以皮肤单核细胞肉瘤为首发表现的急性单核细胞白血病的特征研究

Characteristic analysis of monoblastic sarcoma cutis preceding acute monoblastic leukemia

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。

A 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, lymphadeneetasis, 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 ceils had nuclear groove and nucleoli. Immunohistoehemical 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 monoblastie sarcoma cutis preceding acute monoblastic leukemia was made.