Skin Changes Due to Massive Weight Loss: Histological Changes and the Causes of the Limited Results of Contouring Surgeries.

Purpose: Outcomes of body contouring surgeries in patients who previously had obesity are limited because of the loss of skin quality. This study aimed to evaluate the morphometric characteristics of collagen and elastic fibers of the skin in the abdominal epigastric region of patients who had massive weight loss following bariatric surgery and compared such with the skin characteristics of patients with morbid obesity.

Methods: This observational study compared skin fragments from the epigastric region of 20 patients who had massive weight loss due to bariatric surgery and 20 patients with morbid obesity. The morphometric analysis was performed on the collagen system using the Picrosirius/polarized light method and on the elastic system using the Weigert's resorcin-fuchsin method.

Results: Reduction of thick collagen fibers (p = 0.048), increased thin collagen fibers (p = 0.0085), and increased elastic fiber density (p < 0.001) were observed in the massive weight loss group. No differences were found between the groups regarding mean age (p = 0.917) and total amount of collagen fibers (p = 0.3619). Structural dermis alterations in the massive weight loss group demonstrated collagenous remodeling, with consequent reduction of thick, organized, structured, and directed fibers in favor of thin, misaligned, and loosely arranged fibers. Weight loss was also associated with increased skin elasticity.

Conclusion: The morphometric changes in the collagen and elastic system scientifically explained the already established clinical perception of cutaneous alterations in patients who had massive weight loss following bariatric surgeries.