Probable Rabson-Mendenhall syndrome presenting with acanthosis nigricans: a case report

Abstract

Rabson-Mendenhall syndrome (RMS) is a rare autosomal recessive disorder caused by mutations in the insulin receptor gene (INSR), resulting in severe insulin resistance. We report the case of an 8-year-old boy who presented with progressive acanthosis nigricans of the neck, coarse facial features, generalized hypertrichosis, dental abnormalities, a fissured tongue, thickened nails, penile hypertrophy, and hepatomegaly. Laboratory results indicated hyperinsulinemia, severe insulin resistance and fasting hypoglycemia. Based on the clinical and laboratory findings, Rabson–Mendenhall syndrome was considered. Genetic confirmation was not performed because it was unavailable in our country. This case highlights the importance of recognizing acanthosis nigricans as a clinical marker of inherited metabolic syndromes, and the important role of dermatologists in its early recognition.