Giant metatypical carcinoma: An unusual tumor

Metatypical carcinoma (MTC) or basosquamous carcinoma is a remarkable malignancy with features of both basal and squamous cell carcinoma. It is typically located on the back and face, often with clinical features of basal cell carcinoma but tending to be more aggressive with enhanced prospects of lymph node or distant metastases. Our report describes a huge neglected MTC of the back of ten-year duration, a giant ulcero-vegetative tumor measuring 20x25 cm. Histologic examination of specimens from the margins and periphery revealed aspects of both basal and squamous cell carcinoma, while the ulcerated center showed sclerotic tissue without tumor. Radical excision and reconstruction by grafts were performed. No metastases were observed after two years. There are many controversies surrounding the histologic definition and biologic behavior of MTC, including its metastasizing potential. The MTC we describe exhibited benign biologic behavior. This may have been related to an intense inflammatory host response with elimination of neoplastic tissue and consequent local sclerosis evident in the central tumor-free portion. This central tumor regression is to our knowledge a unique finding in MTC.