Monophasic synovial sarcoma of tongue.

Synovial sarcoma is a well defined morphologic entity extensively researched in literature. Synovial sarcoma displays a wide spectrum of clinical presentations and histologic appearances that may give rise to diagnostic dilemmas. One such unusual site in the head and neck area is the tongue. We report a case of monophasic synovial sarcoma of the tongue in a 22-year-old male. Microscopically, this tumor mimicked a poorly differentiated carcinoma which is more common at this site though the patient was young for this type of tumor. On immunohistochemistry, neoplastic cells were positive for cytokeratin, vimentin, calponin, CD99 and bcl2. Molecular studies - viz. reverse transcriptase polymerase chain reaction revealed a SYT-SSX translocation clinching the diagnosis. This paper highlights the immunohistochemistry profile and SYT-SSX translocation which helped arrive at an accurate diagnosis only because the index of suspicion for a monophasic synovial sarcoma is high.

Solitary fibrous tumour: a diagnostic dilemma.

Solitary fibrous tumour (SFT) is a rare spindle cell neoplasm arising at pleural and extrapleural sites. Five cases of SFT diagnosed at our institution over a five year period were reviewed. Haematoxylin and eosin stained histological sections, immuno-histochemical markers including CD34 and electron microscopy were the different methods used to study these tumours. Three histological features were consistently observed in all the tumours: the tumours were composed of short spindle cells separated by dense collagen bands and arranged in alternate hypocellular and hypercellular areas. CD34 positivity was seen in all the cases. SFT's have been reported to behave in an unpredictable fashion and hence prolonged follow up is essential. Histology, CD34 positivity and electron microscopy are useful tools in diagnosing SFT. While the pleural tumours can be diagnosed based on histology, this must be substantiated by ancillary techniques in case of extrapleural tumours.

Rosette formation in osteosarcoma.

Rosette formation is a rare, recently reported variation in osteogenic sarcoma and is thought to be associated with a poor prognosis. We report two cases of rosette forming osteosarcoma, one with poor response and other with total necrosis following chemotherapy. Pathologists should be aware of rosette formation in osteosarcoma to avoid misdiagnosis as other rosette forming tumors of bone especially PNET/Ewings sarcoma. In our opinion rosettes in an osteosarcoma should be documented both from a differential diagnostic point of view and also to elucidate definitive prognostic implications.