostic approach to help differentiate between the two neoplasms in such patients.

Odontoma, an Accidental Finding during Curettage: A Case Report

Odontomas are common occurrences in the oral cavity and can be classified as complex or compound. Compound odontomas are rare and present in the extra-osseous soft tissues. In this case, the odontoma led to the impaction of permanent teeth, due to which removal of the lesion was advised.

A Rare Presentation of Endometrial Cancer recurrence with Scapular metastasis: A Case Report and Review of the Literature

Bone metastasis from endometrial cancer is rare. Most of the early stage endometrial cancers with endometrioid histology are confined to the uterus at the time of diagnosis and confer a good prognosis. Endometrial metastases to the bone are generally restricted to the axial skeleton, including the pelvis and thoracolumbar vertebrae. Skeletal metastases in the appendicular skeleton such as scapula, clavicle and extremities to tibia, and tarsus are rarely reported. We present the case of a 50-year-old woman with diagnosis of endometrioid adenocarcinoma of the endometrium, FIGO stage IB, grade 2, with lympho-vascular space invasion who developed recurrence within 10 months with bone metastasis to left scapula and extraosseous soft tissue mass over left shoulder. There are very few cases reported in literature of scapular metastases in an early-stage endometrial carcinoma. We discuss evaluation, treatment options, overall survival rates and provide a literature review of prior published reports.

Magnetic resonance imaging in differentiating between aggressive and non-aggressive bone tumors.

While radiography remains essential in the initial evaluation of bone lesions, tissue biopsy or further imaging is often required to clarify indeterminate radiographic features. Magnetic resonance imaging (MRI) assists radiologists in evaluating lesions with indeterminate features as it has advantages in delineating tumorous tissues and bone marrow. To evaluate the association factors of MRI for bony aggressiveness. A retrospective analysis of 226 MRI examinations from patients diagnosed with bone tumors in a tertiary hospital during 2008-2018 was performed. All the MR images were interpreted by musculoskeletal radiologists without diagnostic information. The bony lesions were categorized into aggressive and non-aggressive groups using tumor margin, cortical changes, periosteal reaction, joint extension, extraosseous soft tissue involvement, tumor homogeneity, and enhancement pattern from the MR images. Univariable and multivariable analysis were applied for each feature on the MRI scans. In addition, sensitivity and specificity were calculated for MRI diagnoses of aggressive bone lesions. In total, 180 aggressive and 46 non-aggressive bone lesions were examined on MRI. The sensitivity and specificity of MRI for differentiating between aggressive and non-aggressive bone lesions were 98.89% and 50%, respectively. Ill-defined margin, cortical break, cortical signal changes, sunburst and Codman's triangle periosteal reaction, joint extension, and tumoral and heterogeneous enhancement could be predictive signs for aggressive bone lesions. MRI can be a valuable tool to assist in distinguishing aggressive from non-aggressive bone lesions. In cases of indeterminate radiographic features, MRI could be used as an additional imaging to improve diagnostic accuracy and could reduce unnecessary invasive procedures.

P-015: Is it time to revisit role of PET-CT imaging and its integration with other parameters in International Myeloma Working Group (IMWG) response assessment criteria?

<h3>Background</h3> The landscape of imaging in multiple myeloma has changed drastically since the publication of IMWG 2016 criteria. 18 F-FDG PET-CT (PET-CT) is being used more frequently, for staging, prognosis and clinical decision making. PET-CT is useful for both morphological and the metabolic activity of the plasma cells to predict and monitor clinical response. Studies have shown that subjects who achieved complete response by hematologic criteria but have PET positive lesions have poorer outcome. PET-CT has high sensitivity and specificity for detecting all lesions types. PET negativity has been equated to Minimal residual disease (MRD) negativity, and hence role of both positive and negative PET in IMWG response assessment need to be better defined. Until now extramedullary disease (EMD) and plasmacytoma evaluation have been the focus of response assessment in IMWG, although plasmacytoma is a histological, not an imaging diagnosis. Paramedullary lesions (lytic bone lesions with extraosseous soft tissue component), intramedullary lesions (soft tissue lesions in the medullary cavity) as well as pure lytic bone lesions have not been fully included in the evaluation. There is a need to better define various lesions and disease presentations seen on imaging in myeloma and their role in overall response. Additionally, role of different imaging modalities in clinical trials as well as a standardized imaging schedule, based on the presence of baseline disease burden, should be defined. The purpose of this study is to define and incorporate the imaging manifestations of myeloma of PET-CT into the IMWG criteria. A standardized PET-CT assessment approach is lacking in IMWG 2016, although Italian Myeloma Criteria for PET Use (IMPeTUs), has described PET-CT evaluation in detail, including the cut off for positivity and negativity, aligning it to 5-point Deauville Scoring (5PS). This study will also highlight the importance of PET-CT as a modality of choice in myeloma and provide a standardized methodology to integrate PET in overall assessment. We propose that myeloma lesions should be assessed in two broad categories, target (measurable) and non-target (non-measurable) lesions. Targets should include up to a total of six extramedullary and/or paramedullary lesions. Non-target lesions should include any additional measurable lesions, other soft tissue and bone lesions characteristic of myeloma, which do not meet criteria for target lesions. The status of these lesions along with any new lesions will drive an overall anatomical response. For PET-CT assessments, 5PS should be followed with liver as comparator for positivity. Metabolic responses like Complete metabolic response(CMR) etc. should be derived. An integrated imaging response can then be combined with clinical parameters to provide an overall IMWG response. This proposed guidance will help standardize integration of PET imaging in IMWG response assessment more efficiently and consistently across trials.

