•An alveolar soft part sarcoma case mimicking malign melanoma and renal cell carcinoma

Abstract

Alveolar soft part sarcoma is a rare, distinctive sarcoma most frequently encountered in patients 15-35 years of age, and typically located in the deep soft tissues of the lower extremities in adults. If the tumor affects infants and children, it is often located in the head and neck region. This uncommon neoplasm presents as a slowly growing, painless mass. Because of relative lack of symptoms, it could be easily overlooked and frequent late metastases might be seen at the time of diagnosis after a prolonged clinical course. Herein, we reported an alveolar soft part sarcoma case occurred in a 64 year old male patient with the complaint of a slowly growing mass on his right glutea. The operation specimen was a poorly circumscribed soft tissue and cut section was gray-white with areas of hemorrhage and nescrosis. On light microscopic investigation, the histological picture reminiscent of alveolar soft part sarcoma with celslular tumoral lesion in an organoid patern, and malignant melanoma like morphology somewhere in the tumor were observed. Immunohistochemical staining revealed posistivity with vimentin, S-100, EMA, Pankeratin and CD68, but negativity with HMB 45, Melan A, CD 10, sinaptofisin and chromogranin A in the tumor cells. Although immunoshistochemical findings were not specific, the histopathoslogical picture was appropriate for the diagnosis. In conclusion, despite the relatively slow growth, the ultismate prognosis is poor so it is very important to recognize this malign lesion with an unexpected clinical presentation and distinct immunohistomorphological features exist.