Lung adenocarcinoma concurrent with pulmonary cryptococcosis: a case report and literature review

Pulmonary cryptococcosis (PC) is a common opportunistic fungal infection caused by Cryptococcus neoformans or Cryptococcus gattii. PC primarily invades the respiratory system, followed by the central nervous system. Few clinical reports have examined the coexistence of PC and lung cancer. This study reports the case of a 54-year-old immunocompetent PC patient with lung adenocarcinoma. Chest CT revealed multiple nodules in the right lung, with the largest nodule located in the dorsal segment of the right lower lobe. 18 F‑FDG positron emission tomography-computed tomography (PET-CT) revealed elevated glucose metabolism in the dorsal segment of the right lower lobe, which suggested lung cancer. The metabolism level of the nodule in the basal segment of the right lower lobe and the anterior segment of the right upper lobe was not abnormally increased, but the possibility of a malignant tumour could not be excluded. The pulmonary nodules in the dorsal segment and the basal segment of the right lower lobe were simultaneously resected via video-assisted thoracic surgery (VATS), and the final histopathology revealed primary lung adenocarcinoma and pulmonary cryptococcal infection, respectively. After surgery, antifungal treatment was administered for 3 months. Over the 3-year follow-up, contrast-enhanced computed tomography (CT) revealed no recurrence of either disease. This case study highlights the possibility of dualism in the diagnosis of multiple pulmonary nodules on chest CT, such as the coexistence of lung cancer and PC. Surgical resection is recommended for micronodules that are not easy to diagnose via needle biopsy; in addition, early diagnosis and treatment are helpful for ensuring a good prognosis. This paper reports the clinical diagnosis and treatment of one patient with pulmonary cryptococcal infection of the right lung complicated with lung adenocarcinoma, including 3 years of follow-up, providing a reference for clinical practice.