Granuloma annulare with prominent lymphoid infiltrates ("pseudolymphomatous" granuloma annulare).
Granuloma annulare (GA) is characterized histopathologically by 3 patterns: necrobiotic granuloma, interstitial incomplete form and, rarely, sarcoidal or tuberculoid granuloma. The amount of lymphoid infiltrate in GA is usually limited. We describe 10 cases of GA with prominent "pseudolymphomatous" lymphoid infiltrates mimicking cutaneous lymphoid hyperplasia. Patients were 6 males and 4 females (mean age 49.9 years, median age 47 years, age range 25-70). Lesions were localized to a limited area of the body (n = 6), or involved the entire trunk (n = 3), or were generalized (n = 1). The correct clinical diagnosis of GA was provided only in 30% of the cases. In all cases, histopathologic features were characterized by dense, nodular, superficial, and deep infiltrates of lymphocytes. Immunohistology revealed predominance of T lymphocytes in 7 of 7 tested cases. This "pseudolymphomatous" variant of GA represents a pitfall in the histopathologic diagnosis of the disease and may be misinterpreted as other types of cutaneous lymphoproliferative disorders.
Department of Dermatology, Research Unit of Dermatopathology, Medical University of Graz, Austria.
Carlo
C
Cota
Gerardo
G
Ferrara
Lorenzo
L
Cerroni
D000328:Adult; D000368:Aged; D001706:Biopsy; D020405:Dermis / Q000276:immunology / Q000473:pathology; D005260:Female; D016460:Granuloma Annulare / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D008221:Lymphoid Tissue / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D019310:Pseudolymphoma / Q000150:complications / Q000175:diagnosis* / Q000276:immunology; D013601:T-Lymphocytes / Q000473:pathology*