INTRODUCTION:Little has been published on endobronchial histoplasmosis. We report a case of endobronchial and progressive disseminated histoplasmosis mimicking metastatic carcinoma.
CASE PRESENTATION:A 47 year old white male with a 45 pack year history presented to his primary care physician with a 50 pound weight loss, chronic cough productive of white sputum, and persistent mouth ulcers over a 3 month period. Physical exam was significant for mild cachexia and oral apthous ulcers. Work-up revealed mildly elevated transaminases and a right upper lobe (RUL) mass on chest radiograph (CXR). Computed tomography (CT) of the chest revealed bilateral adrenal masses in addition to the lung mass. CT guided biopsy of the RUL mass was nondiagnostic. A subsequent adrenal biopsy demonstrated necrotic tissue and a few yeast forms morphologically suggestive of Candida species. He was then referred to otolaryngology; biopsies of ulcerations in the left arytenoid and anterior subglottic region revealed ulcers with acute and chronic inflammation, reactive atypia, and yeast-like organisms. He was referred to the oncology clinic with the presumptive diagnosis of metastatic cancer. Further CT imaging revealed numerous small enhancing cortical brain lesions and a left mainstem (LMSB) endobronchial mass in addition to the previously noted abnormalities. He was eventually referred to the pulmonary clinic where the diagnosis of a disseminated fungal infection was entertained. A urinary antigen for Histoplasmosis capsulatum (H. capsulatum), HIV test, and sputum culture were negative. Diagnostic bronchoscopy revealed numerous polypoid lesions lining both the trachea and bilateral mainstem bronchi that were of variable size from several millimeters to greater than a centimeter in diameter. They were smooth without visible vessels or ulceration. Endobronchial biopsy and bronchoalveolar lavage were performed demonstrating reactive bronchial epithelial cells and alveolar macrophages with engulfed yeast forms consistent with H. capsulatum (confirmed by culture). He was treated with 10 days of amphotericin and then oral itraconazole. Over the next 6 months, all lesions regressed, his energy returned, and he gained 25 pounds.
DISCUSSIONS:H. Capsulatum is a dimorphic fungus endemic to parts of the United States. Every year hundreds of thousands of people are infected. Inhalation of the organisms is the primary mode of infection, leading to yeast form transformation and systemic dissemination. The yeast forms are typically small (2-4 μm), uninucleated, with single narrow-based buds. They must be distinguished from other fungi, including Candida and Pneumocystis species. The extent of disease is dependent of the number of organisms inhaled and the immune response of the host. Most infected patients remain asymptomatic or develop a self-limited disease. Acute progressive disseminated histoplasmosis (PDH) is most often seen with a large inoculum or in the setting of a T-lymphocyte mediated immunosuppression. Conversely, chronic PDH is seen almost exclusively in otherwise healthy adults. Low grade fever, malaise, and oropharyngeal ulcers are common. CXR may reveal patchy infiltrates in one or more lobes with associated lymphadenopathy. Endobronchial histoplasmosis is rare. A recent review identified only 11 cases in the literature, none to this extent and none in the setting of chronic PDH. As noted in a case series from Ohio State University, these lesions may masquerade as a primary endobronchial neoplasm.
CONCLUSION:We describe a case of chronic PDH associated with lesions involving the tracheobronchial tree, pulmonary parenchyma, oral mucosa, adrenal glands, and brain. Given his smoking history, weight loss, and lack of infectious symptoms, it was presumed that his illness represented metastatic lung cancer. While this case is an extremely unusual presentation, it illustrates the importance of considering disseminated fungal disease in the differential diagnosis of endobronchial lesions and apparent metastatic disease, the need for tissue diagnosis, and the importance of alerting the pathologist to these concerns.
DISCLOSURE:Nicole Gray, No Financial Disclosure Information; No Product/Research Disclosure Information