PD-1/PD-L1-negative tracheal mucoepidermoid carcinoma: A case report and systematic review of the literature

Background: Tracheal mucoepidermoid carcinoma is a rare form of non-small cell lung carcinoma and is defined as a tumor characterized by a combination of squamous, mucus-secreting, and intermediate cell types. This carcinoma is usually located in the lobar or segmental bronchus. Currently, surgery is the preferred treatment for this disease, which includes pneumonectomy, lobectomy, and sleeve lobectomy. Case presentation: A 50-year-old Chinese male presented with cough, shortness of breath and hemoptysis, and the effect of antibiotic therapy was not good. Subsequently, the airway occupied lesion was found by chest CT, and he was transferred to our hospital for surgical resection. Histologically, the tumor contained squamous epidermal cells, mucoepidermoid cells and intermediate cells. Immunohistochemistrically, the tumor cells were positive for p63, CK5/6, CK7 and Ki67. However, the tumor is generally negative for TTF-1 and neuroendocrine markers. The patient had no recurrence 15 months after the surgery. Conclusions: We report a rare case of mucoepidermoid carcinoma in the distal trachea in which the surgery was difficult and could not be performed like a traditional pulmonary resection. We first provide a comprehensive description of airway management and anesthesia intubation. After surgery, we reviewed the literature and found that PD-1/PD-L1 detection had never been reported in tracheal mucoepidermoid carcinoma. Therefore, we studied the PD-1/PD-L1 pathway in this patient, and the results were negative, which may indicate that potential adjuvant therapy with immune checkpoint inhibitors (ICIs) is not useful in this case.