Pulmonary cryptococcosis mimicking a metastasis in a patient with Ewing sarcoma.

Cryptococcosis is an invasive fungal infection that is common in immunocompromised patients. A 22-year-old woman with Ewing sarcoma in the right proximal humerus was treated by resection and chemotherapy. Computed tomography detected a small nodule in her right upper pulmonary lobe after completion of her chemotherapy. With the presumptive diagnosis of pulmonary metastasis, she underwent resection. Evaluation of the resected specimen revealed pulmonary cryptococcosis, and the patient was treated with oral fluconazole for 18 weeks. Extensive chemotherapy for high-grade sarcoma is a possible risk factor for pulmonary cryptococcosis. The differential diagnosis of a nodular pulmonary lesion that develops in a patient undergoing treatment for high-grade sarcoma is important.