Sinonasal Fibrosarcomas, Malignant Schwannomas, and "Triton" Tumors. A Clinicopathologic Study of 67 Cases

Background: Sinonasal fibrosarcomatous neoplasms are uncommon tumors and there are no previous studies of a large number of such cases. The clinical and histologic features of 67 fibrosarcomatous neoplasms of the nasal cavity and paranasal sinuses are reported.

Methods: Multiple clinical and histologic parameters (including immunostain results) were analyzed to characterize the features important for histologic recognition of the tumors and for correlation with patient outcomes.

Results: Some tumors could be classified as malignant schwannomas or malignant "Triton" tumors, but their behavior was similar to that of the fibrosarcomas. Histologically, most tumors were very low-grade malignant neoplasms; however, 22% of patients died of their tumors. Factors that correlated with death were mitotic rate (greater than 4 mitoses per 50 high-power fields), increased tumor cellularity, and male sex.

Conclusions: Many tumors originally were diagnosed as benign (by others), probably causing initial undertreatment of some patients. Proper recognition and histologic evaluation of the tumor are important to ensure the best therapy and optimal patient survival.