Renal Cell Carcinoma Metastasizing to the Cricoid Cartilage Presenting With Subglottic Stenosis: A Case Report and Literature Review.

A 72-year-old Japanese man with a 4-month history of hoarseness and 1-week history of difficulty breathing was admitted to our department. He underwent right total nephrectomy for primary clear cell-type renal cell carcinoma (RCC) 6 years ago and left partial nephrectomy for the metastasis 4 years ago. Flexible laryngeal fiberscope examination revealed bilateral subglottic stenosis without obvious mucosal lesions. Enhanced computerized tomography (CT) scan of the neck revealed that the cricoid cartilage had become bilaterally expansive and tumorous lesion exhibiting enhancement. We performed tracheostomy on the appointed day and biopsied the tumor in the cricoid cartilage via the skin incision. Results of histologic and immunohistologic examinations for AE1/AE3, CD10, and vimentin positivity were consistent with clear cell-type RCC. Chest and abdomen CT scans revealed a few tiny metastases in the upper lobe of the left lung but no recurrence in the abdomen. At 2 weeks from the day of tracheostomy, total laryngectomy was performed. Postoperatively, the patient was treated transorally with axitinib (10 mg/day) and as of 12 months he remains alive with unchanging lung metastasis. Next-generation sequencing of targeted regions using a surgical specimen from the tumor revealed a frameshift mutation in the von Hippel-Lindau gene (p.T124Hfs*35) and a missense mutation in the TP53 gene (p.H193R).