Abstract

A 72-year-old man presented with scattered grouped yellow-orange papules over the abdomen and back. A similar, isolated lesion was biopsied seven months prior with similar findings. Histopathology showed compact parakeratosis overlying an attenuated epidermis with spongiosis and lymphocyte epidermotropism. The intraepidermal lymphocytes were small but showed nuclear atypia; the dermis contained a dense infiltrate of larger pleomorphic cells with occasionally indented nuclei and frequent mitotic activity. The lymphocytes expressed CD3, CD8, CD30, and TR[OSM1]  beta F1 by immunohistochemistry. CD30 showed a characteristic pattern with dark, intense dermal staining and lighter epidermal staining. The cells did not express TR delta, CD4, CD56, ALK (D5F3), TIA1, granzyme B, or perforin. CD20 highlighted occasional B-cell aggregates. A clonal TR rearrangement was detected by PCR (BIOMED2). FISH revealed a DUSP22 – IRF4 rearrangement. Peripheral blood flow cytometry and comprehensive imaging[MJ2]  showed no evidence of a systemic process. The combined clinical and pathologic features were most consistent with lymphomatoid papulosis with DUSP22/6p25.3 rearrangement. Lymphomatoid papulosis with DUSP22 rearrangement is a rare, clinically indolent entity with fewer than twenty cases reported in the literature. Morphologic features can mimic primary cutaneous anaplastic large cell lymphoma, and transformed mycosis fungoides. DUSP22 rearrangements can be seen in several types of T-cell lymphomas, including cutaneous ALK-negative anaplastic large cell lymphoma, which may have clinical and pathologic overlap with lymphomatoid papulosis. As with all lymphomatoid papulosis patients, close clinical follow up will be required to be sure this patient does not have, and does not develop, a more aggressive lymphoproliferative disorder.