Carcinoid syndrome with unknown primary: a case report

Carcinoid syndrome usually is associated with a classic presentation, the diagnosis of which is supported by elevations in neuroendocrine substances such as 5-hydroxyindoleacetic acid and by localization and pathologic identification of a neuroendocrine tumor. The authors report a patient for whom there was a 7-year delay in diagnosis and even then a primary tumor could not be localized.