Case Report Elmer Press J Clin Med Res • 2010;2(4):185-188 Cutaneous Granular Cell Tumor of the Breast: A Clinical Diagnostic Pitfall Jose Aneiros-Fernandeza, d, Salvador Arias-Santiagob, Husein Husein-ElAhmedb, Francisco O’Vallea, Maria Ines Aroca Siendonesc, Jose Aneiros-Cachazaa Abstract We report the clinical-morphological study of a granular cell tumor in dermal/hypodermal junction and subcutaneous fat left breast of an 83-year-old woman with a family history of breast carcinoma. Mammography study showed a spiculated lesion in the lower inner quadrant with suspicion of malignancy. The results of fine needle puncture-aspiration were inconclusive. Subsequent tumorectomy revealed a poorly-defined indurated lesion of 1.1 x 0.7 cm. The his- topathology study showed a proliferation of cells with ample and granular cytoplasm that were positive for S100, CD 68 and inhibin and negative for hormonal receptors. We present a benign lesion that clinically reproduces a breast carcinoma. Keywords: Granular cell tumor; Breast; Differential diagnosis; Cutaneous Introduction Granular cell tumor (GCT) is a rare benign neoplasm of soft tissues of probable peripheral nervous tissue or Schwann cell origin. The most frequent site is the tongue (40% of cases), but it has been reported in various localizations (skin and visceral). In around 5% - 6% of cases GCT is observed in the breast [1], where it can be clinically and radiologically confused with a malignant breast tumor. Manuscript accepted for publication July 1, 2010 aDepartment of Pathology, University Hospital, Granada, Spain bDepartment of Dermatology, University Hospital, Granada, Spain cDepartment Coordination of Tumor Bank Network Andalucia, San Cecilio University Hospital, Spain dCorresponding author: Department of Pathology, University Hospital, Granada, Spain. Avd. Madrid S/N. CP: 18012. Email: janeirosf@hotmail.com doi:10.4021/jocmr403w We report a case of GCT of the breast in an 83-year- old woman with clinical and radiology findings that mimic breast carcinoma, contributing clinical-morphological data on a lesion at an uncommon site. Case Report A 83-year-old woman presented with an abnormality de- tected by screening mammography three months earlier. Her mother and sister had a history of breast cancer. Physical ex- amination revealed a painless palpable mass of around 1 cm in the lower inner quadrant of the left breast, with no skin alteration or nipple discharge. Mammography showed an ill-defined, high-density spiculated mass of 1 cm in left inner breast (Fig. 1). No as- Figure 1. Mammography showed an ill-defined, high-density spiculated mass. Articles © The authors | Journal compilation © J Clin Med Res and Elmer Press™ | www.jocmr.org 185