胰腺胶样癌四例临床病理学分析

Colloid carcinoma of pancreas ： a clinicopathologic study of 4 cases

目的探讨胰腺胶样癌的临床病理学特征、诊断、鉴别诊断及分子生物学特点。方法分析4例胰腺胶样癌的临床特点，对标本进行病理形态学观察、免疫组织化学EnVision法和K—ras基因突变检测。结果4例胶样癌中3例发生在胰头部，患者均为男性；另1例在胰体尾部，为女性；平均发病年龄为56．5岁。其中2例首发症状为腹痛，1例为尿糖增高，1例为查体发现。3例大体形态为囊实性结节，囊内含黏液，1例大体呈实性。低倍镜下，纤维及胰腺组织中可见边界清楚的黏液结节，大的黏液湖巾可见纤细的纤维结缔组织间隔成多个小黏液湖；肿瘤细胞漂浮在黏液湖中，呈小巢或条索状，或腺管状，也可看到印戒细胞漂浮其中。3例癌周可见肠型胰腺导管内乳头状黏液性肿瘤（IPMN），仅例1伴发胰胆管型IPMN。免疫组织化学染色3例MUC2细胞膜阳性，1例MUC1阳性。3例中例1和例3发现K—ras基因突变，突变位点均佗于12密码子G1y12Asp（GGT〉GAT）和G1y12Arg（GGT〉CGT）。结论胰腺胶样癌是少见的胰腺导管腺癌亚型，经常伴发于1PMN和胰腺黏液性囊性肿瘤，应与普通胰腺导管腺癌、印成细胞癌及假性囊肿等病变相鉴别。免疫组织化学MUC2多阳性表达，MUCI多为阴性，K—ras基因突变率较低。

Objective To study the pathologic features, diagnosis, differential diagnosis and molecular charaeteristics of eolloid carcinoma of the pancreas. Methods The clinical findings, morphologic features, immunophenotype and K-ras gene alterations were investigated in 4 cases of pancreatic colloid earcinoma. Results In the 4 cases of colloid carcinoma of tile pancreas, three tumors were located in the head of the pancreas, one was located in the body and tail. The average age was 56. 5 years old. The presenting symptom was abdominal pain in 2 cases, increased level of U-GLU in 1 patient, and an accidental finding presented in 1 patient. Grossly, 3 cases were cystic and solid, with mucin in the cyst; 1 case was solid. Microscopically, the colloid carcinoma was characterized by large pools of extracellular mucin, containing neoplastic cells, which were in the pattern of cuboidal, cribriform or irregular clusters, or formed an incomplete lining separating muein pools from the stroma. Three cases developed fi＇om pre-existing pancreatic ducta] adenocarcinoma （IPMN）, intestinal-type, and 1 fi＇om IPMN, pancreatobiliary-type. hnmunohistochemical studies showed that MUC2 was positive in 3 cases, and MUC1 in 1 ease. K-ras gene mutation was identified in 2 cases, showing a single-amino-acid substitution in codon 12, as Glyl2Asp （ GGT 〉 G_AT） and Glyl2Arg（ _GGT 〉 C_GT）. Conclusions Pancreatic colloid carcinoma is a rare variant of pancreatic ductal adenocarcinoma, which is associated with IPMN and mucinous cystic, neoplasms. Positive MUC2 staining and absent MUCI expression are commonly found, and K-ras gene mutation is occasionally identified in these tumors.