Granuloma Annulare
Christine J. Ko, MD
Key Facts
Clinical Issues
Most commonly localized over backs of hands/feet or on arms/legs
Pink-red to slightly brown or purple 1-2 mm papules in annular arrangements of 1-5 cm in diameter
Microscopic Pathology
Interstitial pattern
“Busy” dermis of interstitial histiocytes, perivascular lymphocytes
Palisaded pattern
Central mucin with surrounding palisade of histiocytes
Top Differential Diagnoses
Interstitial pattern
Interstitial granulomatous dermatitis
Palisaded pattern
Annular elastolytic giant cell granuloma
Rheumatoid nodule
 This photograph of granuloma annulare shows annular arrangements of pink papules on the dorsal hand. There is no surface scale. (Courtesy Yale Residents’ Collection.) |
 Granuloma annulare typically shows a palisade of histiocytes  around central mucin  . There is a perivascular lymphocytic infiltrate. |
TERMINOLOGY
Abbreviations
Granuloma annulare (GA)
Synonyms
Deep GA = pseudorheumatoid nodule
Definitions
Idiopathic granulomatous skin disease
CLINICAL ISSUES
Epidemiology
Age
More common in children/young adults
Gender
More common in females
Site
Most commonly over backs of hands/feet or on arms/ legs
