Cytomorphologic diagnosis of basaloid squamous cell carcinoma: a case report

Abstract

Background: Basaloid squamous cell carcinoma is a high-grade variant of squamous cell carcinoma that most commonly occurs in the upper aerodigestive tract. There are limited case reports of this entity in the cytology literature. The authors describe the cytologic features of a histologically confirmed case of basaloid squamous cell carcinoma arising in the floor of the mouth.

Case: A 51-year-old woman presented with a swelling in the floor of the mouth. Fine needle aspiration was performed; the aspirate comprised groups, sheets and a dispersed population of small to medium-sized cells with hyperchromatic nuclei and scant cytoplasm. Extracellular basement membrane-like material was also noted, which led to the erroneous diagnosis of adenoid cystic carcinoma. Histopathology characteristically revealed the presence of squamoid nests between malignant basaloid cells, and the tumor was finally diagnosed as basaloid squamous cell carcinoma. Occasional groups of squamoid cells were observed in the aspirate on retrospective evaluation.

Conclusion: Basaloid squamous cell carcinoma should be considered in the differential diagnosis of tumors arising in oral cavity. Cytologic diagnosis may be difficult, but careful search for a second cell population of squamoid cells in addition to small basaloid cells may aid in rendering the correct diagnosis.