Skin nontumor


Subcutaneous fat necrosis of newborn

Last author update: 1 August 2011
Last staff update: 28 August 2020

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PubMed Search: Subcutaneous fat necrosis of newborn

Mowafak Hamodat, M.B.Ch.B., M.Sc.
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Cite this page: Hamodat M. Subcutaneous fat necrosis of newborn. website. Accessed September 27th, 2023.
Definition / general
  • Uncommon disorder of infants in good health with lesions on trunk, extremities, buttocks, cheeks
  • Hypercalcemia has been reported in some cases; thrombocytopenia, hypoglycemia and hypertriglyceridemia may also develop
  • Lactic acidosis and hyperferritinemia were each present in one case
  • Numerous possible causes, including obstetrical trauma, hypothermia, asphyxia, anemia, forceps delivery, macrosomia, exposure to active or passive smoking during pregnancy, prostaglandin E administration, maternal exposure to cocaine or calcium channel blockers
Clinical features
  • Indurated areas and distinct nodules with a predilection for the cheeks, shoulders, buttocks, thighs and calves
Case reports
Microscopic (histologic) description
  • Basophilic fat necrosis, clusters of needle like clefts in lipocytes and histiocytes
  • Clefts may contain refractile crystals
  • Variable granulomatous inflammation and small calcium deposits
  • Normal epidermis and dermis with an underlying lobular panniculitis
  • Focal fat necrosis is present and this may lead to fat cyst formation
  • Lymphocytes, histiocytes, foreign body giant cells and sometimes a few eosinophils wedged between the fat cells
  • Many fat cells retain their outline but contain fine, eosinophilic cytoplasmic strands and granules, between which are narrow clefts radiating from a point near the periphery of the cell; clefts contain doubly refractile crystals, representing triglycerides, on frozen section
  • Similar fine, needle-like crystals can be seen in giant cells
  • Older lesions have fibrosis between fat cells
Electron microscopy description
  • Intact and necrotic fat cells containing needle-shaped crystals arranged radially or in parallel
  • Dense granular material is also present in necrotic fat cells, which are surrounded by macrophages
Additional references
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