Background: Anatomical studies show that facial fat is partitioned into distinct compartments, with the nasolabial fat pad in a superficial compartment and the deep medial cheek fat in a deep compartment. Gross morphologic differences may exist between these fat depots, but this has never been established at the cellular level.
Methods: Adipose tissue specimens from nasolabial fat and deep medial cheek fat pads were obtained from 63 cadaveric specimens (38 female and 25 male cadavers) aged 47 to 101 years (mean, 71 years). Thirty-seven cadavers had a normal body mass index (≤25 kg/m) and 26 cadavers had a high body mass index (>25 kg/m). Cross-sectional areas of individual adipocytes were calculated digitally and averaged from histologic sections of the adipose tissue samples.
Results: The average adipocyte size of nasolabial fat is significantly (p < 0.0001) larger than that of deep medial cheek fat. The average adipocyte size in both nasolabial and deep medial cheek fat is significantly (p < 0.0001) larger in subjects with high compared with low body mass index. Although the overall average adipocyte size is significantly (p < 0.0001) larger in female than in male subjects, this sexual dimorphism is lost in the nasolabial fat depots of overweight subjects and in the deep medial cheek depots of normal-weight subjects.
Conclusions: The significantly smaller adipocyte size in deep medial cheek fat relative to nasolabial fat in elderly subjects supports the theory that deep and superficial facial fat pads are morphologically different. Future investigation of the metabolic and structural properties of these fat compartments will help us understand the different patterns of volumetric facial aging.