← All decks
Dermatology
Panniculitis
Built from Dermatology, 5th Edition
What’s inside
16 sections · 165 slides
Overview
- What panniculitis is
- Why panniculitis is hard to diagnose
- Conditions covered in this chapter
Classifying panniculitis
A working system for reading the pattern before naming the cause
- Two goals when treating panniculitis
- Septal versus lobular: the basic split
- Panniculitis pattern - the diagnostic split
- Different forms of panniculitis have favorite locations on the body.
- This flowchart moves from the biopsy pattern toward a short list of likely diagnoses.
- An approach to the histopathologic diagnosis of panniculitis
- An approach to the histopathologic diagnosis of panniculitis (continued)
- An approach to the histopathologic diagnosis of panniculitis (continued)
- Classification used in this chapter
- Classification of the panniculitides
Erythema Nodosum
The best known and most common form of panniculitis
- Erythema nodosum: key features
- History and epidemiology
- What triggers erythema nodosum
- The immune cascade behind erythema nodosum
- TNF and granuloma formation in erythema nodosum
- Causes of erythema nodosum
- Causes of erythema nodosum (continued)
- Causes of erythema nodosum (continued)
- Causes of erythema nodosum (continued)
- Causes of erythema nodosum (continued)
- Causes of erythema nodosum (continued)
- Nodules arise in crops and are tender to the touch.
- Bilateral shin and foot nodules of erythema nodosum
- Erythema nodosum arising with sarcoidosis
- Course and systemic signs
- Erythema nodosum lesions with a fading bruise-like color
- Findings that suggest a systemic cause
- Findings suggestive of a systemic cause for erythema nodosum
- Recurrence and chronic forms
- Erythema nodosum is the model 'septal' panniculitis - inflammation concentrates in the septa (walls) between fat lobules.
- Septal panniculitis with Miescher microgranulomas
- Distinguishing erythema nodosum from look-alikes
- First-line treatment of erythema nodosum
- Treatment recommendations for erythema nodosum
- Use of potassium iodide (KI)
- Treating erythema nodosum tied to another disease
Subacute Nodular Migratory Panniculitis
A chronic, spreading variant of erythema nodosum
- A chronic, migrating variant of erythema nodosum
- Pathology and treatment
Morphea/Scleroderma Panniculitis
When skin-hardening disease reaches down into the fat
- Fat involvement in morphea and systemic sclerosis
- Biopsy shows a septal panniculitis with thickened septa, sometimes with mucin (a gel-like connective tissue substance).
- Clinical and microscopic features of connective tissue panniculitis
- Clinical and microscopic features of connective tissue panniculitis (continued)
- Telling the connective tissue panniculitides apart
Alpha-1 Antitrypsin Deficiency Panniculitis
Ulcerating panniculitis from a missing protease inhibitor
- Alpha-1 antitrypsin deficiency panniculitis: key features
- History and epidemiology
- The SERPINA1 gene and protein deficiency
- How the deficiency damages fat and skin
- Other organs affected by alpha-1 antitrypsin deficiency
- Large, tender, red-to-purple nodules or plaques appear, especially on the lower trunk, flanks, buttocks, and thighs.
- Early disease shows a neutrophil-rich panniculitis that quickly destroys fat lobules.
- Distinguishing it from other ulcerating panniculitides
- Treatment of alpha-1 antitrypsin deficiency panniculitis
- Replacement therapy and newer options
Erythema Induratum
Leg nodules with vasculitis, historically tied to tuberculosis
- Erythema induratum: key features
- History and epidemiology
- What drives erythema induratum
- Tender, red-to-purple nodules and plaques develop most often on the calves.
- Erythema induratum is a lobular or mixed septal/lobular panniculitis.
- Differential diagnosis of erythema induratum
- Superficial thrombophlebitis mimicking panniculitis
- Treatment of erythema induratum
Pancreatic Panniculitis
A skin sign of pancreatic disease, driven by digestive enzymes
- Pancreatic panniculitis: key features
- Epidemiology and enzyme pathogenesis
- The pancreatic panniculitis mechanism
- Which pancreatic diseases can trigger this: acute or chronic pancreatitis, pancreatic cancer, pseudocysts, or pancreas divisum.
- Pancreatic panniculitis with postinflammatory skin changes on the arm
- Associated findings and Schmid's triad
- Even early lesions show fat necrosis with liquefaction and tiny cyst formation.
- Ghost cells and saponification in pancreatic panniculitis
- Differential diagnosis and treatment
Needle-Shaped Clefts: Three Neonatal Panniculitides
Sclerema neonatorum, subcutaneous fat necrosis, and post-steroid panniculitis
- Why infant fat crystallizes
- Three related entities, side by side
- Sclerema neonatorum: key features
- History, epidemiology, and mechanism
- Rapid hardening leads to firm, rigid skin over most of the body.
