PMC9935962_01
A granular cell tumor involving the left axillary accessory breast in a 50-year-old woman.. A. Mammography shows an isodense mass with a well-circumscribed margin adjacent to the skin layer in the left axillary region (arrow).. B. Ultrasonography shows a round hypoechoic mass with a well-circumscribed margin and non-parallel orientation and echogenic halo.. C. Photomicrograph of a histopathological specimen shows nests of large cells with granular eosinophilic cytoplasm containing typical small nuclei (hematoxylin & eosin stain, x 200).. D. Immunohistochemical analysis of the resected specimen shows cells with immunopositivity for the S-100 protein (x 100).
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F1
A circumscribed, round, and isodense mass that had not been observed 2 years earlier on mammography was discovered in the left axillary region on a recent mammogram (Fig. 1A). US examination of the axilla revealed a 1.1 cm, non-parallel, round, hypoechoic mass with a circumscribed margin and an echogenic halo (Fig. 1B). A surgical specimen showed tumor cells with a distinctive granular eosinophilic cytoplasm associated with typical nuclei, without an increase in nuclear division or another sign of malignancy (Fig. 1C). IHC analysis of the tumor showed strong S-100 positivity, CD68 positivity, and pancytokeratin negativity (Fig. 1D).