Histoplasmosis as a cause of nodular myositis in an AIDS patient diagnosed on fine needle aspiration cytology. A case report.

BACKGROUND

Histoplasmosis, extrapulmonary or disseminated, with positive HIV serology is an indicator of AIDS. Infection by Histoplasma capsulatum (HC) has been found on fine needle aspiration cytology (FNAC) in the lung, breast, adrenal, gastrointestinal tract, lymph nodes, subcutaneous tissues and other sites. We could not find any reports of isolated nodular myositis caused by HC and diagnosed on FNAC.

CASE: A 42-year-old, HIV-1-positive, heterosexual man presented with generalized myalgia, fever and multiple painful nodules in the skeletal muscles. The CD4 count was 66 cells per microliter. FNAC from multiple nodules contained numerous intracytoplasmic and a few extracellular, 3-5-microm, oval, pale yeasts, occasionally showing single budding with a narrow base. Morphology of the yeasts, as demonstrated by May-Grünwald-Giemsa and Gomori methenamine silver stain, was characteristic of HC. The patient's condition improved, and the nodules disappeared rapidly within 5 days of treatment with fluconazole, 400 mg daily.

CONCLUSION

The cytomorphology of HC is characteristic. An unusual presentation of rare infections can cause considerable diagnostic difficulties for both the clinician and cytopathologist. Awareness of these rarities is important to ensure optimal patient care. Thus, the role of FNAC is critical and remains unchallenged.