Neonates may develop different types of panniculitis. While subcutaneous fat necrosis can be found in relatively healthy infants, sclerema neonatorum is associated with a significant mortality rate.
|
Clinical Features |
Subcutaneous Fat Necrosis |
Sclerema Neonatorum |
|
clinical status |
good health |
seriously ill (prematurity, hypothermia, major clinical illness) |
|
distribution |
localized; may be on trunk, extremities, buttocks, cheeks |
diffuse, may start on buttocks, trunk, shoulders or thighs |
|
lesions |
firm, purple-red subcutaneous nodules or plaques that are mobile and which become soft |
yellowish white, nonpitting, firm induration, often cold |
|
drainage |
occasional, with caseous material arising from fat necrosis |
none |
|
prognosis |
usually good; hypercalcemia associated with poor prognosis |
severity correlates with mortality; many infants die in a few days |
Occasional patients may show a mixed pattern with features of both syndromes.
|
Histologic Features |
Subcutaneous Fat Necrosis |
Sclerema Neonatorum |
|
needle-like clefts within lipocytes |
often present |
present; frozen sections show polarizable crystals |
|
inflammation |
lobular, may be granulomatous |
minimal or none |
|
fat necrosis |
present |
minimal |
|
calcium deposits |
may be present |
uncommon |
|
fibrosis |
diffuse |
broad, intersecting septae |
|
hemorrhage |
occasionally |
uncommon |
where:
• The needle-like clefts within lipocytes are formed when triglyceride crystals are dissolved during tissue processing.
• The histologic appearance of subcutaneous fat necrosis when needle-like clefts are absent resembles cold panniculitis.
• Polarizable crystals are seen in sclerema neonatorum if a frozen section is performed.
Differential diagnosis:
(1) cold panniculitis
(2) post-steroid panniculitis
Specialty: Dermatology
