A collision tumor: Pituitary apoplexy caused by lung cancer metastasis

Abstract

A collision tumor refers to a rare phenomenon where two distinct neoplasms coexist occupying the same anatomical location. While metastatic brain tumors and pituitary adenoma are two of the most common intracranial tumors, the collision of the two tumors are extremely rare. We report a 76-year-old female patient with progressive visual field defect. She had a history of a stable pituitary adenoma and was recently diagnosed with lung adenocarcinoma with no known distant metastasis but with malignant pleural effusion. Her brain magnetic resonance imaging suggested a possible pituitary apoplexy with profound optic nerve compression. The patient underwent transsphenoidal surgery for tumor removal and the presence of metastatic cancer was confirmed by histopathological examination.