Pulmonary Cryptococcosis in an Immunocompetent Patient: Negative mNGS but Positive Antigen Test

BACKGROUND: Pulmonary cryptococcosis is common in patients with immunodeficiency, application of immunosuppressive and cytotoxic drugs. Its incidence has increased in recent years, with a greater number of patients with no underlying disease or history of exposure, and a greater number of immunocompetent patients. Its clinical presentation lacks specificity and imaging features are atypical, making it easy to misdiagnose or miss the diagnosis. METHODS: Diagnosis was confirmed by serum cryptococcal antigen after negative bronchoalveolar lavage fluid mNGS in an immunocompetent patient with atypical radiological findings. RESULTS: We present a 53-year-old female patient with pulmonary cryptococcosis who was immunocompetent, had atypical imaging, and was diagnosed by a negative bronchoalveolar lavage fluid mNGS test and confirmed by cryptococcal pod antigen test. CONCLUSIONS: By analyzing and discussing the diagnosis and treatment process of the patient with cryptococcosis, we aim to strengthen clinicians' knowledge and diagnosis and treatment ability of pulmonary cryptococcosis in order to improve the early diagnosis and treatment rate of this disease and reduce misdiagnosis or omission.