Skin nontumor
Panniculitis
Panniculitis
Topic Completed: 1 August 2011
Minor changes: 28 August 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Panniculitis [title] skin
Cite this page: Hamodat M. Panniculitis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorpanniculitis.html. Accessed December 3rd, 2021.
Definition / general
- Inflammation of subcutaneous fat affecting connective tissue septa separating lobules, usually in lower legs
- Poorly defined, tender, erythematous nodules
- Variable fever, malaise
- Lesions are transient
- Either septal (involving fibrous septa) or lobular (involving lipocyte lobules)
- Inadequate biopsy specimens, particularly punch biopsies, may include no subcutaneous fat, and make diagnosis difficult if not impossible
- Lobular panniculitis: due to nodular vasculitis (erythema induratum), subcutaneous fat necrosis of newborn, pancreatic fat necrosis, lupus panniculitis, physical and factitious panniculitis, other
- Lupus panniculitis: also called lupus profundus; may develop in normal skin or preexisting skin lesion of patient with systemic or discoid lupus erythematosus
- Physical and factitious panniculitis: due to blunt force, pinching, cold or injection of foreign substances for secondary gain; a diagnosis of exclusion
- Septal panniculitis: due to erythema nodosum or alpha-1-antitrypsin deficiency
Case reports
- 45 year old woman (Dermatol Online J 2001;7:20)
Microscopic (histologic) description
- Lupus panniculitis: vacuolar interface change and lymphoid infiltrates in dermis in lupus-related lesions; in non lupus-related skin lesions, see ghost cells due to loss of nuclei and basophilic material replacing cell membranes, causing basophilic sclerosis of lobules; dense lymphoplasmacytic infiltrates in lobules and septa; variable dermal and septal mucin; fibrosis over time
- Septal panniculitis: lobular neutrophils, variable focal fat necrosis; refractile material may be present if substances were injected
