Leptomeningeal Carcinomatosis with Brain and Spinal Metastasis from Triple-negative Breast Cancer: A Case Report

Abstract

Leptomeningeal Carcinomatosis (LMC) is an uncommon but devastating complication of metastatic breast cancer, particularly associated with Triple-Negative Breast Cancer (TNBC). The authors report a 46-year-old female with previously treated TNBC and a parenchymal brain metastasis who presented with subacute, progressive bilateral lower-limb weakness and gait impairment. Contrast-Enhanced Magnetic Resonance Imaging (CE-MRI) of the brain and spine demonstrated diffuse leptomeningeal enhancement over the cerebellar hemispheres, spinal cord, and cauda equina, along with post-radiotherapy white-matter changes and hydrocephalus. Cerebrospinal Fluid (CSF) cytology confirmed the presence of malignant cells, establishing the diagnosis of LMC. Given her poor performance status and extensive intracranial and spinal disease burden, she was managed with palliative intent, including corticosteroids, analgesics, antiemetics, and best supportive care, but experienced progressive neurological decline. The present case highlights the close temporal relationship between brain metastases and LMC in TNBC, underscores the diagnostic value of CE-MRI with post-contrast Fluid Attenuated Inversion Recovery (FLAIR) and Three-Dimensional (3D) T1- weighted sequences combined with CSF cytology, and emphasises the need for heightened clinical suspicion and optimised palliative strategies in patients with advanced TNBC who develop new neurological symptoms.