<prompt> Doughnut granuloma is a finding of :-RMSFQ feverLyme diseaseEhrlichiosis  <response>: A fibrin ring granuloma also known as doughnut granuloma is a histopathological finding that is characteristic of Q fever. On H E stain, fibrin ring granuloma consists of a central lipid vacuole surrounded by a dense red fibrin ring and epithelioid macrophages Fibrin ring granulomas may also be seen in Hodgkins disease and infectious mononucleosis. RMSF Rocky Mountain Spotted Fever is caused by Rickettsia rickettsii Lyme disease is caused by Borrelia burgdorferi Human monocytic Ehrlichiosis is caused by E. chaffenensis Human granulocytic Ehrlichiosis is caused by E. phagocytophilum. 