Fig. 3.

Histologic features of the tumor. a Low power appearance showing, in this portion of the tumor, thick fibrous septae separating sheets of neoplastic cells with no appreciable “alveolar” pattern. b Tumor cells with small, ovoid nuclei and granular cytoplasm, simulating granular cell tumor. c Tumor cells with large nuclei with open chromatin and prominent nucleoli, ample clear to faintly eosinophilic cytoplasm, and intracytoplasmic granular eosinophilic material. d PAS stain after diastase digestion showing positivity of the cytoplasmic granules