摘要患儿4个月始发病,以额头、四肢皮肤出现多发皮色结节为特征,一般情况好,未触及肝、脾、淋巴结肿大、睾丸无明显异常、牙龈无异常增生.皮损组织病理:表皮大致正常,真皮及皮下弥漫浸润的异形细胞,体积中等偏大,胞质少,核椭圆形,不规则形,染色质细,个别细胞可见核沟及核仁.免疫组化:S-100蛋白阳性,CD68阳性；CD1阴性,Ki-67阳性率40％；CD21阴性,CD4部分细胞弱阳性.髓过氧化物酶( MPO)阴性,CD56阳性,CD123阳性,CD163阳性.骨髓片见原、幼单核细胞占0.245.诊断:以皮肤单核细胞肉瘤为首发的急性单核细胞白血病.

abstractsA 1-year-old boy developed multiple skin-colored nodules on the forehead and extremities when he was 4 months old.Physical examination revealed that his general condition was well with no hepatomegaly,splenomegaly,lymphadenectasis,testicle abnormality or gingival hypertrophy.Pathologically,the epidermis was normal,while the dermis and subcutaneous tissue were diffusely infiltrated with medium-to large-sized deformed cells,which had a small amount of cytoplasm,oval nucleus,irregular shape and fine chromatin.Some infiltrating cells had nuclear groove and nucleoli.Immunohistochemical studies showed that the tumor cells were positive for S-100 protein,CD56,CD123,CD163,CD68,Ki-67 (40％),weakly positive for CD4 (some),but negative for myeloperoxidase,CD1,CD21.Bone marrow smears showed a 24.5％ infltration by monoblasts and promonocytes.A diagnosis of monoblastic sarcoma cutis preceding acute monoblastic leukemia was made.