SMALL-CELL NEUROENDOCRINE CARCINOMA OF THE NASAL CAVITY AND PARANASALSINUSES

Small cell neuroendocrine carcinomas (SNECs) of the sinonasal tract ar e extremely uncommon tumors. We reviewed the clinicopathologic feature s of six cases of this neoplasm. There was no sex preponderance with t hree females and three males and a mean age at presentation of 51 pars (range, 38 to 68). Two patients had disease limited to the nasal cavi ty, and in four the tumor involved the nasal cavity and maxillary or e thmoid sinuses. involvement of the orbit was present in two patients. Surgery was the primary treatment. After a mean follow-up of 37 months , one patient died of local disease and liver metastases, four were al ive with recurrent or metastatic disease, and one died of unrelated ca uses. The tumors were composed of sheets, nests, and trabeculae with e xtensive areas of necrosis and hemorrhage. The individual cells were s mall to intermediate in size and had scanty cytoplasm. The nuclei were oval or round and hyperchromatic with absent or inconspicuous nucleol i. Nuclear molding and crush artefact were present in five cases. All tumors had a high mitotic rate with frequent abnormal mitotic figures. All cases stained for Cam 5.2, neuron-specific enolase, and chromogra nin. Five cases were positive for AE1:AE3, and four for synaptophysin. No case stained for S-100 protein, or neurofilaments. O-13 stained on e case. No case contained EBV-RNA. SNECs of the nasal cavity and paran asal sinuses are aggressive tumors with pathological features similar to those of anaplastic small cell carcinomas of the lung. They exhibit morphological and immunophenotypic features different from olfactory neuroblastoma and should be distinguished from this tumor. Copyright ( C) 1998 by W.B. Saunders Company.