Isolated Hypoglossal Nerve Palsy as an Initial Presentation of Metastatic Breast Cancer in Pregnancy: A Case Report

Isolated hypoglossal nerve palsy is rare, with neoplastic causes representing the most common etiology. We present an unusual case of metastatic breast cancer presenting with isolated hypoglossal nerve palsy during pregnancy. A 36-year-old primigravida at 17 weeks of gestation was admitted with progressive immobility, worsening back pain, and left-sided tongue deviation with hemi-atrophy. Laboratory investigations revealed hypercalcemia (corrected calcium 4.67 mmol/L) with suppressed parathyroid hormone levels. Imaging demonstrated skull base metastases involving the hypoglossal canal, hepatic metastases, and osseous metastases. Liver biopsy confirmed metastatic breast cancer (ER-positive, PR-positive, and HER2-negative). Following pregnancy termination, the patient commenced hormonal therapy with Goserelin and Anastrozole, with planned CDK4/6 inhibitor therapy. This case highlights the importance of considering metastatic disease in patients presenting with isolated cranial nerve palsies. The concurrent pregnancy created unique management challenges, requiring careful balance between maternal treatment needs and fetal considerations. Early recognition and multidisciplinary management are crucial for optimizing outcomes in such complex presentations.