Granulomatous diseases

Granuloma Annulare (GA) (Figure 3.14A–C)
  • Asymptomatic, benign and self-limited granulomatous disease of the dermis seen in both adults and children
  • Unknown etiology; may include trauma and sun exposure
  • Presents as skin-colored to pink non-scaly papules coalescing into annular or arciform plaques, typically over dorsal hand or foot; variants listed below:

  •    
     
    GA VariantDescription
     
    Patch GA
    (Macular)
    Patches of erythema typically over extremities ± trunk
     
    Generalized GA
    (Disseminated)
    Flesh-colored pink papules over trunk/extremities; poor response to treatment; association with diabetes
     
    Perforating GA
    Small papules with central umbilication and crusting (discharging necrotic collagen) typically over dorsal hands
     
    Subcutaneous GA
    Deep dermal nodules similar to rheumatoid nodules;
    typically asymptomatic
     
       

  • Histology: necrobiotic foci in dermis surrounded by histiocytes (palisading granulomas) or histiocytes splayed between collagen bundles (interstitial type), mucin accumulation, ± perivascular lymphocytes/eosinophils
  • Treatment: clinical observation as typically self-limited (50–75% of cases with resolution in 2 years) in localized GA, potent topical corticosteroid or intralesional corticosteroid
Figure 3.14 A: Granuloma annulare B: Granuloma annulare (Courtesy of Dr. Paul Getz) C: Subcutaneous GA (Courtesy of Dr. Paul Getz)
Figure 3.14
A: Granuloma annulare
B: Granuloma annulare
(Courtesy of Dr. Paul Getz)
C: Subcutaneous GA
(Courtesy of Dr. Paul Getz)
 
Figure 3.15 A: Necrobiosis lipoidica (Courtesy of Dr. Sophie M. Worobec) B: Necrobiosis lipoidica (Courtesy of Dr. Paul Getz) C: Necrobiotic xanthogranuloma (Reprint from Morgan MB, Smoller BR, Somach SC. Deadly Dermatologic Diseases. New York, NY: Springer; 2007)
Figure 3.15
A: Necrobiosis lipoidica
(Courtesy of Dr. Sophie M. Worobec)
B: Necrobiosis lipoidica
(Courtesy of Dr. Paul Getz)
C: Necrobiotic xanthogranuloma
(Reprint from Morgan MB, Smoller BR, Somach SC. Deadly Dermatologic Diseases. New York, NY: Springer; 2007)