A Rare Intracranial Collision Tumor of Meningioma and Metastatic Uterine Adenocarcinoma: Case Report and Literature Review

BACKGROUND: A collision tumor is a rare entity consisting of 2 histologically distinct tumor types (benign or malignant) in the same anatomic location. This can occur from a tumor-to-tumor metastasis or as a result of 2 adjacent intracranial tumors colliding and growing together. To our knowledge, this is the first reported case of collision tumor with confirmed meningioma and uterine adenocarcinoma. Multiple mechanisms have been proposed for the facilitative growth of collision tumors, including local epigenetic signaling. Clinically, it is important to consider collision tumors in the differential diagnosis of a rapidly growing intracranial lesion in the setting of systemic cancer to provide optimal surgical and postoperative management. CASE DESCRIPTION: A 78-year-old, right-handed woman with a known 10-year history of stable meningioma presented for evaluation of a right sphenoid wing lesion. She had recently completed treatment of uterine papillary serous carcinoma with no evidence of disease on follow-up imaging. On presentation, there was significant progression of the meningioma resulting in brain compression and right third nerve palsy. The patient underwent urgent resection of the lesion. Pathology demonstrated a collision tumor with a combination of metastatic uterine papillary serous carcinoma and meningioma. CONCLUSIONS: It is important to consider a collision tumor when a patient with a benign intracranial lesion presents with rapid progression, even in the context of a systemic cancer that rarely metastasizes to the brain. Appropriate histopathologic assessment is crucial in these cases and can have a significant impact on treatment plan and prognosis.