[368] Histoplasmosis: Have EUS and EBUS FNA Changed the Cytologic Face of the Disease?

Michael P Gailey, Chris S Jensen. University of Iowa Hospitals and Clinics, Iowa City, IA

Background: Cytologic diagnosis of histoplasmosis is well-described and most series and reports focus on immunosuppressed patients with disseminated disease. However, with the advent of ultrasound-guided (US) fine needle aspiration (FNA) techniques, especially endoscopic (EUS) and endobronchial (EBUS) modalities, we have noted a marked increase in the cytologic diagnosis of histoplasmosis in immunocompetent patients.
Design: A computer search identified cytology cases with Histoplasma present in the past 10 years. All cases in which cytology material was available were included in this study, along with patient demographic, clinical and laboratory data.
Results: Forty cases of histoplasmosis (all FNA; 30 EBUS, 8 EUS, 2 US) were identified. The patients ranged from 15-86 years (mean 42); 22 female; 18 male; 36 of 40 (90%) patients were immunocompetent; only four were immunocompromised. Fourteen patients were being staged for primary tumors of other sites; others presented with primary pulmonary symptoms or were noted incidentally. Sites included lung and mediastinum (19), lymph nodes (18), adrenal gland (1), right neck (1), thyroid bed (1). The character of the specimens in all patients included: bland acellular necrosis with (31) or without (9) granulomas. In immunocompetent patients very rare intracellular organisms were seen on rapid or routine stains (Diff Quik and Pap) with variable (rare to many) extracellular organisms on GMS stain; a conspicuous neutrophilic infiltrate and giant cells were only occasionally seen (3 and 4 cases, respectively). In immunosuppressed patients the character of the necrosis was similar, but many more organisms were identified. Fungal cultures were negative in all patients except one (immunosuppressed; blood). Histoplasma yeast antigen (by compliment fixation, CF) was undetectable (<1:8) in 8/21 (sensitivity 61.9%)) and the mycelial antigen (CF) was undetectable in 20/21 (95.3%). Histoplasma urine antigen was detected in only 2/17 (11.8%).
Conclusions: 1. Disseminated histoplasmosis diagnosed cytologically has abundant intracellular organisms apparent on routine cytologic stains and confirmed on fungal stains.
2. Histoplasmosis in immune competent patients is characterized cytologically by bland necrosis with or without granulomas and requires fungal stains for diagnosis.
3. Urine and serum antigen tests have a low sensitivity (11.8% and 61.9%, respectively).
4. EUS and EBUS likely account for the increased cytologic diagnosis of histoplasmosis in immune competent patients, as nearly all of our cases were by these modalities.
Category: Cytopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 67, Monday Afternoon

 

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