Pulmonary Coinfection With C. Neoformans and C. Immitis Mimicking Malignancy

Abstract

INTRODUCTION: Cryptococcus neoformans and Coccidioides immitis are important opportunistic mycoses. C. neoformans is widely found in soil and bird droppings while C. immitis is endemic to the southwestern US. These infections behave more aggressively in immunocompromised hosts and may present as pulmonary nodules mimicking malignancy. We present a case of a pulmonary nodule revealing coinfection with both mycoses. CASE PRESENTATION:A 47-year-old male was brought to the ED due to erratic behavior. He was hemodynamically stable, but had choreoathetoid movements, lip smacking and garbled speech. He had a history of polysubstance abuse, baseline chorea of unknown etiology, and HIV not on ART. He was on vacation from California. Initial chemistries were normal. UDS was positive for amphetamines and methamphetamines. CT brain showed global cerebral atrophy. RPR was positive. Due to concern for CNS infection, LP was performed. Opening pressure and CSF studies were normal. MRI revealed global and caudate atrophy concerning for neurodegenerative disease. On hospital day 2, the patient was febrile to 102.7 degrees F with associated nonproductive cough. CXR revealed pneumonic consolidation in the LLL and a well-defined RLL nodule. Broad spectrum antibiotics were initiated. Chest CT confirmed a pleural based mass measuring 2.4x2.2 cm concerning for malignancy. CT guided lung biopsy revealed benign pulmonary parenchyma with extensive necrosis. GMS stain was positive for two morphologically distinct fungal species consistent with C. immitis and C. neoformans coinfection. Oral fluconazole was initiated with improvement in his clinical condition. His chorea and speech improved throughout his hospitalization. Underlying Huntington's disease exacerbated by amphetamine use was suspected.DISCUSSION: Pulmonary cryptococcosis is rare, representing 20% of pulmonary fungal infections. In immunocompetent hosts, it may present as a consolidation, reticulonodular process, or lung mass that mimics cancer. In those with altered immune function, it may establish latent infection through persistence within granulomas or may cause disseminated disease, such as meningitis. Similarly, C. immitis usually causes a severe pneumonia and may cause disseminated disease in immunocompromised patients. In non-immunocompromised patients, coccidiomycosis presents similarly to bacterial CAP with cough, fever and a consolidation on CXR (75%). However, thoracic manifestations are variable and include nodules, cavities, and peribronchial thickening. Pulmonary nodules caused by both fungal species may be positive on FDG-PET imaging, further mimicking malignancy. CONCLUSIONS: Our literature review returned no prior reports of pulmonary coinfection C. neoformans and C. immitis. We postulate that such a coinfection occurred due impaired host immune function and geographic prevalence of both organisms.