Diagnosis of histoplasmosis on lymph node fine needle aspiration cytology utilizing Giemsa stain: a report of three cases.

Background: Histoplasmosis is a fungal infection caused by Histoplasma capsulatum; it mostly occurs in immunocompromised individuals. Disseminated histoplasmosis may affect almost all systems. The lymph node is frequently involved in the reticuloendothelial dissemination. Histoplasmosis of the lymph node can mimic tuberculosis clinically and cytomorphologically. Fine needle aspiration cytology (FNAC) is an effective method for differentiating the two. The histoplasma yeast forms are small and usually intracellular and are likely to be overlooked in Papanicolaou (Pap)-stained smears. Air-dried Giemsa-stained smears can identify them easily and clearly because of their large size and bright purple-to-blue color as compared with fixed Pap-stained smears.

Cases: We report 3 cases of lymph node histoplasmosis diagnosed on cytology seen over a period of 2 years.

Conclusion: Lymph node FNAC is a rapid, cost-effective, reliable diagnostic toolfor histoplasmosis. It can obviate the need of surgical biopsy and hasten the initiation of treatment.