Trichoblastic carcinosarcoma: A case report and literature review.

Trichoblastic carcinosarcoma is a rare biphasic adnexal neoplasm. This case report chronicals the eighth occurrence of this tumor published in the English literature and provides a review of the prior publications. Clinically, this tumor presents as an isolated, rapidly growing lesion in elderly patients and is usually cured by complete surgical excision, with no evidence of recurrence or metastasis at follow-up (7/8 cases). Histopathologically, trichoblastic carcinosarcoma is dermal-based, with an epithelial component of basal cells and a mesenchymal component of spindle cells, both of which display malignant features. In addition to a morphologic description of trichoblastic carcinosarcoma, a discussion of the differential diagnoses, including other biphasic neoplasms, is also included. The small number of cases of trichoblastic carcinosarcoma is most likely secondary to under-recognition and underreporting and a larger case volume is needed to more accurately assess the clinical course and treatment strategies.