fibrin-ring granuloma

Definition: Fibrin ring or "doughnut" granulomas are small, non-necrotizing granulomas with a very distinctive appearance that are usually found in the liver and bone marrow in patients with Q fever. These granulomas characteristically contain a ring-like structure consisting of fibrinoid material; they may or may not have a centrally located fat vacuole(s).

Localization

 hepatic fibrin-ring granuloma
 medullary fibrin-ring granuloma

Etiology

 rickettsiosis

• Q fever (Coxiella burnetti )
• boutonneuse fever
• staphylococcal infection
• Lyme disease

 viral infections

• cytomegalovirus infection (CMV infection )
• hepatitis A
• Epstein-Barr virus infections (EBV infections )
  • infectious mononucleosis

 protozoal infections

• visceral leishmaniasis
• disseminated toxoplasmosis

 drug reactions

• allopurinol hypersensitivity
• checkpoint inhibitor-induced hepatitis

 dysimmune diseases

• systemic lupus erythematosus
• giant-cell arteritis

 tumors

• Hodgkin lymphomas
• non-Hodgkin lymphomas

See also

 granulomas