Increased prevalence of malignancy in adult mitochondrial disorders

OBJECTIVES there are indications that patients with a mitochondrial disorder (MID) develop malignomas or benign tumors more frequently than the general population. The aims of the study were to find out if the prevalence of tumors is actually increased in MID-patients and which of the malignomas or benign tumors are the most frequent. METHODS The charts of MID-patients were retrospectively evaluated for the presence of malign or benign tumors. MID was diagnosed according to the modified Walker-criteria. RESULTS Among the 475 MID-patients screened for tumors, at least a single malignoma was found in 65 patients (13.7%), and at least a single benign tumor in 35 patients (7.4%). Among those with malignancy, 22 were men and 43 women. Among those with a malignancy, 1 had definite MID, 9 probable MID, and 55 possible MID. The most common of the malignancies was breast cancer, followed by dermatological, gynecological, and gastrointestinal malignancies. The most frequent of the benign tumors was lipoma, followed by pituitary adenoma, meningeomas, carcinoids, and suprarenal adenomas. Compared to the general population, the prevalence of malignancies and of benign tumors was markedly increased. The female preponderance was explained by the frequent maternal inheritance of MIDs. CONCLUSIONS Adult patients with a MID, particularly females, carry an increased risk to develop a malignancy or a benign tumor. Since malignancy is an important determinant for their outcome, these patients should be more accurately screened for neoplasms, not to overlook the point, at which an effective treatment can no longer be provided.