Acquired lipodystrophy following use of pembrolizumab

This case report details a 65-year-old female with Hashimoto's hypothyroidism and stage III melanoma who developed acquired generalized lipodystrophy (AGL), a rare immune-mediated adverse event, following pembrolizumab treatment. The patient was initially treated with nivolumab but was switched to pembrolizumab after developing optic neuritis. After starting pembrolizumab, the patient experienced significant weight loss and lipoatrophy in the face, thighs, and buttocks, alongside hypertrophy of the fat pads in her axillae, supraclavicular, and suprapubic areas. The patient also exhibited symptoms of marked insulin resistance and hypertriglyceridemia, indicative of AGL. Pembrolizumab treatment was discontinued after the patient developed additional side effects including hepatitis, hypophysitis, and thyroiditis, and the patient was commenced on steroid therapy. The patients insulin resistance and hypertriglyceridemia subsequently improved. Genetic sequencing excluded a genetic cause for her lipodystrophy. This is the fourth case of a patient developing AGL following administration of pembrolizumab, and the third for advanced melanoma. Since pembrolizumab administration for treatment of advanced melanoma is becoming more common, it necessitates clinician awareness to potential, rare complications not commonly defined in initial clinical trials.