Coccidioides immitis (Cocci) is endemic to the soils of the Southwestern United States and commonly presents as community-acquired pneumonia. Bony lesions are uncommon even in disseminated infection and cranial involvement can be associated with significant morbidity. A case report being presented at Chest 2021 looks at a particular case where the imaging pattern and clinical presentation was concerning for metastatic lung cancer but turned out to be disseminated cocci.

In the case presentation, a 58-year-old woman with a history of diabetes presented with headaches for 4 weeks. She did not have pulmonary symptoms or meningeal signs on presentation. Head MRI was notable for multiple osseous lesions of the skull and a single left temporal lobe lesion. The imaging pattern was concerning for metastasis, as chest CT revealed a 7.7 cm mass with central cavitation in the right lower lobe with multiple pulmonary nodules. Bronchoscopy with transbronchial biopsy showed cocci spherules with giant cell granulomas. Cocci IgM and IgG serology were positive.

Cerebrospinal fluid showed elevated lymphocytes and protein, raising concern for cocci meningitis. Fluconazole, 600 mg and twice daily, was started. Interval chest CT showed the right lung mass had decreased in size, however brain MRI showed worsening meningeal enhancement with multiple ring-enhancing lesions along the basal cisterns, proximal left sylvian fissure and temporal lobe. The patient, however, had no neurological signs or symptoms on follow-up. Neurosurgical intervention was not recommended, and fluconazole was continued outpatient with a plan for follow-up imaging.

The extrapulmonary manifestation of cocci raised concern for malignancy. The patient presented with primarily neurological symptoms of headache with imaging suspicious for bone metastasis from a lung mass. Neurological cocci remains difficult to treat. Since the patient was free from neurological symptoms, a decision was made after consultation with infectious diseases and neurosurgery to avoid invasive procedures and allow more time for antifungal treatment. This case highlights the radiographic similarity between disseminated Cocci and metastatic cancer and the importance of invasive investigation to make a definitive diagnosis and initiate appropriate treatment.

“Disseminated coccidioidomycosis may have varied clinical presentations, including mimicking cancer, and should be on a differential for pulmonary or mediastinal masses with invasive investigations radically changing management and prognosis,” said Sharjeel Israr, MD, lead researcher and Chest 2021 presenter.