Management of Myelopathy due to Anterior Soft-Tissue Compression in Vertebral Hemangioma

Vertebral hemangiomas are benign but highly vascular lesions and are one of the most common lesions of the vertebral column. Anterior soft-tissue compression of spinal cord due to vertebral body hemangioma is challenging to manage. Our objective was to assess long-term clinical and radiologic effects of direct transpedicular absolute alcohol embolization, laminectomy, and short-segment instrumented fusion on resolution of extraosseous epidural soft tissue and improvement in myelopathy in cases of vertebral hemangioma causing anterior soft-tissue compression. This was a retrospective analysis that included patients with single-level vertebral hemangioma with anterior intraspinal soft-tissue growth causing spinal cord compression and clinical features of myelopathy between June 2007 and June 2019 at authors' institute. Transpedicular vertebral body injection of absolute alcohol, laminectomy, and pedicle screw rod instrumentation was performed in all patients. Clinicoradiologic outcomes of surgery were noted. We proposed a grading system for the extent of anterior extraosseous epidural soft-tissue compression. In total, 14 patients were included in study. Their mean age was 28.4 ± 14.4 years. Mean follow-up duration was 67.5 ± 36.2 months. All patients had preoperative radiologic grade 4 compression. Postoperative radiologic grading improved to grade 1 in 4 (28.6%), grade 2 in 8 (57.1%), and grade 3 in 2 (14.3%). All the patients improved neurologically after surgery. Eleven patients improved to American Spinal Injury Association (ASIA) grade E, 2 improved to ASIA D, and 1 improved to ASIA C at the last follow-up visit. Vertebral hemangiomas with anterior extraosseous epidural extension causing spinal canal compromise and myelopathy can be managed with direct transpedicular ethanol embolization, laminectomy, and short-segment instrumented fusion with resolution of the extraosseous soft tissue and improvement in myelopathy. The procedure is relatively simple, cost effective, and has a good outcome.

COMPUTER TOMOGRAPHY AND X-RAY DIAGNOSTICS OF PERIPHERAL PRIMITIVE NEUROEECTODERMAL TUMORS (PNET) IN CHILDREN

Relevance: Peripheral primitive neuroectodermal tumor (PNET) belongs to the group of malignant tumors that develop from migrating embryonic neural crest cells. PNET includes a number of nosological forms: Askin's tumor, esthesioneuroblastoma, the very peripheral primitive neuroectodermal tumor, Ewing's sarcoma . PNET accounts for 3–9% of all soft tissue tumors in children and 19% of all soft tissue sarcomas. In European countries and the United States, the frequency of their occurrence is 3.4 cases per year per 1 million children under 15 years of age, in Kazakhstan - 0.6-1.2 cases per 1 million child population. Rapid tumor growth, malignancy and early metastasis to other organs and systems predetermines its special role in oncology. Objective of the study: to improve the quality and availability of early diagnosis of sarcomas in children in medical institutions of the general medical network. Results of the study: 35 cases of peripheral PNET in children were analyzed. The age of the patients is from 1.5 to 17 years. The average age is 9.3 years. There were 1.3 times more boys among patients than girls. Extra-skeletal localization was found in one patient (3.6%). Radiographically, it is often almost impossible to make a differential diagnosis between the manifestations of Ewing's sarcoma and primary chronic or "healed" (antibiotic) forms of acute hematogenous osteomyelitis in the initial phase of the process, before the formation of the extraosseous soft tissue component. The process of bone damage is more often localized in its diaphysis and subsequently spreads to the metaphyses of the bone.

