OBJECTIVETo study the pathologic features, diagnosis, differential diagnosis and molecular characteristics of colloid carcinoma of the pancreas.

METHODSThe clinical findings, morphologic features, immunophenotype and K-ras gene alterations were investigated in 4 cases of pancreatic colloid carcinoma.

RESULTSIn the 4 cases of colloid carcinoma of the 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 mucin pools from the stroma. Three cases developed from pre-existing pancreatic ductal adenocarcinoma (IPMN), intestinal-type, and 1 from IPMN, pancreatobiliary-type. Immunohistochemical studies showed that MUC2 was positive in 3 cases, and MUC1 in 1 case. K-ras gene mutation was identified in 2 cases, showing a single-amino-acid substitution in codon 12, as Gly12Asp (GGT > GAT) and Gly12Arg (GGT > CGT).

CONCLUSIONSPancreatic colloid carcinoma is a rare variant of pancreatic ductal adenocarcinoma, which is associated with IPMN and mucinous cystic neoplasms. Positive MUC2 staining and absent MUC1 expression are commonly found, and K-ras gene mutation is occasionally identified in these tumors.

Adenocarcinoma, Mucinous ; genetics ; metabolism ; pathology ; surgery ; Adult ; Aged ; Carcinoma, Pancreatic Ductal ; pathology ; Diagnosis, Differential ; Exons ; Female ; Genes, ras ; Humans ; Male ; Middle Aged ; Mucin-1 ; metabolism ; Mucin-2 ; metabolism ; Mutation ; Pancreatic Neoplasms ; genetics ; metabolism ; pathology ; surgery

Clinicopathological characteristics and prognostic factors of mucinous carcinoma (MC) were compared with invasive ductal carcinoma-not otherwise specified (IDC-NOS). Clinicopathological characteristics and survivals of 104 MC patients were retrospectively reviewed and compared with those of 3,936 IDC-NOS. The median age at diagnosis was 45 yr in MC and 47 yr in IDC-NOS, respectively. The sensitivity of mammography and sonography for pure MC were 76.5% and 94.7%, respectively. MC showed favorable characteristics including less involvement of lymph node, lower stage, more expression of estrogen receptors, less HER-2 overexpression and differentiated grade, and better 10-yr disease-free survival (DFS) and overall survival (OS) (86.1% and 86.3%, respectively) than IDC-NOS (74.7% and 74.9%, respectively). Ten-year DFS of pure and mixed type was 90.2% and 68.8%, respectively. Nodal status and stage were statistically significant factors for survival. MC in Koreans showed similar features to Western populations except for a younger age of onset than in IDC-NOS. Since only pure MC showed better prognosis than IDC-NOS, it is important to differentiate mixed MC from pure MC. Middle-aged Korean women presenting breast symptoms should be examined carefully and evaluated with an appropriate diagnostic work-up because some patients present radiologically benign-like lesions.
Adenocarcinoma, Mucinous/diagnosis/genetics/*pathology ; Adult ; Aged ; Aged, 80 and over ; Breast/pathology ; Breast Neoplasms/classification/diagnosis/genetics/*pathology ; Carcinoma, Ductal/diagnosis/genetics/*pathology ; Disease-Free Survival ; Female ; Genes, erbB-2 ; Humans ; Korea ; Lymphatic Metastasis ; Mammography ; Middle Aged ; Prognosis ; Retrospective Studies ; Sensitivity and Specificity ; Survival Rate ; Young Adult