Mycosis fungoides palmaris et plantaris successfully treated with radiotherapy: case report and mini-review of the published work

Mycosis fungoides palmaris et plantaris (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. We report a 73-year-old Japanese man who presented with an erosion on the left dorsal hand, a reddish tumor on the right palm, and hyperkeratotic erythematous plaques on the right sole. Skin biopsy showed histological features of mycosis fungoides (MF) with invasion into the deeper layers of skin. There was no visceral or lymph node invasion. We diagnosed this case as MFPP. External beam radiotherapy (EBRT) was performed to treat the hand lesions. Combination treatment with topical steroids and topical psoralen plus ultraviolet light therapy was performed to treat the right sole lesion, but was ineffective. Therefore, sequential EBRT was performed. Complete remission of all lesions was obtained. This is the first report of MFPP with a locally advanced tumor for which the efficacy of radiotherapy is described in detail. MFPP lesions occur on the dorsal aspect of hand or foot, and here we propose a classification of MFPP as hand and foot MF. The pathogenesis of MFPP is still unclear and further accumulation of data is required.