Abstract

Background: Cutaneous lymphoid hyperplasia (CLH) is a reactive lymphoid proliferation which may clinically and pathologically mimic lymphoma. It can be secondary to some infections, drugs, foreign agents, insect bites, and others.  Case Presentation: A 58-year-old male presented with longstanding pruritic rash on the back, abdomen, thighs, and arm which exacerbated during summer secondary to heat and sweat. He works with livestock and has many animals including cats, dogs, and horses with skin problems. Physical examination showed pink, scaly patches with annular borders, and papules. A punch biopsy of the papule in the arm showed superficial dermal nodular small lymphocytic infiltrates with occasional eosinophils. There was almost equal proportion of T and B cells by immunohistochemistry. B cell Gene rearrangement studies showed clonal immunoglobulin heavy chain (IgH). Tinea corporis was suspected clinically, and a re-biopsy from the arm and back was performed. The arm lesion again showed small lymphocytes and immunoblasts of T and B-cells. The biopsy from the back showed rare fungal hyphae. The microbiological cultures performed at this time showed Trichophyton species.  A retrospective review of the biopsies from the arm showed rare cross section of fungus. Conclusion: CLH can be seen secondary to Trichophyton infection. Repeated exposure to the pathogen from the livestock could be the cause of CLH. Though clinically suggestive of Tinea corporis, rare fungal hyphae were seen histologically, possibly secondary to the intense immune reaction. Clinical correlation, and awareness of CLH secondary to this common dermatophyte infection even with clonal gene rearrangement is important.