CASE PRESENTATION
A 76-year-old man with no significant past medical history presented to our clinic with a six months skin hyperpigmentation and fatigue. The patient was treated with skin-lightening and antisolar creams but with no improvement. Clinical examination showed brown to violet hyperpigmented patches on face and upper trunk. Mucosal examination showed -violaceous plaques on the upper palate in addition to yellow sclera with red to purple patches on the inner aspect of both lower eyelids (figure 1). Physical examination showed lymphadenopathy especially in axillary area. Laboratory evaluations revealed white blood cell 4.6 × 10 3 /L with neutrophil and lymphocyte differentiation (18% and 50%, respectively), hemoglobin 10.5 g/dl and platelet count of 72 × 10 3 μl.
Two skin biopsies from face and chest were taken with differential diagnoses of angiosracoma, lymphoma, and lichen planus. The result showed dense dermal multinodular perivascular and periadnexal infiltration with atypical mononucleated cells with IHC evidence consistent with leukemic dermal infiltration (figure 2). Immunohistochemistry (IHC) staining was carried out according to morphological findings and showed infiltrated cells with irregular indented nuclei and high nuclear/cytoplasmic ratio which was positive for leukocyte common antigen (LCA). No CD20, CD79a, CD3, CD45, CD30, MPO or CD68 were detected in infiltrated cells. Clinical and histopathological findings in addition to the flow cytometric immunophenotyping of peripheral blood were compatible with myeloid leukemia m5.