- Treatment of sclerema neonatorum
- Subcutaneous fat necrosis of the newborn: key features
- History, epidemiology, and triggers
- Smooth, circumscribed, mobile, red-to-violet nodules or plaques appear, sometimes symmetrically.
- Subcutaneous fat necrosis of the newborn on the trunk
- Thrombocytopenia and outcome
- Biopsy shows a predominantly lobular panniculitis with a mix of inflammatory cell types.
- Lobular panniculitis with radial needle-shaped clefts in giant cells
- Treatment of subcutaneous fat necrosis of the newborn
- Panniculitides with needle-shaped clefts in the subcutis
- Panniculitides with needle-shaped clefts in the subcutis (continued)
- Post-steroid panniculitis: key features
- History, epidemiology, and pathogenesis
- Clinical course, differential diagnosis, and treatment
Lupus Erythematosus Panniculitis
Deep lupus disease that can scar into visible dents in the skin
- Lupus panniculitis: key features
- History and epidemiology
- Immune mechanisms in lupus panniculitis
- Tender subcutaneous nodules and plaques arise in crops, often after a history of trauma to the site.
- Lupus panniculitis involving the orbital area
- Timing and lab findings
- Lupus panniculitis is a predominantly lobular process with variable inflammation.
- The most important look-alike: SPTCL
- Lupus panniculitis versus subcutaneous panniculitis-like T cell lymphoma (SPTCL) – distinguishing features
- Lupus panniculitis versus subcutaneous panniculitis-like T cell lymphoma (SPTCL) – distinguishing features (continued)
- Lupus panniculitis versus subcutaneous panniculitis-like T cell lymphoma (SPTCL) – distinguishing features (continued)
- Why the distinction from lymphoma matters
- Treatment of lupus panniculitis
Panniculitis of Dermatomyositis
An uncommon manifestation of a muscle and skin autoimmune disease
- Panniculitis of dermatomyositis: key features
- Pathology and differential diagnosis
- Treatment of dermatomyositis panniculitis
Traumatic Panniculitis
Fat inflammation from cold, injection, or blunt injury
- Four categories of traumatic panniculitis
- History of cold and injected-material panniculitis
- Who is affected, and why cold damages fat
- Injected substances that can trigger panniculitis
- In cold panniculitis, firm nodules develop, particularly on the cheeks and chin of infants.
- Named patterns of injection panniculitis
- Distinctive large vacuoles (empty-looking spaces) are seen in the dermis and subcutis on biopsy.
- Microscopic features of traumatic panniculitis
- Microscopic features of traumatic panniculitis (continued)
- Differential diagnosis and treatment
Lipodermatosclerosis
Fibrosing panniculitis of the lower leg driven by venous disease
- Lipodermatosclerosis: key features
- History and epidemiology
- Venous hypertension and vessel injury
- Other contributing factors
- Acute phase brings pain, warmth, redness, and some induration, most often above the inner ankle.
- Membranocystic change - the key pathology clue
- Membranocystic change shows as cystic spaces lined by thickened, folded (papillary) membranes.
- Differential diagnosis of lipodermatosclerosis
- Treatment of lipodermatosclerosis
Infection-Induced Panniculitis
When a wide range of organisms attack the fat directly
- Infection-induced panniculitis: key features
- History and how organisms reach the fat
- Infection-induced panniculitis – reported causative agents
- Infection-induced panniculitis – reported causative agents (continued)
- Patients develop local swelling and redness, with one or more fluctuant nodules that can ulcerate and drain.
- Unusual patterns by organism
- Differential diagnosis and treatment
Cytophagic Histiocytic Panniculitis and Malignant Infiltrates
When 'panniculitis' is really a lymphoma in disguise
- Cytophagic histiocytic panniculitis (CHP)
- Subcutaneous nodules appear, often with purpura (small areas of bleeding under the skin).
- Macrophages engaged in cytophagic activity are the histologic hallmark.
- Malignant infiltrates that mimic panniculitis
- Histopathologic clues to malignancy
Drug-Induced and Unusual Forms
An expanding list, especially with newer targeted cancer therapies
- Drug-induced panniculitis
- Drug-induced panniculitis
- Drug-induced panniculitis from targeted cancer therapy
- An expanding list of unusual panniculitides
- Unusual or recently described forms of panniculitis
- Unusual or recently described forms of panniculitis (continued)
- How to work up an unidentified panniculitis
- Key takeaways
- References
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- Dermatology, 5th Edition (2-Volume Set)