Ultrastructure of primary and metastatic ovarian carcinoids: analysis of 11 cases

The ultrastructure of 11 ovarian carcinoids was investigated. The 6 carcinoids with an insular pattern primary in the ovary or metastatic to it from the ileum displayed granules that were pleomorphic (dumbbell and reniform shaped) and varied from 90 to 410 mum, with an average diameter of 210 mum. Five trabecular carcinoids primary in the ovary or metastatic to if from the pancreas contained uniformly round granules with an average diameter of 185 mum and a range of 150-210 mum. These data confirm other reports that pleomorphic granules are typically associated with insular carcinoids of the midgut, and round granules with trabecular carcinoids of the foregut and hindgut.