Panniculitis
Panniculitis is inflammation of the adipose tissue. It is encountered in dermatopathology specimens.
General DDx
- Erythema nodosum.
- Erythema induratum.
- Self-inflicted trauma.
- Systemic lupus erythematosus.
- Weird stuff.
Specific conditions
Erythema nodosum
Causes - mnemonic NODOSUM:[1]
- NO cause (idiopathic) ~ 55% of cases.
- Drugs (sulfonamides, amoxicillin, oral contraceptives) ~ 5% of cases.
- Other infections - group A streptococci (streptococcal pharyngitis), Yersinia, chlamydia, mycobacteria, others ~ 30% of cases.
- Sarcoidosis ~ 7% of cases.
- Ulcerative colitis & Crohn's disease ~ 2% of cases.
- Malignancy (leukemia, Hodgkin's lymphoma) ~ 1% of cases
Microscopic
- Expanded septa between fat lobules - key (low power) feature.
- Neutrophils.
- Lymphocytes.
- Histiocytes.
- Fibrin.
Notes:
- No vasculitis.
- +/-Granulomas.[5]
Images:
Erythema induratum
General
Features:[3]
- Uncommon.
- Etiology: unknown.
Clinical:[4]
- Classic location: posterior shins.
- Ulcerates and scars.
Microscopic
Features:[3]
- Predominantly lobular process with:[2]
- Necrotizing granulomatous inflammation.
- Necrotizing vasculitis of small/medium sized vessels (early).
DDx:
- Infection.
Images:
See also
References
- ↑ 1.0 1.1 Schwartz, RA.; Nervi, SJ. (Mar 2007). "Erythema nodosum: a sign of systemic disease.". Am Fam Physician 75 (5): 695-700. PMID 17375516.
- ↑ 2.0 2.1 URL: http://www.medscape.com/viewarticle/440356_8. Accessed on: 11 September 2011.
- ↑ 3.0 3.1 3.2 Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1199. ISBN 978-1416031215.
- ↑ 4.0 4.1 Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 609. ISBN 978-1416054542.
- ↑ 5.0 5.1 URL: http://missinglink.ucsf.edu/lm/DermatologyGlossary/erythema_nodosum.html. Accessed on: 11 September 2011.