# Case report: Paraneoplastic lower motor neuronopathy associated with a malignant liver tumor

## TL;DR

A 71-year-old man with a liver tumor showed signs of a rare neurological condition, which improved after a combination of surgery and immunotherapy.

## Contribution

This case report highlights a rare association between a liver tumor and paraneoplastic lower motor neuronopathy, suggesting combined treatment approaches may be effective.

## Key findings

- A patient with a malignant liver tumor showed chronic progressive neuronal damage consistent with paraneoplastic lower motor neuronopathy.
- Treatment with hepatic artery chemoembolization, pembrolizumab, and lenvatinib led to clinical improvement.
- The presence of anti-Yo antibodies supported the diagnosis of a paraneoplastic syndrome.

## Abstract

Paraneoplastic lower motor neuronopathies (LMNs) have rarely been reported with malignant liver tumors. A 71-year-old man developed chronic progressive upper limb and cranial nerve paralysis. Electromyography examination suggests chronic progressive neuronal damage involving the right C4–T1 nerve root innervated muscle and the right sternocleidomastoid muscle. Magnetic resonance imaging suggested the presence of a malignant liver tumor. His serum was positive for anti-Yo antibodies. Hepatic artery chemoembolization was performed, followed by treatment with pembrolizumab and lenvatinib. The patient’s condition improved, and paraneoplastic LMNs were diagnosed. Paraneoplastic causes should be considered in the differential diagnosis of chronic progressive LMNs. A combination of surgical treatment and immunotherapy may result in a favorable outcome.