Introduction: Primary sinovial sarcoma (PSS) is a very rare malignancy in lung, although lung is the most common organ-based site for metastatic synovial sarcoma. It is a high grade malignant mesenchymal neoplasm showing variable epithelial differentation and characterized by a balanced translocation t(X, 18). Case report: We report a case of a 67- year-old male presented with long lasting cough, chest pain and fever. Chest radiography and computer tomography scan revealed a large well defined lung mass invading hilum of the lung, which was indicated for the lung resection. Histopatological examination showed high-cellulare spindle cell malignant tumor. Immunohistochemically,neoplastic cells were positive for vimentin, TLE-1, Bcl-2, focally positive for cytokeratin AE1/AE3, cytokeratin 7, cytokeratin 18, cytokeratin 19, EMA, calponin and negative for CK 5/6, S100, STAT6, CD34, SMA, Desmin, CD99 and CD 117, which determinate a diagnosis of monophasic PSS of lung. Specific translocation t(X, 18) was detected by fluorescent in situ hybridization (FISH). Conclusion: Diagnosis of PSS in lung may create various diagnostic challenges. It can be established only after exclusion of metastatic sarcoma of other localizations and spindle cell primary lung malignancies. Molecular testing proved to be very helpful or necessary when spindle cell synovial sarcoma was recognized in uncommon sites.

Introduction: Hyperostosis frontalis interna is progressive, irregular thickeness of the frontal bone s internal table. It has been associated with a wide range of syndromes, though we know now that it can occur as an independent entity. Etiology is still unclear, but the most probable hyphothesis is alteration of steroid sex hormons, proven in high frequency among postmenopausal women. It is mostly asympthomatic or it has been accidentally diagnosed after endocranial trauma or postmortal. Because of its progression, in some cases it can cause cerebral cortical compression and varible neurological symptoms. Case report: We present a case of 27 years-old women, hospitalized in Neurosurgical Clinic, because of severe headaches lasting for 3 month. The head CT scan showed a massive, expansive lesion in right frontal bone, with spearing of the superior sagittal sinus and skull midline. Bone bulging does not affect outer table of the frontal bone, but only diploic space and inner table. Pathological analysis of the frontal bone showed marked trabecular thickening both cortical and spongy bone, with corticalisation of spongy bone. Haversian canals showed reduction in number and size, and light fibrosis. The lamellas of the spongy bones were enlarged, with prominent interlamellar bridges and the reduction of interlamellar spaces.In purpose of closer determination of etiopathogenesis,we did immunohystochemical analysis of Estrogen, Progesteron and Androgen receptors in dural tissue. Immunohistohemical stain confirmed nuclear expression of Estrogen and Androgen receptors in dural fibroblasts.Progesterone receptors were negative on immune stain. Conclusion: These results could support the hormonal theory of the cause of hyperostosis frontalis interna.

Introduction: GD is the commonest lysosomal storage disease worldwide. The majority of the patients have Type1 GD which is the non-neuronopathic form of disease. There are data of increased risk of cancer in GD patients, such as: multiple myeloma and other haematological malignancies, hepatocellular carcinoma and renal carcinoma. Factors of cancerogenesis in GD are accumulation of bioactive lipids, alternatively activated macrophages, immune dysregulation, genetic modifiers underlying the GD, splenectomy and enzyme replacement therapy. Extra-osseous soft tissue masses are described in GD patients, like localised deposition od Gaucher macrophages (Gaucheroma). To the best of our knowledge, no other case of extra-osseous soft tissue sarcoma in association with GD has been described in literature. To present very rare case of high grade leiomiosarcoma in association with Gaucher disease (GD). Case report: The case concerns 81 years old female with leucopenia and thrombocytopenia since year 2000. In 2014 she was diagnosed with undifferentiated pleomorphic sarcoma with prominent inflammation on her thigh, which was not completely surgically removed. She was diagnosed with leucopenia, thrombocytopenia and splenomegaly in 2014 on control examination. Bone marrow biopsy was performed and histologically and immunohistochemically was diagnosed GD. The diagnosis was confirmed by enzyme activity test. In 2018 revision of pathohistological finding of thigh tumour was performed. High grade leiomiosarcoma was diagnosed. She is alive and refuses any treatment. Conclusion: GD is rarely diagnosed in older age. All soft tissue masses in GD should be carefully examined because of increased risk of cancer in GD patients.

Aim: We present the case of a rare localization of the alveolar soft part of the sarcoma in the visceral organ. Introduction: Alveolar soft part sarcoma (ASPS) is a rare mesenchymal tumor typically occurring in young patients, more frequently in females. Common localization of ASPS is skeletal musculature of lower extremities. ASPS in visceral organs usually represents a metastasis from the more common primary location in skeletal muscles. ASPS is characterized by a tumor-specific translocation which causes the fusion of the TEF3 with a ASPL gene (also known as ASPSCR1). Case report: Female 47 years old was admitted to hospital due to abdominal pain. Urgent surgery was performed due to ileus. Ileal tumor was detected intraoperatively as a cause of ileus. Tumor was infiltrated whole intestinal circumference, with dimension 70mm x 47cm and evident perforation. Histology showed well-defined nests of pleomorphic cells separated by delicate fibrovascular septae. Within described nests there is a prominent lack of cellular cohesion, representing for the distinctive pseudoalveolar pattern. Immunohistochemical stadies were diffusely positive for TFE3 and focally positive for CD34 and alpha-SMA and negative for panCK, DOG-1, CD117, S-100, HMB45, Desmin. Immunopositivity for Ki67 was present in 20% of tumor cells. FISH analysis was done using locus specific dual color break-apart TFE3 (3 and 5 ) probe and rearrangement in the TFE3 gene was confirmed. Conclusion: Despite the fact that ASPS is rare mesenchymal tumor in visceral organs it have to be considered as possible diagnosis especially in cases with typical histological features and immunohistochemical profile. Definitive diagnosis of ASPS must be confirmed by FISH analysis.

Aim: We present a rare case of gastrointestinal tumor in a boy. Introduction: Gastrointestinal stromal tumors (GISTs) represent rare mesenchymal tumors in pediatric population. Most of these tumors originate in the stomach and very rarely in the oesophagus. They are more frequent in young girls. As opposed to adult GISTs, those that occur in childhood show mutations in PDGFRA receptors or so called “Wild type” mutations. Case report: A fifteen years and 2 months old boy with symptoms of dysphagia and stenocardia for the last six months. Endoscopy showed nodular solid lesion at the distal part of the thoracal oesophagus, later surgically removed. Dimensions of the lession were 35x25x20mm with whitishPOSTER SESIJA 57 MATERIA MEDICA • Vol. 34 • Issue 1, suplement 1 • april 2018. yellow cut surface and areas of hemorrhage. Histology showed predominant spindle cell pattern with minor epithelioid component, with pronounced cellular and nuclear pleomorphism, rare areas of necrosis and hemorrhage, with the mitotic count more than 18 per 50 high power fields and numerous atypical mitotic figures. Immunohistochemical studies were CD117 and DOG-1 negative, but positive for PDGFRA. Tumor expressed focal alpha-SMA and CD34 positivity. Conclusion: Informations regarding pediatric gastrointestinal stromal tumors are still insufficient. Even though these tumors are rare in childhood, when analysing mesenchymal neoplasms potential GISTs should be considered.