Studies on subcutaneous fat necrosis of the newborn

Abstract

Biopsy specimens from the skin and subcutaneous fat tissue of four cases with neonatal subcutaneous fat necrosis were made and investigated by light and electron microscopy at 2, 4, and 6 weeks, and 5 months (Case 2) from the onset of the disease. Three stages of ultrastructural change of fat cells were observed. The evolution of crystal formation in the fat cells was seen and phagocytosis of crystals and fat droplets by macrophages and foreign-body giant cells was also noted. In the light microscope accumulation of calcium concretions in the spaces between and inside the fat cells was found. In the electron microscope we detected foci of highly electron-dense granules, which were similar in distribution and structure to calcium salts stained with the von Kossa method. Changes in small and medium size blood vessels were observed.

Subcutaneous fat necrosis of the newborn: light, ultrastructural and histochemical microscopic studies

“…TaTeb et al (14) postulated that a deficiency in brown fat may be related to the development of SCFN because this fat is involved in the defense against hypothermia, and the disease usually involves the distribution of brown fat. Neurologic abnormalities, frequently encountered in SCFN, including paresis (as in the present case) (11), seizures (as in the present case) (6,8,12), and central nervous system injury (9), may impair heat production by brown fat cells either through abnormal p-adrenergic response to hypothermia or in relation to associated hypoxia from peripheral ischemia (13).…”

“…In studies of vascular injury in SCFN, Pasyk (9) and Taieb et al (14) noted that the veins in the dermis and in the intralobular septa of the subcutaneous fat had thickened walls and narrowed lumen. Ultrastructurally, capillaries and smaller blood vessels inside the fat lobules showed pathological changes of the endotheiium, some with total destruction of the vessel wall and of the basal lamina (9). In many capillaries, the endothelial cells possessed numerous microvilli, which may restrict the lumen and potentially influence metabolic functions.…”

“…SCFN is a lobular pannicuiitis characterized by a granulomatous reaction with an infiltrate consisting of foreign-body giant cells, fibroblasts, lymphocytes, and histiocytes (9,10). The fat released from a damaged adipocyte undergoes hydrolysis to glycerol and fatty acids; the latter produce a foreign-body giant cefl granulomatous reaction (9).…”

“…Light (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and ultrastructural (2,(9)(10)(11) microscopic features of SCFN have previously been described; histochemical studies, however, have not been reported. We present a patient with SCFN and examine the light, ultrastructural, and histochemical microscopic findings.…”

“…Subcutaneous fat necrosis of the newborn (SCFN) is an uncommon disorder of the panniculus characterized by crystallization and necrosis of adipocytes and an infiammatory foreign-body-like giant cell granulomatous reaction (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). It usually affects healthy full-term or postmature infants, and it ordinarily occurs in the first month of life.…”