Tumor-to-tumor metastasis: A case report of metastasis of nasopharyngeal carcinoma to meningioma and review of the literature.

RATIONALE: Tumor to tumor metastasis is a rare phenomenon clinically, especially tumor to meningioma metastasis. Here, we present an unusual case of metastasis of nasopharyngeal carcinoma to meningioma. PATIENT CONCERNS: A 55-year-old man, with a history of nasopharyngeal carcinoma, developed neurological symptoms. DIAGNOSIS: Computed tomography and magnetic resonance imaging revealed a mass on left temporoparietal lobe, indicating the presence of meningioma. The pathologist diagnosed the metastasis of nasopharyngeal carcinoma (differentiated non-keratinizing squamous cell carcinoma) to meningioma. INTERVENTIONS: Chemotherapy and immunotherapy were performed following the resection. OUTCOMES: The patient has been well and no relapses has been observed. LESSONS: Doctors should be aware of the presence of tumor-to-tumor metastasis, which is a rare phenomenon. A positive history of primary extracranial tumor should raise the suspicion of potential tumor-to-tumor metastasis.