Pituitary Metastatic Composite Tumors: A Case Report withNext-Generation Sequencing and Review of the Literature

While pituitary tumors are well understood, little research has been done on metastasis from primary tumors intopituitary adenomas, also known as composite tumors. Because only 34 cases of composite tumors have been reported to date,we hope to better characterize these tumors by reviewing cases reported in the literature and reviewed our own documentedcase, which includes next-generation sequencing.Case Presentation. A 74-year-old man presented to the emergency departmentwith left vision loss for 3 months. He had a history of colon cancer treated with colectomy and clear cell renal carcinoma treatedwith left nephrectomy. A preoperative MRI demonstrated growth of a peripherally enhancing, centrally necrotic mass with sellarexpansion measuring5:7×3:1×3:0cm. Given thesefindings, an endoscopic endonasal transsphenoidal resection wasperformed. Histological assessment revealed a composite tumor: one neoplasm was a nonfunctioning pituitary adenoma, andanother neoplasm was a clear cell carcinoma. Next-generation sequencing demonstrated that the tumors shared mutations inVHLandNotch2. The patient died 2 months later from systemic metastatic cancer.Conclusion. From our literature review, mostmetastatic lesions in these composite tumors originated from neoplasms of the lung and kidney. Approximately 63% patientspresented with ophthalmoplegia as the initial symptom while 23% displayed hormonal abnormalities. Postoperative mortalityhad a median of 3.5 months. In our patient, the presence ofVHLandNotch2 mutations in both tumors highlights thepossibility of using next-generation sequencing to help identify therapeutic targets even in complex composite neoplasms