Case Presentation: A 21-year-old female from the Ohio River Valley, previously healthy, presented in the winter for evaluation of a large lung mass of unknown etiology associated with cough, chest discomfort and shortness of breath. She initially presented to primary care for evaluation after 4 days of cough, dyspnea and malaise. Exposure history was notable for recent mold exposure in the home, otherwise no notable travel or other exposures. Vitals were stable and CXR was unremarkable. There was concern for pericarditis given presentation during the influenza season, so she was started on a course of indomethacin and colchicine. However, her symptoms remained persistent a week later, which led to a CXR which now revealed an abnormal density in the left upper lung. Chest CT then revealed a 7.1×3.9×2.7 cm mass-like consolidation with vascular encasement. She then presented to the hospital for further evaluation. On initial assessment, she was in stable condition without hypoxia. Initial workup revealed a CRP of 33.61, but otherwise normal range CBC, BMP, ESR, troponin, and procalcitonin. After discussion with infectious disease, pulmonary and thoracic surgery, we proceeded infectious testing and bronchoscopy with fine needle aspiration (FNA). We held empiric antibiotics given her clinical stability pending definitive diagnosis. Blood and sputum cultures were nonspecific, notably negative for tuberculosis (sputum, QuantiFERON Gold) and histoplasmosis (urine, serum Ab). FNA pathology revealed necrotizing granulomatous material with concern remaining highest for histoplasmosis infection. We discussed empiric treatment with itraconazole, but the patient opted to proceed with close follow up outpatient. On follow up with primary care 2 weeks, she reported persistent symptoms and was prescribed 6 weeks of itraconazole. Follow up imaging 4 weeks later revealed near resolution of the lung mass. Repeat lung imaging 6 months later revealed only a subcentimeter calcified granuloma. Final diagnosis was granulomatous reaction secondary to histoplasmosis pulmonary infection.
Discussion: Histoplasmosis is most common in the Mississippi and Ohio River valley regions, with lifetime exposure rates as high as 80-90%. Incidence is estimated to be 6.1 cases per 100,000 people. Immunocompetent patients are usually asymptomatic or have self limited disease, but patients with altered immune responses (e.g. HIV infection, organ transplant, steroid/TNF-inhibitor recipients) may have persistent and even develop disseminated infection with high mortality rates (i.e. 37% in untreated HIV). Up to 57% of immunocompetent patients may develop granulomas, though most are small. Patients should have close follow-up to monitor for persistent symptoms with consideration for repeat imaging as they may require antifungal treatment. Untreated infection can rarely lead to chronic disease or fibrosing mediastinitis.
Conclusions: Workup for pulmonary masses should include infectious causes such as tuberculosis and primary inflammatory causes such as sarcoidosis and malignancy. In addition, fungal etiologies should be considered, especially if an unclear cause after initial workup or features of patient history (travel, hobbies, place of residence) are present. Imaging characteristics can often help distinguish between these pathologies; however, a biopsy may be required for a definitive diagnosis.