Subcutaneous fat necrosis of the newborn



## Subcutaneous fat necrosis of the newborn##

  • Fat necrosis is a rare, self-limited process that usually occursin otherwise healthy full-term and post-mature infants
  • Seen with t otal body cooling for HIE .
  • Discrete firm red or hemorrhagic nodules and plaques up to 3 cm in diameter appear most commonly over areas exposed to trauma, such as the cheeks, back, buttocks, arms, and thighs , during the first few weeks oflife.
  • Lesions are usually painless, but marked tenderness may be present.
  • Although the cause is u nknown, difficult deliveries, hypothermia,perinatal asphyxia, and maternal diabetes predispose tothe development of fat necrosis, suggesting a role for mechanical,cold, and hypoxic injury to fat.
  • Nodules usually re solve without scarring in 1–2 months .
  • Variable amounts of calcification develop and can beappreciated radiographically.
  • Even in uncomplicated cases and occasionally after the lesions have resolved, hypercalcemia can develop 1–4 months after the initial detection of subcutaneous fatnecrosis.
  • Infants may present with nephrocalcinosis, poor weightgain, irritability, and seizures .
  • More rarely, thr ombocytopenia, hyperlipidemia, and hyperglycemia may also occur.
  • Histopathology demonstrates nec rosis of fat with a foreignbody giant cell reaction .
  • Remaining fat cells contain ne edle shaped clefts , and calcium deposits are scattered throughout the subcutis.