Skull Base Osteomyelitis: A Comprehensive Imaging Review.

Skull base osteomyelitis is a relatively rare condition, generally occurring as a complication of advanced otologic or sinus infection in immunocompromised patients. Skull base osteomyelitis is generally divided into 2 broad categories: typical and atypical. Typical skull base osteomyelitis occurs secondary to uncontrolled infection of the temporal bone region, most often from necrotizing external otitis caused by Pseudomonas aeruginosa in a patient with diabetes. Atypical skull base osteomyelitis occurs in the absence of obvious temporal bone infection or external auditory canal infection. It may be secondary to advanced sinusitis or deep face infection or might occur in the absence of a known local source of infection. Atypical skull base osteomyelitis preferentially affects the central skull base and can be caused by bacterial or fungal infections. Clinically, typical skull base osteomyelitis presents with signs and symptoms of otitis externa or other temporal bone infection. Both typical and atypical forms can produce nonspecific symptoms including headache and fever, and progress to cranial neuropathies and meningitis. Early diagnosis can be difficult both clinically and radiologically, and the diagnosis is often delayed. Radiologic evaluation plays a critical role in the diagnosis of skull base osteomyelitis, with CT and MR imaging serving complementary roles. CT best demonstrates cortical and trabecular destruction of bone. MR imaging is best for determining the overall extent of disease and best demonstrates involvement of marrow space and extraosseous soft tissue. Nuclear medicine studies can also be contributory to diagnosis and follow-up. The goal of this article was to review the basic pathophysiology, clinical findings, and key radiologic features of skull base osteomyelitis.

Radiation diagnosis of peripheral&#x0D; primitive neuroectodermal tumors&#x0D; (PNET) in children under&#x0D; the conditions of the scientific center of&#x0D; pediatrics and pediatric surgery&#x0D; (Almaty, Kazakhstan)

Relevance: Peripheral primitive neuroectodermal tumor (PNET) belongs to the group of malignant tumors that&#x0D; develop from migrating embryonic neural crest cells. PNET&#x0D; includes several nosological forms: Askin’s tumor, esthesioneuroblastoma, the very peripheral primitive neuroectodermal tumor, and Ewing’s sarcoma [1]. PNET accounts&#x0D; for 3–9% of all soft tissue tumors and 19% of all soft tissue&#x0D; sarcomas in children [2, 3]. In Europe and the US, PNETs account for 3.4 cases per year per 1 million children below 15&#x0D; years; in Kazakhstan – 0.6-1.2 cases per 1 million child population. Rapid tumor growth, malignancy, and early metastasis to other organs and systems predetermine the PNET’s&#x0D; specific role in oncology [4].&#x0D; The purpose was to improve the quality and availability of early sarcoma diagnostics in children in medical institutions of the general medical network.&#x0D; Results: 35 cases of peripheral PNET in children were analyzed. The age of the patients was 1.5 to 17 years, the average age – 9.3 years. Boys were 1.3 times more than girls. One&#x0D; patient (3.6%) had extra-skeletal tumor localization. Children with stage IIB prevailed – 46.4% of cases (13 children).&#x0D; Radiographical differentiation between Ewing’s sarcoma and primary chronic or “healed” (antibiotic) acute&#x0D; hematogenous osteomyelitis in the initial phase of the process is almost impossible before the extraosseous soft tissue&#x0D; component is formed. The bone damage process is more&#x0D; often localized in the bone diaphysis and subsequently&#x0D; spreads to its metaphyses.&#x0D; Conclusion: PNET originates most often from the chest&#x0D; wall, so it is advisable to start the X-ray examination from&#x0D; the chest. In terms of radiation semiotics, PNET is similar to&#x0D; Ewing’s sarcoma and Askin’s tumor; therefore, an additional&#x0D; immunohistochemical study of the tumor tissue is required.&#x0D; An important indirect diagnostic criterion in Ewing’s sarcoma&#x0D; is the predominance of the soft tissue component over the&#x0D; bone manifestations. Extended CT and MRI studies with contrast enhancement (chest, abdominal cavity, pelvis, and the&#x0D; primary lesion area) and skeletal scintigraphy are required to&#x0D; clarify the extent of changes, stage the tumor accurately, and&#x0D; assess the tumor dynamics after treatment. The above conclusions generally coincide with the available literature data.

