Abstract
Background : Granular cell tumors (GCT) are uncommon and usually benign tumor, considered to be of Schwann cell origin. Primary GCT of the breast is exceedingly rare, accounting for 5% of all cases of GCT. We report a case of breast GCT having numerous intranuclear cytoplasmic inclusions.
Case : A 52-year-old woman reporting a nodule of the right breast was suspected of malignancy based on mammography and ultrasonography findings. Imprint smears from excised tumor tissue showed tumor cells in sheets or clusters or isolated cells and many naked nuclei against a granular background. Tumor cells had ill-defined abundant granular cytoplasm, round to oval small nuclei, conspicuous single small nucleli, and intranuclear cytoplasmic inclusions detected in 1.1% of tumor cells. Histologically, the tumor consisted of small nests or trabecular structures of polygonal cells with abundant eosinophilic granular cytoplasm. Granules were positive for periodic acid-Schiff (PAS) and diastase-resistant. Immunohistochemically, tumor cells were positive for S-100 protein and neuron-specific enolase.
Conclusion : The breast lesion showed typical cytological features of benign GCT with fragile, granular cytoplasm and intranuclear cytoplasmic inclusions.
