ABSTRACT
A 41-year-old man presented with recurrent pustules and scales on both hands and feet for 1year and with neoplasm on the left toe for 4 months.On physical examination,there were multiple irregular rufous patches with lamellar white scales on bilateral thumbs,forefingers,thenar eminence,toes,and the onethird anterior part of bilateral soles.Deep-seated pustules and vesicles arising on some erythematous patches were disrupted with the formation of punctiform or patches of erosions covered by yellow brown crusts.Some toenails and fingernails were thickened and deformed.An obviously tender neoplasm measuring 4 cm × 3.5 cm× 3.5 cm was observed in the anterior part of the left fourth toe,which was a little indurated and obviously tender with superficial erosion,large amount of purulent exudates and fresh granulation tissue mixing to form black and thick blood crusts on the surface.Biopsy of the nail bed of the right index finger and neoplasm on the left toe revealed a diffuse,dense,and mixed infiltrate of small- to medium-sized atypical lymphocytes and a few inflammatory cells.Meanwhile,epidermotropism and Pautrier's microabscess were visible.Immunohistochemistry showed that the abnormal lymphocytes were positive for leukocyte common antigen (LCA),Vimentin,CD3,CD45RO,CD4,Bcl-2,partly positive for CD8,CD5,CD10,Ki-67 (＞ 80％ ),but negative for CD79a,CD20,CD30,cytokeratin,S-100,Bc1-6,anaplastic lymphoma kinase (ALK),HMBMS,CD1a or P63.Based on the above findings,a diagnosis of mycosis fungoides palmaris et plantaris was made.