A Dual-Modality Ultrasound (EBUS and EUS) Approach to Diagnose Pulmonary Histoplasmosis

Abstract

INTRODUCTION: A dual-modality approach utilizing endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) & endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) can comprehensively stage lung cancer and can be used in the diagnosis of non-neoplastic adenopathy. We present a patient with diffuse adenopathy in which a dual-modality ultrasound approach was used to diagnose disseminated pulmonary histoplasmosis. CASE PRESENTATION: Our patient is a 25 year-old medical student who presented with malaise, fatigue, night sweats and low-grade fever one week after returning from Honduras. He also endorsed weight loss, frontal headache and rigors. Physical examination revealed a temperature of 100.4 degreeF and normal breath sounds. His leucocyte count was 35, 00 with 16% bands and a platelet count of 124,000. A peripheral smear was performed and was negative for malaria. Serology was also negative for dengue, rickettsia and ehrlichia. Chest radiograph revealed bilateral hilar adenopathy and a contrast-enhanced CT scan of chest and abdomen revealed patchy alveolar infiltrates, splenomegaly and mediastinal, hilar and celiac adenopathy. Our patient was then scheduled for a EUS-FNA, flexible bronchoscopy with bronchoalveolar lavage (BAL), transbronchial lung biopsy and EBUS-TBNA. EUS-FNA revealed extensive celiac adenopathy which was aspirated for cytology and staining. Flexible bronchoscopy revealed normal airways and a transbronchial lung biopsy was then performed. EBUS revealed enlarged subcarinal adenopathy which was aspirated. Cytology of celiac adenopathy revealed non-caseating granulomas and subsequent silver stain identified small yeast forms with narrow-based budding which confirmed dissemination. Cytology on alveolar tissue and subcarinal adenopathy also revealed non-caseating granulomas. Based on the morphological appearance of yeast forms and patient's positive urine histoplasma antigen, empiric therapy with itraconazole was initiated with clinical improvement. Fungal culture from BAL eventually grew Histoplasma capsulatum. DISCUSSION: Among the endemic mycoses, histoplasmosis is the most common cause for hospitalization1. A delay in diagnosis may compromise patient care and increase morbidity. Cytologic examination of lymph node tissue using special stains that highlight fungi permit rapid diagnosis of histoplasmosis2. Fungal culture can take up to 6 weeks and has a low sensitivity in acute disease 3. We present a patient where a dual modality approach was successfully used to diagnose disseminated histoplasmosis. CONCLUSION(S): Dual modality EUS & EBUS can provide rapid cytological diagnosis of adenopathy due to histoplasmosis.