Insulin-mediated pseudoacromegaly: a case report and review of the literature.

A 23 year old female patient presented with oligoamenorrhea. She had excessive weight gain and had noticed hirsutism, enlargement of the jaw, increase in her ring and shoe size, increased sweating and darkening of her skin in flexural areas. Examination revealed a large framed woman with coarse facial features, large hands and feet, prognathism, acanthosis nigricans, hirsutism, acne and many skin tags. GH and IGF-1 were normal. MRI of pituitary showed a 7mm microadenoma, believed to be non-secretory with normal pituitary hormonal workup. She had marked elevation of serum insulin, elevated testosterone and mixed hyperlipidemia. The occurrence of acromegaloid manifestations is an unusual phenomenon seen in a subset of patients with insulin resistance. In vitro studies in fibroblasts obtained from such patients have revealed impairment of metabolic, but preservation of mitogenic insulin signaling. Insulin-mediated pseudoacromegaly is an unusual syndrome that combines severe insulin resistance and an acromegaloid phenotype. Physicians should consider this possibility while evaluating patients with similar clinical and laboratory features.