DISSEMINATED HISTOPLASMOSIS - ABDOMINAL CT FINDINGS IN 16 PATIENTS

Since the onset of the AIDS epidemic, disseminated Histoplasma capsulatum infection has been reported with much greater frequency in both endemic and nonendemic areas. Abdominal CT scans of 16 patients with disseminated histoplasmosis were reviewed retrospectively to identify radiologic features of this disease. The diagnosis was confirmed by autopsy (three patients), bone marrow biopsy (10 patients), lymph node biopsy (three patients), bronchoscopic biopsy (three patients), liver biopsy (two patients), and/or colonoscopic biopsy (one patient). Fourteen patients had serologic evidence of human immunodeficiency virus infection. Disseminated histoplasmosis was either the only initial manifestation of AIDS (seven patients) or was accompanied simultaneously by cytomegalovirus infection (four patients), or Kaposi sarcoma, Toxoplasma encephalitis, or cryptosporidiosis (one patient each). Abdominal CT findings included hepatomegaly (63%); splenomegaly (38%); diffuse splenic hypoattenuation (19%); bilateral adrenal enlargement or hypoattenuating masses (13%); and enlarged lymph nodes with homogeneous soft-tissue density (44%), diffuse or central low density (13%), or both (19%). Histoplasmosis should be included in the differential diagnosis when abdominal CT scans show such nonspecific findings as hepatomegaly, splenomegaly, enlarged soft-tissue-density or hypoattenuating lymph nodes, or adrenal enlargement or masses in an immunodeficient patient. An uncommon but possibly specific CT finding in histoplasmosis is diffuse splenic hypoattenuation.