Abstract

78-year-old African American female with no significant past medical history, presented with a scaly rash involving both hands since, 8 months. Physical examination showed erythematous, hyperkeratotic, hyperpigmented plaques on bilateral hypothenar eminence, palmar and dorsal fingers. Punch biopsy showed psoriasiform acanthosis with spongiosis, hyperkeratosis, and superficial perivascular lymphoid infiltrate. Epidermotropism characterized by presence of solitary units and clusters of enlarged, hyperchromatic lymphocytes tagging along the dermoepidermal junction and forming intraepidermal clusters was seen. There was no evidence of syringotropism. Immunohistochemical work-up showed epidermal and dermal lymphocytes to be CD3+ with diminished expression of CD7, and CD4:CD8 ratio of greater than 10:1. T-cell receptor beta gene rearrangement was positive. There was no systemic involvement and peripheral blood flow cytometry was normal. The diagnosis was consistent with mycosis fungoides palmaris et plantaris (MFPP). MFPP is a rare variant of cutaneous T-cell lymphoma, limited to the palms and soles that is not widely recognized because of its uncommon occurrence. Sezary syndrome which presents with palmoplantar involvement should be excluded clinically. Of note, palmoplantar disease is more frequently seen in syringotropic variant of mycosis fungoides. Our case was certainly peculiar as it did not show evidence of eccrine gland or duct involvement. It is important for both clinicians and pathologists to be aware of this rare variant of mycosis fungoides, which is a clinical and histologic mimicker of eczematous (contact and dyshidrotic) dermatitis and psoriasis. Presence of disproportionate epidermotropism, lymphocytic atypia and syringotropic involvement can be clues for recognition of this disease entity.

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