Atypical Granular Cell Tumor-Apropos of a Case With Indeterminate Malignant PotentialMahoney, Anne BA; Garg, Amit MD; Wolpowitz, Deon MD, PhD; Mahalingam, Meera MD, PhD, FRCPathAmerican Journal of Dermatopathology: June 2010 - Volume 32 - Issue 4 - pp 370-373 doi: 10.1097/DAD.0b013e3181be99e3 Extraordinary Case Report Abstract Author Information Malignant granular cell tumor is relatively uncommon, constituting 1%-2% of all granular cell tumors. We describe a case of a 53-year-old woman who presented with a 4.5 × 5.5-cm nodule on her left lower abdomen. An initial punch biopsy revealed a pandermal infiltrate of epithelioid cells with finely granular cytoplasm and vesicular nuclei-histologic features consistent with a granular cell tumor. Given the large size of the neoplasm, an excisional biopsy was recommended that revealed in addition to the above, focal ulceration, epithelioid cells with vesicular nuclei and prominent nucleoli, increased mitotic activity, pleomorphism, and epidermotropism with pagetoid spread-features that were histologically concerning for malignant transformation. We present this case to increase awareness of an uncommon entity and to emphasize the pitfalls associated with incomplete removal and an inadequate biopsy. From the *Boston University School of Medicine; †Department of Dermatology; and ‡Dermatopathology Section, Department of Dermatology, Boston University School of Medicine, Boston, MA. Reprints: Amit Garg, MD, Department of Dermatology, Boston University School of Medicine, 609 Albany St, J-Bld, Boston, MA 02118 (e-mail: firstname.lastname@example.org). Copyright © 2010 Wolters Kluwer Health, Inc. All rights reserved.