A 44-year-old woman, lifelong resident of the northern suburbs of NYC, with a past medical history of polycystic ovarian syndrome was referred to our institution after a 9mm right lower lobe (RLL) pulmonary nodule (PN) was detected incidentally on computed tomography (CT) of the abdomen performed for nephrolithiasis. Review of systems was negative for constitutional and respiratory symptoms. She was a never-smoker and denied relevant occupational exposures. Vital signs, physical examination, and routine laboratory evaluation were unremarkable. Testing for the human immunodeficiency virus (HIV) and an interferon-gamma release assay for Mycobacterium tuberculosis (IGRA-MTB) were both negative. Chest CT performed five months after the abdominal study revealed an increase in size of the solid RLL PN to 11mm (Fig. 1) along with mediastinal and right hilar lymph nodes all measuring less than 1cm in short axis. Neither the PN nor the intrathoracic lymph nodes demonstrated avidity for 18fluorodeoxyglucose (18FDG) on 18FDG-positron emission tomography (18FDG-PET). Cytology from endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of the right hilar lymph node revealed a mixed cellular population consisting of lymphocytes and neutrophils against a background of extensive necrosis. No organisms were seen on lymph node cytology; bronchoscopic cultures returned negative for bacterial, mycobacterial, and fungal organisms. With the leading pre-operative diagnosis of neoplasia, the patient underwent wedge resection of the PN via video-assisted thoracoscopic surgery. Tissue examination revealed necrotizing granulomatous inflammation associated with small yeast-like forms exhibiting narrow-based budding, morphologically consistent with H. capsulatum (Fig. 2). Fungal cultures of the resection specimen yielded no growth. Antibodies against H. capsulatum and Coccidioides were not detected in the serum by either complement fixation or immunodiffusion. She was prescribed a six-week course of oral itraconazole. Upon further questioning, she reported having vacationed in Puerto Rico, an endemic region for histoplasmosis, within a year of her diagnosis. On that trip, she engaged in cave exploration.
Axial image from a CT scan of the chest set to lung window showing a solid 11mm nodule in the right lower lobe behind the diaphragm.