5  Non-tumorous skin diseases

5.11  Panniculitis

5.11.1  Erythema nodosum

Etiology, pathogenesis:

  • triggered by infection, drugs...
  • probably immonologic in basis

Clinical signs:

  • dome shaped nodules, especially on lower limbs, but sometimes on the thighs and upper extremities
  • palpable subcutaneous nodules, size over 1 cm
  • red or purple color
  • tender or painful on palpation
  • never ulcerate
  • self-limited, nodules eventually heal
  • peak incidence in women, 3rd decade


Erythema nodosum:
Erythema nodosum, CLINIC (730)

Erythema nodosum:
Erythema nodosum, CLINIC (731)

Erythema nodosum:
Erythema nodosum, CLINIC (732)

Erythema nodosum:
Erythema nodosum, CLINIC (2916)

Erythema nodosum:
Erythema nodosum, CLINIC (2917)

Erythema nodosum, CLINIC (2918)

Further examples of erythema nodosum:


Inflammation of fibrous septa between fat lobules; variably spreading into the lobules. Lymphocytes and macrophages dominate, neutrophils are often admixtured. Giant cells of foreign body type are located around clefts in collagen. Miescher granuloma is formed by more or less radially arranged macrophages, often around cleft like defects of dermal collagen.

5.11.2  Panniculitis arteficialis (factitial)

Clinical signs:

  • caused by the patient
  • usually within reach
  • variable picture, not corresponding to any defined disease


Panniculitis, usually with neutrophils and often with eosinophils, sometimes foreign substances or oily material can be found within the tissue.

5.11.3  Calcifying panniculitis

Clinical signs:

  • patients with renal disease or hyperparathyreoidism
  • deep nodules and plaques, indurated


Calcified arterial walls, calcifications of the fat.

5.11.4  Panniculitis caused by cold

Clinical signs:

  • nodules, plaques
  • develop after exposure to cold
  • resolves spontaneously after several weeks


Subcutaneous infiltrate with lymphocytes, histiocytes, usually with neutrophils and sometimes with eosinophils

5.11.5  Eosinophilic panniculitis

Clinical signs:

  • occurs in various diseases, where eosinophils are present


Subcutaneous infiltrates containing many eosinophils.

5.11.6  Lipomembranous panniculitis

Clinical signs:

  • may develop in ischemic tissues in patients with diabetes and ischemia of lower legs
  • deep indurated plaques


Pannniculitis with spaces, lined by PAS positive, eosinophilic layer with tiny projections, lipomembrane.

5.11.7  Traumatic panniculitis

Clinical signs:

  • at the sites of trauma
  • painful nodules, hemorrhage


Variable necrosis of the fat, foam cells; inflammation, sometimes with neutrophils; hemorrhage.

5.11.8  Panniculitis caused by steroids

5.11.9  Pancreatic panniculitis


  • accompanies enzymatic pancreatitis
  • necroses of the subcutaneous fat (similar to peritoneal necroses of Balser)


Areas of subcutaneous enzymatic necroses (loss of structure, ghost cells, eosinophilia of necrotic tissue, irregular shape); surrounded by reactive inflammatory infiltrate with neutrophils. Variable basophilic calcium deposits are present.

5.11.10  Other panniculitides


Panniculitides are divided into septal (some are accompanied with vasculitis), like erythema nodosum or necrobiosis lipoidica, and lobular, like vasculitis nodularis, subcutaenous sarcoidosis and others.

Clinical signs:

  • anywhere in subcutaneous tissue, often on lower extremities
  • soft subcutaenous nodules, skin is inflammed, reddish
  • sometimes tender or painful
  • some panniculitides may perforate (pancreatic panniculitis)


Panniculitis, chest:
Panniculitis, CLINIC (857)


Inflammation, sometimes granulomatous.


Granulomatous panniculitis:
Granulomatous panniculitis, HE 20x (5149)

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