Because of the peripheral location of the CCTL in most cases, transbronchial biopsy is not an option. CT scan-guided fine needle aspiration in most cases is the feasible option, but because CCTLs are rich in thin-walled sinusoidal vessels, there remains a theoretical risk of massive hemorrhage associated with the procedure, although none has been documented in the reported cases. With biopsy, it is easy to diagnose a CCTL based on its characteristic histologic appearance and immunohistochemical characteristics. The high glycogen content of the cells makes Periodic acid-Schiff (PAS) staining an essential step in the diagnosis. The tumor stains positive with PAS, and after diastase treatment, appears negative. The main immunohistochemical characteristics of CCTL are human melanoma black (HMB)-45 positivity, S-100 positivity, vimentin positivity, and cytokeratin negativity. Immunoreactivity for HMB-45 delineates perivascular epitheloid cell differentiation, and vimentin indicates the mesenchymal origin of tumor cells. In a study of CCTLs, Bingqiang et al reported HMB-45 positivity in 19 of 21 cases; S-100 positivity in 17 of 20 cases; vimentin positivity in 16 cases; neuron-specific enolase positivity in seven of 20 cases; and no reactivity to cytokeratin, epithelial membrane antigen, and chromogranin.