Histoplasma Lymphadenitis

Related Cases: HP-0315

Clinical Futures

  • Histoplasma capsulatum, central America and river valleys of midwestern and south-central USA

  • Immunocompetent patients: Pulmonary infection, mild or no symptoms

  • Immunocompromised hosts: Disseminated or fatal infection; lymph node involvement as part of disseminated disease

Microscopic Findings

  • Cytology on touch imprint or smear: Small fungi in histiocytes, 2-4 um; nuclei, and halo effect; occasional narrow-based budding

  • Lymph node architecture distorted or effaced by sheets of histiocytes and inflammatory reaction

  • Histiocytes contain multiple small, round, unstained intracytoplasmic vacuoles

  • Granulomas and giant cells may be present

  • Fungi positive for GMS and PAS stains

Differential Diagnosis

  • Leishmanial Lymphadenopathy

    • Very rare

    • Travel history, exposed to sand fly

    • Often skin lesions

    • Intracellular microorganisms: 2-4 um, kinetoplasts, no halo

    • IHC, serology and molecular studies to confirm the parasite



Last update: 10/06/2017