Basaloid squamous cell carcinoma of the sinonasal tract

BACKGROUND. Basaloid squamous cell carcinoma (BSCC) is a high grade, aggres sive Variant of squamous cell carcinoma with a predilection for the larynx, hypopharynx, tonsils, and base of the tongue. To the authors' knowledge, B SCC originating in the nasal cavity and paranasal sinuses rarely has been r eported. METHODS. Fourteen cases of BSCC involving the nasal cavity and paranasal si nuses were identified in the files of the Otolaryngic-Head and Neck Patholo gy Tumor Registry of the Armed Forces Institute of Pathology from 1975-1997 . Clinical records and follow-up were available in all cases. Paraffin bloc ks were available for histochemical and immunohistochemical studies in all cases. RESULTS. There were 7 females and 7 males, ages 32-86 years (median, 66.5 y ears; mean, 62 years). The patients presented primarily with a mass lesion and unilateral nasal obstruction. In nine patients the tumor was confined t o the nasal cavity. In three patients the tumor involved the sinuses alone and in two patients the tumor involved the nasal cavity and paranasal sinus es. Histologically, the tumors were widely invasive with a variety of growt h patterns, including lobular, solid, trabecular, cribriform, and fascicula r. The neoplastic infiltrate included predominantly pleomorphic, basaloid-a ppearing cells with hyper-chromatic nuclei, inconspicuous to prominent nucl eoli, and a variable amount of eosinophilic to clear-appearing cytoplasm. M itotic figures, including atypical forms, were readily apparent as was necr osis (individual cell and comedo-type). Foci of squamous differentiation we re limited in extent but were found in all cases and included squamous whor ls, individual cell keratinization, and intercellular bridges. Intraepithel ial dysplasia, carcinoma in situ, or invasive squamous carcinoma was presen t in all cases. Other histologic features included intercellular stromal hy alinization and peripheral nuclear palisading In two cases, neural-type ros ettes were found. Immunoreactivity for a variety of epithelial markers incl uding cytokeratin (AE1/AE3/LP34), CAM 5.2, 34 beta E12, CK7, and epithelial membrane antigen was present in all cases. Variable reactivity was present with vimentin, actins (smooth muscle and muscle specific), neuron specific enolase, S-100 protein, glial fibrillary acidic protein, CK20, carcinoembr yonic antigen, Leu7, and Ewing's marker. Chromogranin, synaptophysin, neuro fibrillary protein, leukocyte common antigen, HMB-45, desmin, and Epstein-B arr virus latent membrane protein were absent. Surgical resection was the t reatment of choice. Eight patients had recurrent or persistent tumor and me tastatic disease occurred in five patients. At last follow-up, 7 patients ( 50%) had died of disease with a median survival of 12 months from the time of diagnosis and 3 patients were alive with disease over periods ranging fr om 8 months-5 years. Of the 4 remaining patients, 2 were alive without dise ase at 1 month and 5 years, respectively, I patient was lost to follow-up w ith no evidence of tumor at 3 years, and 1 patient had died of unrelated ca uses with no evidence of disease. CONCLUSIONS. Sinonasal BSCC is a histologically distinct Variant of squamou s cell carcinoma with pathologic features and aggressive biologic behavior similar to BSCC localized to more common mucosal sites of the upper aerodig estive tract. (C) 1999 American Cancer Society.