Increased tissue leptin hormone level and mast cell count in skin tags: a possible role of adipoimmune in the growth of benign skin growths.

Background: Skin tags (ST) are common tumors. They mainly consist of loose fibrous tissue and occur on the neck and major flexures as small, soft, pedunculated protrusions. Decrease in endocrine, hormone level and other factors are thought to play a role in the evolution of ST. Leptin is an adipocyte-derived hormone that acts as a major regulatory hormone for food intake and energy homeostasis. Leptin deficiency or resistance can result in profound obesity and diabetes in humans. A role of mast cell in the pathogenesis of ST is well recognized.

Aims: To investigate the role of leptin in the pathogenesis of ST and to clarify whether there is a correlation between mast cell count and leptin level in ST.

Methods: Forty-five skin biopsies were taken from 15 patients with ST. From each patient, a biopsy of a large ST (length >4 mm), a small ST (length <2 mm) and a normal skin biopsy (as a control) were taken. The samples were processed for leptin level. Skin biopsies were stained with hematoxylin and eosin and toluidine blue-uranyl nitrate metachromatic method for mast cell count was used.

Results: There was a significant increased level of leptin in the ST compared to the normal skin. It was highly significant in small ST than in big ST (P = 0.0001) and it was highly significant in small and big ST compared to controls, P = 0.0001 and P = 0.001, respectively. There was a significant increase in mast cell count in the ST, which did not correlate with the increased levels of leptin.

Conclusion: This is the first report to demonstrate that tissue leptin may play a role in the pathogenesis of ST. The significant increase in the levels of leptin and mast cell count in ST may indicate a possible role of adipoimmune in the benign skin growths.