Subcutaneous fat necrosis of the newborn: clinical and histopathological correlation

Abstract

Subcutaneous fat necrosis of the newborn is a rare benign panniculitis found in term and post-term neonates. Diagnosis is based on clinical characteristics and specific alterations in the adipocytes, detected by anatomical pathology. Subcutaneous fat necrosis of the newborn can occur in uncomplicated pregnancy and childbirth. However, perinatal complications such as asphyxia, hypothermia, seizures, preeclampsia, meconium aspiration, and even whole-body cooling used in newborns with perinatal hypoxia/anoxia may be associated with this entity.

Clinicopathological features of neonatal subcutaneous fat necrosis and its implications

“…It is postulated that subcutaneous tissue hypoperfusion aggravates the deposition of saturated fatty acids, and because the system enzymes are immature there is increasing deposition of saturated fatty acids, leading to adipose tissue solidification and necrosis. The local pressure resulting from childbirth trauma can increase the tendency to fat necrosis [3].…”

“…The most important differential diagnosis is sclerema neonatorum, a disorder in which there is a thickening of the skin secondary to fibrosis of the trabecular septa of the adipocytes' involvement of the muscle and bone tissue, associated with congenital malformations, cyanosis, respiratory disorders, and sepsis [3]. Another differential diagnosis is scleredema, which presents progressive oedema of the extremities and stiffening of the affected limbs, usually preceded by gastrointestinal or respiratory infections; pathology reveals intense interstitial oedema associated with lobular panniculitis without vasculitis.…”

Sclerema Neonatorum in a Term Infant: A Case Report and Literature Review

“…Definitive diagnosis of SN requires a histopathological study. Histology evaluation of skin biopsy shows thickening of the trabeculae supporting the subcutaneous adipose tissue and a sparse infiltration of lymphocytes, histiocytes, and multinucleate giant cells, which is attributable to a poor immunological response [ 7 , 14 ]. In addition, subcutaneous fibrosis, thinning of the epidermis, atrophy of the rete pegs, dense deposition of collagen in the dermis [ 15 ], and fine, needle-shaped crystals may be observed in adipocytes [ 13 , 16 , 17 ].…”

“…The lesions move freely, are not attached to muscles and bone, and generally do not spread beyond the initial areas of involvement [ 19 ]. SCFN usually occurs within the first 7 days in term and postterm infants [ 14 , 18 , 20 ]. SN should also be distinguished from scleredema, a self-limiting condition with an onset during the first week of life, invariably affecting preterm neonates.…”

Calcium management challenges in a macrosomic child with subcutaneous fat necrosis

“…Tissue hypoxia plays a role in the pathophysiology of fat necrosis 1. This leads to preferential shunting of blood away from skin and towards the brain, heart and adrenal glands.…”