Prevalence of neoplasms in definite and probable mitochondrial disorders.

There are some indications that the prevalence of benign and malign neoplasms is increased in patients with a mitochondrial disorder (MID). This study aimed at calculating the prevalence of malign and benign neoplasms in MID patients compared to the general population. Among 103 adult patients with definite or probable MID 16 had a malignancy (15.5%) and 11 (10.7%) a benign neoplasm. Four patients had thyroid cancer, three patients had prostate cancer, two patients each colon cancer, or ovarian cancer, and one each lung cancer, basalioma, Paget carcinoma of the skin, Bowen disease, renal cancer, and urinary bladder cancer. One patient had two carcinomas. Five patients had lipomas, two thyroid adenoma, and one each meningeoma, ovarian adenoma, hemangioma of the liver, and pituitary adenoma. Compared to the general population, the prevalence of malignancies was 3-4 fold increased in definite and probable MIDs. Compared to a cohort of myotonic dystrophy type-1 patients, the prevalence was 1.4 fold increased. In conclusion, adult MID patients seem to carry an increased risk to develop malignancy or a benign neoplasm. Females with a MID seem to be predominantly at risk to develop a neoplasm.