Lymphomatoid Papulosis Presenting With B‐Cell Lymphoma: A New Association?

Lymphomatoid papulosis (LyP) is a cutaneous T‐cell lymphoproliferative disorder, characterised by recurrent crops of necrotic self‐healing papules and nodules. Although chronic, LyP typically has a benign clinical course in the majority of cases. Histologically, a malignant appearing T‐cell lymphoid infiltrate is seen. The atypical cells often resemble the cerebriform cells of mycosis fungoides or Reed‐Sternberg cells in Hodgkin lymphoma. Approximately 10–20% of the patients go on to develop lymphomas, including mycosis fungoides, CD30‐positive anaplastic large cell and Hodgkin lymphoma. We report a case of LyP associated with a B‐cell lymphoma. A 50‐year‐old male, presented with scattered erythematous scaly papules, some with central crust, located on the arms, trunk and leg of one‐month duration. A skin biopsy revealed a polymorphous infiltrate with many large atypical lymphocytes, resembling Reed Sternberg cells. By immunohistochemistry, the large cells were positive for T‐cell markers and CD30. Subsequently, he developed fever, night sweats and diffuse lymphadenopathy. A lymph node biopsy showed a vaguely nodular proliferation of small to medium lymphocytes. Immunophenotypic and flow cytometric studies best characterised the process as mantle cell lymphoma. Although, LyP has been previously associated with lymphomas of above‐mentioned types, this is an extremely unusual case presenting with a low‐grade B‐cell lymphoma.