Unusual case of long survival patient with leptomeningeal carcinomatosis from breast cancer.

Leptomeningeal carcinomatosis (LC) is defined as infiltration of the leptomeninges by metastatic carcinoma and often represents the end stage of cancer disease. In breast cancer, LC is associated with a median survival of approximately 6-8 weeks without specific treatment. It could increase by only few months with personalized treatment plans. Usually, the median time of onset of leptomeningeal spread is 18 months and it is diagnosed in up to 70% of patients with active and progressive systemic disease. We present an uncommon case of LC in a patient with history of breast cancer with a 10 year-disease-free condition and an overall survival after LC diagnosis of 10 months. Central Nervous System (CNS) Magnetic Resonance Imaging (MRI) showed contrast enhancement of medullary cone and cauda. Despite the negativity of cytological analysis of Cerebral-Spinal Fluid (CSF), the patient underwent meningeal and radicular biopsy in November 2019. The neuropathological examination confirmed the diagnosis of LC. The patient was started on the aromatase inhibitor anastrozole. A whole body contrast Computed Tomography (CT) scan at three months follow-up was negative for further disease dissemination. The patient is currently under oncological and radiological follow-up after more than 10 months from diagnosis. Although nowadays diagnosis of LC is prompted by cytological examination of CSF, its negativity should not halt the diagnostic process. In the presence of a high clinical suspicion of LC, we suggest the biopsy of lesion.