A necrobiotic granuloma shows:
(1) a periphery consisting of a granulomatous reaction
(2) central necrobiosis (hypocellular with loss of elastic fibrers and with variable amounts of fibrin, lipid and mucin)
(3) absence of acute, chronic or caseous necrosis
A necrobiotic granuloma can heal without scarring..
A pallisading necrobiotic granuloma has histiocytes with elongated nuclei arranged in a radial pattern.
Conditions that can cause a necrobiotic granuloma include:
(1) granuloma annulare
(2) rheumatoid nodule
(3) actinic granuloma (annuolar elastolytic granuloma)
(4) nccrobiosis lipoidica
(5) rheumatic fever papule
(6) injection site (drug, vaccine, collagen)
(7) necrobiotic xanthogranuloma
