Metastatic Seeding From a Gastrointestinal Neoplasia in a Pituitary Adenoma: A Case Report and Literature Review.

Pituitary composite tumors consisting of metastasis within an adenoma are rare and aggressive entities. We present a case of esophageal adenocarcinoma metastasis at a prolactinoma presenting in a unique fashion and highlight how this case could contribute to a better understanding and early recognition of this condition. The patient was a 65-year-old male who presented with partial palsy of the third and sixth cranial nerves. He had a history of treated esophageal adenocarcinoma. He also had a known small parasellar lesion, with an elevated prolactin. Investigations showed a rapid progression of the parasellar lesion and normalization of prolactin. Partial surgical resection was performed, and pathology confirmed metastasis of the known digestive tract neoplasia. Although extremely rare, dual pathology of pituitary metastasis within adenomas should be considered in the differential diagnosis of sellar masses. Atypical behavior of benign adenomas, including rapid growth, spontaneous normalization of prolactin, or progression despite medical treatment should prompt medical teams to reconsider their diagnosis.