摘要目的 探讨皮肤恶性混合瘤( malignant mixed tumor,MMT)的临床病理学特征、诊断与鉴别诊断及治疗方法.方法 对2018年1月青海大学附属医院确诊的皮肤MMT伴小汗腺汗孔癌(eccrine porocarcinoma,EP)病例的临床病理学特征及免疫组织化学表达进行观察并文献复习.结果患者男性,64岁.双手多发皮疹4年,3处病变切除送病理检查.病变大小0.5～2.2 cm.左小指和右小指病变为皮肤MMT伴EP.右手环指病变为典型的EP 组织学形态.皮肤MMT由上皮和间质两种成分构成,浸润性生长,血管壁侵犯.腺上皮形成单层或双层腺管,伴中-重度细胞不典型性、多形性和核分裂象增加,不伴肌上皮的腺管呈汗管癌结构.肌上皮形成黏液、软骨样基质,软骨细胞伴中度不典型性. EP由可见胞质内空腔和管样及鳞状分化的基底样细胞构成,且异型性明显.免疫组织化学示MMT腺管结构的腔面上皮细胞角蛋白(CK)7、上皮细胞膜抗原(EMA)和CD117阳性,肌上皮S-100蛋白、CK5/6和p63表达,基质细胞S-100蛋白表达.需与化生性癌、恶性肌上皮瘤和不典型皮肤混合瘤等鉴别. MMT局部复发、转移率高.保障切缘阴性的外科切除是最主要的治疗方式,辅助性放、化疗效果有限.结论 皮肤MMT伴EP 罕见.诊断依靠病理形态学特征,免疫组织化学有助于鉴别诊断.临床经过不可预知,充分外科切除后需长期随访.

abstractsObjectiveTo investigate the clinicopathologic features, immunophenotype, pathological diagnosis and treatment of malignant mixed tumor (MMT). Methods Clinical and pathological features including immunohistochemical phenotypes were analyzed in a case of MMT accompanied with eccrine porocarcinoma (EP) involving both hands, diagnosed definitely in January 2018 along with review of relevant literature. Results A 64-year-old man presented with multiple rash on both hands for 4 years. Three lesions of 0.5 to 2.2 cm were removed for pathological evaluation. The pathological changes on little finger of left and right hands were MMT with EP,whereas that removed from the right ring finger was EP. MMT showed infiltrative growth with vascular wall invasion and consisted of epithelial ( glandular or tube differentiation) and mesenchymal components ( mucinous and/or cartilage stroma). The endothelial cells showed moderate to severe cytological atypia, nuclear pleomorphism and increased mitotic activity. The glandular component had histological characteristics of syringocarcinoma with moderately atypical chondrocytes but without myoepithelium. EP was composed of basal cells with visible vacuoles in cytoplasm and the presence of tubular and squamous differentiation, along with obvious atypia. Immunohistochemically cavosurface epithelium of glandular differentiation of MMT showed positivity for CK7, EMA and CD117. Myoepithelium showed S-100, CK5/6 and p63 positivity and stromal cells were positive for S-100. Differential diagnoses included metaplastic carcinoma, malignant myoepithelioma and atypical mixed tumor of skin. Conclusions MMT with EP is extremely rare.The diagnosis of MMT depends on the morphologic features. Immunohistochemical staining is helpful for differential diagnosis. Surgical excision with safety margins is the treatment of choice. Complementary radiotherapy and/or chemotherapy is still controversial. The clinical course of MMT is deemed unpredictable and long-term follow-up is necessary.