Spontaneous cutaneous squamous cell carcinoma in a sooty mangabey (Cercocebus atys): a case report.

An adult sooty mangabey (Cercocebus atys) with a solid mass arising from the skin of the dorsolateral cervical area was presented to the veterinary clinical staff. Grossly, the mass was firm, elongated, ulcerated at the tip, and measured 2.7 x 2.0 x 2.3 cm. It was surgically excised and then submitted for histopathologic evaluation. On histopathology, this tumor was composed of irregular masses and cords of neoplastic squamous epithelial cells that invaded the dermis and subcutis, often undergoing keratinization and forming numerous keratin pearls. On the basis of these histologic findings, the mass was diagnosed as a squamous cell carcinoma. Additional tests, including hematologic evaluations and radiographic views of the abdominal, thoracic, and cervical areas, were normal. Sections of the tumor were analyzed by electron microscopy and showed no evidence of viral particles. To the authors' knowledge, this is the first reported case of a spontaneous cutaneous squamous cell carcinoma in a sooty mangabey.