Pulmonary cryptococcosis coexisting with central type lung cancer in an immuocompetent patient: a case report and literature review

Abstract

Background: Pulmonary Cryptococcosis is a common fungal infection mainly caused by Cryptococcus neoformans/C.gattii species in immunocompromised patients. Cases of pulmonary cryptococcosis in patients with normal immune function are increasingly common in China. Clinical and radiographic features of pulmonary cryptococcosis are various and without obvious characteristics, so it is often misdiagnosed as pulmonary metastatic tumor or tuberculosis. When coexisting with malignant lung tumors, it was more difficult to differentiate from metastatic lung cancer, although the coexistence of pulmonary cryptococcosis and central type lung cancer is rare. Reviewing the imaging manifestations and diagnosis of the case and the relevant literature will contribute to recognition of the disease and a decrease in misdiagnoses.

Case presentation: A 72-year-old immunocompetent Han Chinese man had repeated dry cough for more than half a year. CT examination of chest showed an irregular mass at the left hilum of the lung, and two small nodules in the right lung, which were considered as the left central lung cancer with right lung metastasis. However, the patient was diagnosed with pulmonary cryptococcosis coexisting with central type lung cancer based on the results of laboratory examination, percutaneous lung biopsy, fiberoptic bronchoscopy, and surgical pathology. The patient underwent surgical resection of the left central type lung cancer and was placed on fluconazole treatment after a positive diagnosis was made. Five years after the lung cancer surgery, the patient had a recurrence, but the pulmonary cryptococcus nodule disappeared.

Conclusion: Our case shows that CT findings of central type lung cancer with multiple pulmonary nodules are not necessarily metastases, but may be coexisting pulmonary cryptococcosis. CT images of cryptococcosis of the lung were diverse and have no obvious characteristics, so it was very difficult to distinguish from metastatic tumors. CT-guided percutaneous lung biopsy was a simple and efficient method for identification.

Keywords: CT-guided percutaneous lung biopsy; Central type lung cancer; Computed tomography; Cryptococcosis; Metastatic tumor; PAS periodic acid-Schiff.

Fig. 1

a axial lung window and b axial mediastinal window showed an irregular mass of about 4 × 3 cm(black arrow), near the hilum of the left lung, with unclear boundary, fine burrs and shallow lobes. Left upper lobe bronchial stenosis, distal obstruction, and a few small segmental patchy shadows were seen in the distal upper lobe of the left lung

Fig. 2

a showed a1.0 × 0.8 cm nodule (black arrow) in the subpleural area of the posterior segment of the upper lobe of the right lung, with unclear boundaries, no obvious lobulation or burr signs, and no calcification. b showed a 1.2 × 0.9 cm nodule (black arrow) in the subpleural region of the dorsal segment of the right lower lobe, with lobular depression and adjacent vascular aggregation, but no obvious thickening

Fig. 3

The chest CT showed that two corresponding nodules in the original right lung had disappeared after 4 years later

Fig. 4

a: Puncture biopsy of nodules in the dorsal segment of the right lower lobe in prone position. b: Puncture tissue, microscopic alveolar cavity and alveolar septum see multiple nuclear giant cells and epithelioid cells vacuoles or small round body. c: PAS (+) The red arrows indicate some of the round bodies of cryptococcus after PAS staining; d: PASM (+)

Fig. 5

a/b:(Left upper) Pulmonary lobectomy: 1.Moderately-poorly differentiated squamous cell carcinoma, with carcinomatous nodule formation. 2.Cryptococus infection. b: It showed polynuclear giant cells and epithelioid cells in the alveolar cavity and alveolar septum as well as vacuoles or round bodies inside