Lymphocytoma Cutis - A Case Report

Without tissue biopsy and holistic review of presentation, histology, and immunohistochemistry, lymphocytoma cutis (LC) can often be misdiagnosed as other benign conditions or malignant pathologies such as cutaneous B cell lymphoma (CBCL). A 36-year-old female presented with a two-year history of a progressive indurated, edematous plaque in the preauricular area. At presentation, the patient also had labs significant for thrombocytopenia and eosinophilia. Original treatment with topical steroids did not lead to clinical improvement of the lesions. Punch biopsy revealed reactive lymphoid hyperplasia with polyclonal lymphoid infiltrates of small lymphocytes, histiocytes, eosinophils, and plasma cells. Diagnosis of LC was made and our patient was treated with serial 5 mg intralesional triamcinolone injections. Clinical improvement was seen beginning at 2 months. Diagnosing LC can be particularly difficult as the clinical presentation is ubiquitous and can resemble several other conditions such as CBCL, cutaneous lupus erythematosus, sarcoid, or hypersensitivity reactions. Recognition of the typical histologic findings of top-heavy dermal mixed-cellular infiltrates along with polyclonal kappa and lambda hybridization on immunohistochemistry is often essential in arriving at the correct diagnosis. Following diagnosis of LC, long-term surveillance is recommended as malignant transformation is a possibility.