For the purpose of investigating the pattern of E-cadherin (E-CD) expression in thymomas, 72 cases were immunostained using monoclonal antibody (HECD-1) and microwave-enhanced immunohistochemical method on formalin-fixed, paraffin-embedded tissue sections. The thymomas were classified according to modified Muller-Hermelink classification. The spindle-shaped, medullary type tumor epithelial cells in medullary (3 cases) and composite type (20 cases) thymomas rarely expressed E-CD except in focal areas showing microcystic change observed in 8 cases. Meanwhile, the cohesive epithelioid tumor cells in every case of well-differentiated thymic carcinomas (WDTC) (29 cases) expressed E-CD. The epithelial cells in cortical type (13 cases) expressed stronger E-CD compared with those of organoid type (7 cases). In cases of WDTC admixed with cortical type, we observed increasing expression of E-CD as the tumor epithelium forms cohesive sheets. We could not find any loss of E-CD expression in invasive foci of the 11 cases of high-staged WDTC examined. Since the results of our study show a strong correlation between E-CD expression and epithelioid morphology of the tumor, E-CD seems to play a major role as a morpho-regulatory factor rather than as a suppressor of invasion in organotypic thymomas.
Adolescence ; Adult ; Aged ; Cadherins/immunology ; Cadherins/analysis* ; Female ; Human ; Immunohistochemistry ; Male ; Middle Age ; Neoplasm Staging ; Thymoma/pathology ; Thymoma/classification ; Thymoma/chemistry* ; Thymus Neoplasms/pathology ; Thymus Neoplasms/classification ; Thymus Neoplasms/chemistry*

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant tumor syndrome. Thymic carcinoid tumors in MEN1 are not common and their natural history is little known. But development of thymic carcinoid tumors is important because in 1993, they were identified as a frequent case of death. There has not been a report of case in Korea so far. We encountered a case of thymic carcinoid in MEN1. A 42 year old man was referred presenting with diabetes of 12 years duration. Abnormal findings in his blood chemistry were hypercalcemia and hyperprolactinemia. 99mTc- sestamibi scintigraphy showed parathyroid adenoma and hyperplasia. Sella MRI showed pituitary macroadenoma. Abnormal CT scan demonstrated multiple pancreas islet cell tumors, bilateral adrenal tumor and thymoma. Subtotal parathyroidectomy with thymectomy was perfomed and thymic carcinoid was confirmed. This is the first report of thymic carcinoid with MEN1 in Korea.
Adenoma, Islet Cell ; Adult ; Carcinoid Tumor* ; Chemistry ; Humans ; Hypercalcemia ; Hyperplasia ; Hyperprolactinemia ; Korea ; Magnetic Resonance Imaging ; Multiple Endocrine Neoplasia Type 1* ; Multiple Endocrine Neoplasia* ; Natural History ; Pancreas ; Parathyroid Neoplasms ; Parathyroidectomy ; Radionuclide Imaging ; Thymectomy ; Thymoma ; Tomography, X-Ray Computed