Doughnut Granuloma

(redirected from Ring Granuloma)
A granuloma composed of epithelioid histiocytes, neutrophils, mononuclear or ‘round’ inflammatory cells, giant cells, and a central cleared lipid vacuole; while a characteristic finding in Q fever—Coxiella burnetii—the doughnut granuloma occurs in less than half of the cases, located in the bone marrow and liver; doughnut granulomas are also seen in human monocytic ehrlichiosis due to Ehrlichia chaffeensis, Hodgkin’s disease, infectious mononucleosis, typhoid and CMV in immunocompromised patients
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Scattered S100-positive histiocytes were seen in the ring granulomas, indicating scattered Langerhans accessory cells with numerous reactive histiocytes (results not shown).