Granulomatous hepatitis in Q fever.

Liver lesions in 17 patients with serologically diagnosed Q fever are described. A distinctive granulomatous pattern, with granuloma formation plus a fibrinoid ring, was observed in 14 cases. In two cases the fibrinoid material consisted of fibrillar eosinophilic structures without an annular arrangement, interspersed among epithelioid cells. In only one case was a nonspecific granuloma (devoid of fibrinoid material) noted. We conclude that the association of a granuloma with fibrinoid material is highly indicative of Q fever, but serial sections are often necessary to demonstrate this pattern.