Bolus lipofilling: morphological characteristics and clinical application

Objective. To conduct a morphological study and clinical justification of new properties of fat after bolus injection. Material and methods. Pathomorphological study of fat boluses was carried out in two groups of patients. In the first group (5 patients), histological examination of soft tissue specimens followed removal of fat accumulations after injection of large volumes of autologous fat (bolus injection). The second group included 5 patients who underwent prepectoral breast reconstruction with bolus fat injection 3 years ago. All specimens were prepared according to standard method and staining with hematoxylin and eosin. Histological structure was examined at 100-fold magnification. A total of 40 specimens were studied. Results. In large lipoboles, we observed adipo-fibrous capsule as a multiple-layer tissue with vascular inclusions, neutrophil and lymphocytic-macrophage infiltration and cell detritus. Small boluses were dense elastic masses with internal accumulations of fibrous tissue, inclusions of adipose tissue and small number of oily cysts without tissue detritus. After 3 years, structure of fat boluses changed. Thus, fibrous trabeculae with blood vessels departed inward from the capsule, and groups of adipocytes and preadipocytes were concentrated around these trabeculae. Conclusion. Large and small fat boluses represent a new safe approach in lipofilling as a volume and shape-forming element in breast reconstruction. Small fat boles undergo fibrosis with fatty inclusions and can be used in facial contouring.