Atypical Lymphocytic Lobular Panniculitis / 대한피부과학회지

ABSTRACT

Atypical lymphocytic lobular panniculitis (ALLP) is a recently described entity characterized by self-limiting plaques that manifest a waxing and waning course. Although ALLP is known as a benign condition, it needs adequate follow-up to determine the risk of progression to subcutaneous panniculitis-like T-cell lymphoma (SPTCL) because ALLP has morphologic and biologic similarities with SPTCL. We report a case of ALLP in a 13-year-old girl who presented with an unusual tumor-like erythematous mass on the left thigh but without systemic symptoms or laboratory abnormalities. The histopathologic findings showed a dense and diffuse infiltration of the fat lobules by small-to-medium-sized atypical lymphocytes including focal atypical mitosis. Some cells showed characteristic peripheral rimming of individual adipocytes. However, prominent lymphoid atypia, fat necrosis, vasculitis, vascular thrombosis, erythrophagocytosis, mucin deposition, and the striking dominance of CD8+ lymphocytes seen in SPTCL were not detected. The lesion resolved spontaneously in 6 months and there was no recurrence over a 24-month follow-up period.