Urethral Caruncle: A Lesion Related to IgG4-Associated Sclerosing Disease?
Sean R Williamson, Marina Scarpelli, Antonio Lopez-Beltran, Rodolfo Montironi, Miriam R Conces, Liang Cheng. Indiana University, Indianapolis, IN; Polytechnic University of the Marche Region, Ancona, Italy; Cordoba University, Cordoba, Spain
Background: Urethral caruncle is a benign, polypoid urethral mass that occurs almost exclusively in postmenopausal women. Despite that these lesions have been long recognized and clinically managed with topical medications or excision, their pathogenesis is not well understood. In order to shed light on the etiology of urethral caruncle, we investigated the possibilities of autoimmune, viral, and inflammatory myofibroblastic proliferations as possible etiologies.
Design: In 38 patients with urethral caruncle, we utilized immunohistochemistry for immunoglobulin G (IgG), immunoglobulin G4 (IgG4) to assess for a potential autoimmune etiology. Immunohistochemistry was performed in nine patients for Epstein-Barr virus, BK virus, human herpesvirus 8, human papillomavirus, adenovirus, and anaplastic lymphoma kinase.
Results: Four patients (11%) showed infiltrates of ≥50 IgG4-positive plasma cells per high power field; all showed an IgG4:IgG ratio greater than 40%. One patient with increased counts below these thresholds had rheumatoid arthritis; none had documented autoimmune pancreatitis or other known manifestations of systemic IgG4-related sclerosing disease. All lesions showed negative reactions with the remaining markers of viral or inflammatory myofibroblastic etiologies.
Conclusions: Urethral caruncle is a benign inflammatory and fibrous polypoid urethral mass of unclear etiology. Using immunohistochemical markers, it appears unrelated to the viral infections that result in tumor formation and other mucosal abnormalities of various body sites. Abnormal expression of ALK protein, as seen in inflammatory myofibroblastic tumors, is absent. Increased numbers of IgG4-positive plasma cells in a subset of lesions raise the possibility that some cases may be related to the autoimmune phenomena of IgG4-associated disease.
Category: Genitourinary (including renal tumors)
Wednesday, March 6, 2013 9:30 AM
Poster Session V # 147, Wednesday Morning