Report of two cases of quintuple primary malignancies and review of the literature.

Multiple primary malignant neoplasms (MPMN) are not uncommon, however, finding more than three primary malignancies in one individual is unusual. Surviving five malignancies is considered exceptional. Two patients surviving five primary malignant neoplasms for 12 and 18 years are reported: a 55-year-old woman with a squamous cell carcinoma of the larynx, two carcinomas of the breast, a carcinoma of the kidney and an adenocarcinoma of the colon, and a 75-year-old woman with a sarcoma of the myometrium, a carcinoma of the thyroid, an adenocarcinoma of the rectum, a leiomyosarcoma of the colon and a bronchial carcinoid. Only twelve other reported cases with five or more primary infiltrating malignancies involving more than three sites, diagnosed while the patient was alive have been found. Relevant features were that colon cancer was quite often present more than once and survival was longer than expected for the stage (median overall survival, 20 years; 95% confidence interval: 12-28 years).