The intriguing nature of gastric tumors in Carney's triad. Ultrastructural and immunohistochemical observations.

The authors describe clinical and pathologic features present in an adolescent girl who had a gastric tumor and mediastinal mass. The latter was shown to be a paraganglioma, and the gastric neoplasm was classified as malignant "leiomyoblastoma," with the use of current histologic criteria. This tumor had metastasized to the liver but not to the lungs. Although the histologic criteria for leiomyoblastoma were fulfilled, no definite evidence of smooth-muscle cell differentiation was present ultrastructurally or by immunostaining methods. Gastric tumors that form part of "Carney's triad" are known to differ clinically and pathologically in important ways from smooth-muscle cell malignant neoplasms that are not part of this syndrome. Some have been classified as gastrointestinal autonomic nerve tumors, but the current study did not confirm this contention. The nature of gastric leiomyoblastomas in Carney's multitumoral association remains undecided.