Hematopoietic stem cell transplantation-associated partial lipodystrophy

Hematopoietic stem cell transplantation (HSCT)-associated partial lipodystrophy (HSCT-PL) is a serious metabolic complication that develops in remote period among childhood cancer survivors treated with HSCT with total body irradiation (TBI). Since the first proposal in 2013, HSCT-PL seems to be increasingly recognized as a distinct disease entity. The patients with HSCT-PL show profound metabolic dysfunction including insulin resistance, diabetes, elevated triglycerides, and hepatic steatosis. Their body mass index is low-normal, although they show visceral fat accumulation and increased waist-to-hip ratio. In addition, HSCT-PL is characterized by Dunnigan phenotype: lipoatrophy in buttock and extremities combined with lipohypertrophy in face and neck. Although the precise pathogenesis is still obscure, radiation-induced damage to adipose progenitor cells, leading to accelerated senescence, seems to be a main pathway. Literature survey identified 17 patients of HSCT-PL with sufficient information from 12 reports. Among them, clear female predominance (15 females) and possible ethnic difference in disease prevalence (11 Japanese) were ascertained. Genetic factors may be involved in those epidemiological traits. There remains much to be clarified, including establishment of reliable diagnostic procedure, elucidation of long-term prognosis, and invention of effective treatment. Metreleptin is one of the promising options, and the accumulation of its therapeutic efficacy are warranted.