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Case Reports

Abstract

Lymphoplasmacytic plaque in children is an emerging benign chronic dermatosis that affects children with a female predominance. Herein, we describe a case of lymphoplasmacytic plaque in a healthy 9-year-old girl. She presented with a solitary well-demarcated 4.0 x 1.0 cm red-purple plaque on the left radial dorsal wrist present for several months. Systemic symptoms and additional skin lesions were absent. The patient was then referred to our institution for surgical excision.  

Histologically, the excisional specimen showed pseudoepitheliomatous epidermal hyperplasia with focal parakeratosis overlying a dense and thick lymphoplasmacytic band-like infiltrate with perivascular and periadnexal distribution. Focal lichenoid-interface changes and scattered histiocytes coalescing in clusters with focal multinucleated forms were seen. PASD and AFB histochemical stains, and a spirochete immunohistochemical stain were negative for organisms. Via immunohistochemistry, the lymphoid infiltrate consisted of a mixture of B- and T-cells with an approximate 1:1 ratio. The T-cells showed a CD4:CD8 ratio of 1:1. The plasma cells were positive for CD138 and polytypic on Kappa and Lambda in-situ hybridization. 1-month follow-up showed no recurrence.  

Lymphoplasmacytic plaque in children is a rare entity that can be mistaken for infections, inflammatory processes, and lymphoproliferative or pseudolymphomatous disorders. Although it was originally described as a persistent solitary plaque involving the pretibial area, it can also affect other sites. Histologically, this entity is characterized by a dense pandermal lymphoplasmacytic infiltrate with focal histiocytes and enlarged vessels. Treatment modalities including topical and/or intralesional steroids, pulse-dye lasers, observation, and excision have been reported in literature.