In November 2019, a 50-year-old Chinese male was admitted to the hospital with intermittent cough and expectoration, which had lasted for more than one month. He was diagnosed as having a right renal tumor measuring 3.8 cm in diameter 16 years earlier, and he had undergone right radical nephrectomy. Postoperative pathological examination revealed Fuhrman grade II CCRCC (p T1a N0 M0). After surgery, he did not have a regular follow-up.
Physical examination and laboratory examination showed no significant findings. Thoracic contrast-enhanced computed tomography (CT) showed that a 40*35 mm mass was located in the posterior mediastinum, and it was clinically diagnosed as Castleman's disease ( Figure 1A ). Endobronchial ultrasonography showed that the posterior mediastinal mass was located far from the carina with a complete capsule, clear margin, and adequate blood supply ( Figures 1B, C ). However, other enlarged lymph nodes, local recurrence or distant metastases were not noted. Owing to the deep location and abundant vascularity of the mass, as well as the risk of bleeding, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) was not performed.
On November 21, 2019, the patient underwent video-assisted thoracoscopic surgery under general anesthesia. During the operation, the lesion was located under the carina with five abnormally large bronchial arteries ( Figures 1D, E ). No other swollen lymph nodes were observed. Fortunately, by gradually mobilizing the surrounding tissue of the mass and carefully ligating these bronchial arteries with the Hem-o-lok clips, the mass was completely removed ( Figure 1F ). Postoperative pathological examination indicated that the mass was a right mediastinal malignant tumor ( Figures 2A, B ). Immunohistochemical staining showed that the tumor cells were positive for cluster of differentiation 10 (CD10), vimentin, paired box 2 (PAX-2), paired box 8 (PAX-8), CK-Pan, and RCC markers but negative for cytokeratin 7 (CK 7), CgA, CD56, and synaptophysin (Syn) ( Figures 2C-H ). According to the patient's medical history and immunohistochemical findings, it was finally judged to be a metastasis from CCRCC. The patient had an uneventful postoperative recovery, and he underwent no further therapy after the operation. Currently, there is no clinical or radiological finding the recurrence of metastasis after 10 months of follow-up.