Mitochondrial diabetes accompanied by benign symmetric lipomatosis - A case report

A nonalcoholic woman in her 60s being treated for diabetes was admitted to the hospital due to the progressive increase of a subcutaneous tumor around her neck over 2 years. The largest part was 20 cm in length, and was seen on the posterior neck and back. She also had severe hearing loss and dilated cardiomyopathy. Laboratory data revealed elevated levels of lactate and pyruvate, while magnetic resonance imaging of the neck revealed prominent fat accumulation, and the pathologic findings showed a lipoma. From these findings and the tumor's characteristic appearance, the diagnosis was confirmed as benign symmetric lipomatosis (Madelung's disease). Furthermore, the patient was diagnosed as having mitochondrial diabetes associated with G→A substitution at nucleotide 8363 in the mtDNA. Benign symmetric lipomatosis associated with mitochondrial diabetes is extremely rare.