Radiation diagnostics of peripheral primitive&#x0D; neuroectodermal tumors (PNET)&#x0D; in children at the Scientific Center&#x0D; of Pediatrics and Pediatric Surgery&#x0D; (Almaty, Kazakhstan)

Relevance: Peripheral primitive neuroectodermal tumor (primitive neuroectodermal tumor – PNET) belongs to the group&#x0D; of malignant tumors that develop from migrating embryonic neural crest cells. PNET includes several nosological forms: Askin’s&#x0D; tumor, esthesioneuroblastoma, the very peripheral primitive neuroectodermal tumor, and Ewing’s sarcoma. PNET accounts for&#x0D; 3–9% of all soft tissue tumors and 19% of all soft tissue sarcomas in children. In Europe and the US, PNETs account for 3.4 cases&#x0D; per year per 1 million children below 15 years; in Kazakhstan – 0.6-1.2 cases per 1 million child population. Rapid tumor growth,&#x0D; malignancy, and early metastasis to other organs and systems predetermine the PNET’s specific role in oncology.&#x0D; The purpose of the study was to improve the quality and availability of early sarcoma diagnostics in children at medical&#x0D; institutions of the general medical network.&#x0D; Results: 35 cases of peripheral PNET in children were analyzed. The age of the patients was 1.5 to 17 years, the average age –&#x0D; 9.3 years. Boys were 1.3 times more than girls. One patient (3.6%) had extra-skeletal tumor localization. Children with stage IIB&#x0D; prevailed – 46.4% of cases (13 children).&#x0D; Radiographical differentiation between Ewing’s sarcoma and primary chronic or “healed” (antibiotic) acute hematogenous&#x0D; osteomyelitis in the initial phase of the process is almost impossible before the extraosseous soft tissue component is formed.&#x0D; The bone damage process is more often localized in the bone diaphysis and subsequently spreads to its metaphyses.&#x0D; Conclusion: PNET is more likely to come from the chest wall, so it is advisable to start the X-ray examination from the chest.&#x0D; In terms of radiation semiotics, PNET is similar to Ewing’s sarcoma and Askin’s tumor; therefore, an additional immunohistochemical study of the tumor tissue is required. An important indirect diagnostic criterion in Ewing’s sarcoma is the predominance of the soft tissue component over the bone manifestations. Extended CT and MRI studies with contrast enhancement&#x0D; (chest, abdominal cavity, pelvis, and the primary lesion area) and skeletal scintigraphy are required to clarify the extent of&#x0D; changes, stage the tumor accurately, and assess the tumor dynamics after treatment. The above conclusions generally confirm&#x0D; the available literature data.

Image-guided core needle biopsy for Ewing sarcoma of bone: a 10-year single-institution review.

To evaluate the performance of image-guided core needle biopsy (IGCNB) for the diagnosis of Ewing sarcoma of bone. All patients with a confirmed diagnosis of Ewing sarcoma who underwent IGCNB between January 2007 and December 2016 were included in this retrospective study. Analysis included mean age, skeletal distribution, imaging modality used for biopsy guidance, type of anaesthesia, needle type, number of passes, type of tissue sampled, and complications. The study included 139 patients (94 males and 45 females; mean age 18.7years) who underwent 141 image-guided core needle biopsies as the primary diagnostic test. Of these, 101 were CT-guided, 38 ultrasound-guided, and 2 utilised both CT and ultrasound guidance. A total of 97.9% were diagnostic at first procedure. Of the 3 non-diagnostic cases, 2 underwent a further IGCNB and were positive, while 1 patient required an open surgical procedure. Only 1 patient (0.7%) suffered an immediate complication, and there were no recorded delayed complications. IGCNB is a safe procedure providing a positive diagnosis of Ewing sarcoma of bone in a very high percentage of cases. It should be the first-line method for establishing a diagnosis in suspected Ewing sarcoma of bone. • Image-guided core needle biopsy is a safe procedure providing a positive diagnosis of Ewing sarcoma of bone in a very high percentage of cases. • Image-guided core needle biopsy should be the first-line method for establishing a definitive diagnosis in Ewing sarcoma and should be performed at a specialist sarcoma referral centre. • When technically feasible, extra-osseous soft tissue alone can be sampled with confidence as there is no difference in diagnostic performance whether bone or an extra-osseous soft tissue component of the tumour is sampled.

