Neurology Case Report: Rapidly Progressive Dementia and Extrapyramidal Symptoms as the First Presentation of Leptomeningeal Carcinomatosis

Leptomeningeal carcinomatosis (LC) is a rare complication of primary malignancy that spreads to leptomeninges and cerebrospinal fluid (CSF). Due to its rarity, it is often diagnosed as a late complication of an advanced tumor. This report presents a case study of a 72-year-old nonsmoking female with multiple comorbidities with two-week rapidly progressive cognitive decline and extrapyramidal symptoms (EPS). She presented with speech difficulties, tension headaches, and episodes of inattention. On examination, she had a masked face, mild bradykinesia, mild rigidity more apparent in the limbs than axially, and slight hyperreflexia in the lower limbs with a normal plantar reflex (down-going). Magnetic resonance imaging (MRI) of the brain with gadolinium showed diffuse leptomeningeal dissemination. CT of the right lower lobe showed lobe apical segment mass lesion with air bronchogram extension to the hilum, which raised the suspicion that the patient had lung cancer. The microscopic analysis of cerebrospinal fluid (CSF) cytology showed poorly differentiated malignant cells favoring adenocarcinoma. Based on these investigations, leptomeningeal dissemination on the MRI led to a wide differential diagnosis; however, given the findings in the CT scan and CSF, the patient was diagnosed with leptomeningeal carcinomatosis secondary to metastatic lung cancer. Although LC is a rare terminal complication that presents with a wide range of symptoms, typically including headache, altered mental status, diplopia, back pain, cerebral signs, and leg weakness, our patient presented with an uncommon presentation, which was EPS. Therefore, this case report highlights the importance of early detection of LC in any patient presenting with unspecific neurological manifestations.