Granulomatous Dermatitis Flashcards
Granulomatous patterns
- Palisaded
- Sarcoidal
- Tuberculoid
- Foreign body type
Granulomatous dermatitis DDX
- Granuloma annulare
- Necrobiosis lipoidica diabeticorum
- Necrobiotic xanthogranuloma
- Rheumatoid nodule
- Sarcoidosis
- Tuberculosis, atypical mycobacterial infections
- Foreign body reaction
Foreign body reaction
“holy” pattern (parrifin, silicone) or ruptured hair follicle/cyst material
Tuberculosis, atypical mycobacteria
Lymphocytes surrounding granulomas
Abundant histiocytes
May have neutrophils (esp early on)
Central necrosis
AFB, fite, cultures
Sarcoidosis
naked granulomas with scattered lymphs
No necrosis
May have asteroid bodies or Schaumann bodies
Rheumatoid nodule
Deep dermal or SQ nodule
Palisaded histiocytes with fibrin in center
Lymph and PCs
No mucin
More eosinophilic than GA and lacks mucin
Necrobiotic xanthogranuloma
Broad areas of necrobiosis and granulomas
Large, atypical multinucleated cells
Cholesterol clefts
No mucin
Necrobiosis lipoidica diabeticorum (NLD)
Broad palisaded (lasagna like) layers of necrobiosis
Not as discrete as GA
Lacks mucin
Granuloma annulare
Palisaded histiocytes surrounding foci of necrobiosis
few neuts or eos
Mucin present
Deep and interstitial forms
DDX:
- NLD (broad, parallel layers of necrobiosis)
- Epithelioid sarcoma (necrosis, atypical cells)