Can MRI differentiate between atypical cartilaginous tumors and high-grade chondrosarcoma? A systematic review

Background and purpose — Adequate staging of chondroid tumors at diagnosis is important as it determines both treatment and outcome. This systematic review provides an overview of MRI criteria used to differentiate between atypical cartilaginous tumors (ACT) and high-grade chondrosarcoma (HGCS).Patients and methods — For this systematic review PubMed and Embase were searched, from inception of the databases to July 12, 2018. All original articles describing MRI characteristics of pathologically proven primary central chondrosarcoma and ACT were included. A quality appraisal of the included papers was performed. Data on MRI characteristics and histological grade were extracted by 2 reviewers. Meta-analysis was performed if possible. The study is registered with PROSPERO, CRD42018067959.Results — Our search identified 2,132 unique records, of which 14 studies were included. 239 ACT and 140 HGCS were identified. The quality assessment showed great variability in consensus criteria used for both pathologic and radiologic diagnosis. Due to substantial heterogeneity we refrained from pooling the results in a meta-analysis and reported non-statistical syntheses. Loss of entrapped fatty marrow, cortical breakthrough, and extraosseous soft tissue expansion appeared to be present more often in HGCS compared with ACT.Interpretation — This systematic review provides an overview of MRI characteristics used to differentiate between ACT and HGCS. Future studies are needed to develop and assess more reliable imaging methods and/or features to differentiate ACT from HGCS.

MON-434 Encapsulated Follicular-Variant of Micropapillary Carcinoma Presenting with Distant Bony Metastasis

INTRODUCTION The incidence of thyroid cancer has risen steadily over the last decades, in part due to increasing diagnosis of apparently low-risk well-differentiated cancers. The outcomes of well-differentiated thyroid cancers, including follicular variant papillary thyroid carcinoma (PTC), are believed to be quite favorable, with a largely indolent benign course. We examine an encapsulated follicular-variant of micropapillary carcinoma presenting with distant bony metastasis. CASE 55-year-old lady presented to clinic after biopsy of iliac crest (IC) mass revealed thyroid tissue. One year prior she started having dull pain at right hip, attributed to increased physical activity. She noticed a tender “lump” on her right hip. CT revealed destructive right iliac 8 cm mass with extraosseous soft tissue component, central necrosis, and eccentric calcifications; and right ovarian cyst. Right IC biopsy was consistent with thyroid tissue with positive Thyroglobulin and TTF-1 immunostains. Physical exam was normal, except for mild tachycardia, hypertension, right flank large rounded mass fixed to IC, tender to palpation without erythema or warmth on overlying skin. Thyroid ultrasound showed normal thyroid gland except 5.58 x 6.22 x 7.76 mm left lobe nodule without increased vascularity but with coarse peripheral calcification. FNA was unsatisfactory. Thyroid function tests revealed undetectable TSH, elevated FT4, FT3, and markedly elevated thyroglobulin and TSI. PET/CT scan showed focal area of mild FDG avidity, corresponding to the right iliac crest mass, without additional areas of FDG avidity suggestive of metastatic disease or primary neoplastic process. Three weeks after presentation, patient began having symptoms of hyperthyroidism. As FT4 and FT3 continued to rise, she was started on propranolol and methimazole. Due to inadequate response, methimazole was switched to high dose propylthiouracil with mild improvement. Thyroid uptake and scan and SPECT-CT revealed increased thyroid uptake and thyromegaly consistent with Graves’ disease and redemonstrated large right IC lesion with increased uptake in the periphery and central photopenia, suggesting metastatic thyroid malignancy. Pathology from total thyroidectomy reported encapsulated follicular variant of PTC, confined to the left lobe of the thyroid, without extrathyroidal extension, greatest tumor dimension 0.6cm. As metastasis to the IC were unlikely to have originated from this small encapsulated thyroid cancer, it was recommended to proceed with right oophorectomy for suspected malignant struma ovarii and IC lesion debulking. Surgical pathology revealed right ovary and fallopian tube without pathologic changes or features of teratoma and tissue from right iliac mass consistent with PTC. Patient is off all antithyroid medications and remains biochemically euthyroid, awaiting radioactive iodine therapy.