The pathologic spectrum of gastrointestinal and hepatic histoplasmosis

We characterized the pathologic spectrum of lesions in gastrointestinal and hepatic histoplasmosis by studying cases of disseminated disease in immuno compromised and immunocompetent patients from endemic and nonendemic areas. We evaluated 56 specimens from 52 patients with H&E and silver stains. Of these patients, 43% presented with gastrointestinal rather than pulmonary s ymptoms. Thirty-one percent had gastrointestinal lesions, 10% had liver les ions, and 43% had both. Gross gastrointestinal features included ulcers (49 % of patients), nodules (21%), hemorrhage (13%), obstructive masses (6%) an d normal mucosa (23%). Microscopic gastrointestinal findings included diffu se lymphohistiocytic infiltration (83%), ulceration (45%), lymphohistiocyti c nodules (25%), or minimal inflammatory reaction (15%) but only rare well- formed granulomas (8.5%). The most common hepatic finding was portal lympho histiocytic inflammation; discrete hepatic granulomas were seen in less tha n 20% of involved livers. The pathologist must be aware of the broad range of gastrointestinal and hepatic lesions produced by histoplasmosis and in p articular that well-formed granulomas are rare. Given the appropriate clini cal context histoplasmosis should be considered in both immunocompetent and immunocompromised patients, regardless of pulmonary symptoms, in nonendemi c as well as endemic areas.