Collision tumor of maxilla: a diagnostic dilemma.

Most malignant tumors arise from the primary tissue except when showing extreme dedifferentiation. This can be identified by examination of tumor cells and their products. Occasionally two distinct tissues are recognized within a malignant tumor. In mixed malignant tumors both carcinomatous and sarcomatous elements are present either because of simultaneous malignant change occurring in the epithelium and its nonepithelial stroma or there is a sarcomatous transformation of stroma of a carcinoma. Willey's in 1960 stated that in these circumstances the resulting tumor must be classified as a "carcino-sarcoma". These separate tumors arise in nearby structures and may grow to infiltrate in each other resulting in a tumor mass. The present article is a report of a diagnostic dilemma in an extremely rare carcinosarcoma of maxilla in a 24 year old male which was first on biopsy reported as odontogenic myxoma. After resection (right maxillectomy under GA using Weber Fergusons approach with Diffenbach's extension) was diagnosed as Squamous Cell Carcinoma arising from lining of the maxillary antrum associated with Osteogenic Sarcoma (chondroblastic differentiation) of maxilla with negative margins. The tumor was restaged to T2NoMx and further managed as per National Comprehensive Cancer Network Guidelines. Immunohistochemistry later re-diagnosed it to be an Osteogenic Sarcoma maxilla with chondroblastic differentiation. 'T' stage remains the most reliable predictor of survival and loco-regional control. Complete surgical resection for all 'T' stages (except T4b, any N) followed by postoperative therapy remains a corner stone of treatment of maxillary sinus tumors.