[88] Expression of Epithelial Markers in Nodular Fasciitis and Fibromatosis: An Immunohistochemical Study.

Saba Yasir, Mehrdad Nadji, Paul Kurzawa, Gunlager P Nielsen, Andrews Rosenberg. University of Miami, Jackson Memorial Hospital, FL; Great Poland Cancer Centre, Poznan; Massachusetts General Hospital, Boston

Background: Myofibroblasts are distinct cell type and share morphological and functional characteristics with fibroblasts and smooth muscle cells. Immunohistochemically, they express myogenic antigens and have been documented to stain with epithelial markers. Myofibroblasts participate in a variety of disease processes and are the dominant cell type in specific tumor-like proliferations and neoplasms including reactive lesions, such as nodular fasciitis (NF), benign indolent and locally aggressive neoplasms such as dermatofibroma and fibromatosis, respectively, and low and high-grade myofibroblastic sarcomas. In viscera, subtypes of carcinomas have been identified that mimic benign myofiblastic lesions and because of the potential diagnostic pitfall that a keratin positive myofibroblastic tumor may introduce, we performed an immunohistochemical analysis to further explore the epithelial expression profile of well documented cases of nodular fasciitis and fibromatosis that arose in the soft tissues.
Design: Cases were identified from the surgical pathology files of Massachusetts General Hospital and consisted of resection specimens of 18 cases of nodular fasciitis and 20 cases of fibromatosis received between 2007 and 2010. A panel of 5 epithelial markers comprising CK-7, CAM5.2, AE1/AE3, P63 and estrogen receptor (ER) was performed on all cases. Cytoplasmic staining was assessed for the keratin antibodies and only nuclear immunoreactivity was considered positive for P63 and ER.
Results: Of eighteen cases of nodular fasciitis 9 were females (11-49 years) and 11 were males (5-69 years) with a mean age of 30.7 years (5-69 years). Of these eighteen cases 11 were located in upper extremity, 5 in head and neck, 1 in lower extremity and 1 in trunk. Of twenty cases of fibromatosis 14 were females (14-72 years) and 6 were males (15-28 years) with a mean age of 36.9 years (14-72 years). Of twenty cases 5 were located in lower extremity, 5 in trunk, 4 in shoulder, 3 in abdominal wall, 2 in buttocks and 1 in pelvis. All cases of nodular fasciitis (18/18) and fibromatosis (20/20) were negative for CK-7, CAM5.2, AE1/AE3, P63 and ER.
Conclusions: Nodular fasciitis and fibromatosis do not express epithelial immunohistochemical markers. Accordingly, a keratin positive tumor in which the differential diagnosis is between nodular fasciitis or fibromatosis and a variant of a spindle cell carcinoma is very unlikely to be one of these myofibroblastic proliferations.
Category: Bone & Soft Tissue

Monday, February 28, 2011 1:00 PM

Poster Session II # 3, Monday Afternoon


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