Carcinoid tumors of the eye and orbit: a clinicopathologic study of 15 cases, with histochemical and electron microscopic observations.

This clinicopathologic study includes 15 cases of carcinoid tumors of the eye and orbit. The patients ranged in age from 14 to 86 years (median, 53). No prediction for either gender was found. Seven tumors involved the orbit, seven the choroid, and one the iris. The primary site of origin of the carcinoid tumor was known in 12 cases: seven in the bronchus, one in the trachea, and four in the ileum. In three cases an orbital tumor was present but no other known primary neoplasm was clinically apparent. The postoperative follow-up period ranged from 0 to 4 years. The urinary levels of 5-hydroxyindoleacetic acid (5-HIAA) were elevated in four of ten patients tested, each of whom had a known primary tumor and two of whom had clinical evidence of the carcinoid syndrome. Four main histologic patterns were recognized: pattern A (solid lobules or masses), pattern B (trabecular or cord-like), pattern C (tubular or rosette-like) and pattern D (mixed). The apparently primary carcinoid tumors and the orbital or ocular metastases were closely related by their histologic patterns, histochemical staining characteristics, and ultrastructural features.