Nasal polyposis with stromal atypia. Review of follow-up study of 14 cases.

The clinical, microscopical, and gross pathological features of 14 cases of intranasal and paranasal sinus polyposis with unusual stromal cell atypia are described. In gross appearance, the lesions were polypoid, translucent masses, similar to the usual nasal polyp. Although clinically the lesions were indicative of allergic and inflammatory nasal polyposis, microscopical examination showed numerous large, often pleomorphic histiocytes or facultative fibroblasts that were suggestive or sarcomatous, malignant degeneration. Diagnoses by the original contributing pathologists included embryonal rhabdomyosarcoma, stromal neoplasia, and juvenile masopharyngeal angiofibroma. Follow-up data showed no evidence of neoplasia, despite the remarkable cytological changes found in the stroma. The stromal atypia most likely represents a reactive phenomenon secondary to inflammation.