Granular cell basal cell carcinoma. A distinct histopathologic entity

Abstract

In 2 [human] cases of basal cell carcinoma with prominent granular cell features, light microscopic examination showed a tumor with the general configuration of a nodular basal cell carcinoma. Focally, there were masses of cells with eosinophilic, granular cytoplasm and large cytoplasmic inclusions, strongly suggestive of granular cell myoblastoma. Ultrastructural observations in 1 case showed numerous lysosome-like organelles that were similar to those described for granular cell myoblastoma, but were identical to those described for the granular cell variant of ameloblastoma, a tumor that frequently resembles basal cell carcinoma. Additional features included tonofilaments and desmosomes, which support an epithelial origin for the granular cells in this rare variant of basal cell carcinoma.