Panniculitis

Question 1

Panniculitis DDX

Answer 1

1. erythema nodosum (septal)
2. pancreatic fat necrosis
3. lipodermatosclerosis
4. Needle shaped clefts
   
   • Sclerema neonatorum (lipocytes with radial crystals and minimal inflammation)
   • Subcutaneous fat necrosis of the newborn (lipocytes with radial crystals and giant cells/inflammation)
   • Post-steroid panniculitis (need history)
5. SQ reative lymphoid follicles
   
   • Lupus profundus
   • Reactive lymphoid hyperplasia, Bcell pseudolymphoma
   • Marginal zone B-cell lymphoma

Question 2

Erythema nodosum

Answer 2

Septal pattern

neutrophils in septum in acute phase

mononuclear cells and granulomas in chronic phase

Miescher’s radial granulomas (central cleft within granuloma)

Normal epidermis and dermis

Question 3

Pancreatic fat necrosis

Answer 3

Need clinical history

Neutrophils

necorsis of the fat lobule with calcium soap outlining necrotic lipocytes

Calcification

Question 4

Lipodermatosclerosis

Answer 4

AKA sclerosing panniculitis

1. septal and lobular, lipomembranous fat necrosis
2. Cystic degeneration (dilated, irregular with hemosiderin)
3. stasis dermatitis (hyalinized fat membranes)