Results: A lump (6 cm) was visible on the skin surface. Serial sectioning revealed solid gray-white tumor with cystic and prominent necrotic areas. The tumor was located in the deep mammary tissue an it infiltrated the overlying dermis without involving the epidermis. It consisted of atypical stelate and spindle cells with infrequent mitoses and low Ki-67 proliferative index. On the periphery mature adipocytes and lipoblasts were present. Stroma was abundant, myxoid with plexiform capillary pattern. The myxoid substance stained slightly Alcian-blue positive and tumor cells showed cytoplasmic immunopositivity for S100. Phylodes tumor was excluded because of absence of epithelial component. Conclusion: Myxoid liposarcoma has a distinct morphology, rarely confused with other soft tissue tumors, although on cytological smears or biopsy samples it may be unrecognized. Objective: Synovial sarcoma poses a difficult diagnostic challenge since it can be confused with other benign or malignant entities. Method: Four biphasic and one monophasic synovial sarcomas were studied. We used the break apart/split signal kit (VYSIS) to detect the t(X;18) translocation and we performed immunohistochemistry for TLE-1, INI-1, D2-40, CD56, CD99, bcl-2, EMA, CK7, CD34, S-100, Desmin and Claudin-1. Results: Immunohistochemically we observed: TLE-1+(5/ 5), INI-1 (4/5) with reduced nuclear and (1/5) with no expression, D2-40+(1/5), CD56+(5/5), CD99+(5/5), bcl-2 +(5/5), EMA focal expression (5/5), CK7−(5/5), CD34−(5/ 5), S-100−(5/5), Desmin−(5/5), Claudin-1 + (5/5). FISH revealed the split signal between the centromeric and telomeric end of the SYT gene. Conclusion: t(X;18) translocation remains the diagnostic hallmark of synovial sarcoma. INI-1 which is typically negative in atypical teratoid/rhabdoid tumor, epithelioid sarcoma and myoepithelial carcinoma seems to be reduced or even negative in synovial sarcomas. The focal expression of D2-40 must be considered when the differential diagnosis includes mesothelioma. Finally TLE-1 is a very sensitive marker for synovial sarcoma.