Successful treatment of advanced lung adenocarcinoma complicated with Lambert-Eaton myasthenic syndrome: A case report and literature review

Myasthenia-like paraneoplastic syndrome with multiple cranial nerve tumor infiltration: A case report and literature review

RATIONALE

Approximately 0.001% of patients with cancer have paraneoplastic nerve system syndrome, which can affect the central nervous system, neuromuscular junction, or peripheral nervous system. Although myasthenia gravis (MG) may exist as a thymic paraneoplastic syndrome (PNPS), its association with primary lung cancer remains unknown.

PATIENT CONCERNS

A 55-year-old female presented with slurred speech, weakness in chewing, sporadic difficulty in swallowing, and weakness in both lower limbs for half a year.

DIAGNOSES

Based on cerebrospinal fluid and electromyography findings, we present the case of a female patient diagnosed with overlapping multicranial nerve tumor infiltration and MG-like neurological PNPS secondary to lung adenocarcinoma.

INTERVENTIONS

The patient received intrathecal injections of pemetrexed and neurotrophic (vitamin B) therapy before ceasing chemoradiotherapy and chose cabozantinib on her own.

OUTCOMES

Weakness of the proximal limbs, choking cough, and chewing problems did not improve significantly.

LESSONS

Although it is unclear why MG coexists with lung cancer, it is probable that MG is a paraneoplastic condition. Cerebrospinal fluid testing should be carried out along with electrophysiological, serological, and pharmacological procedures pertinent to the diagnosis of MG to thoroughly examine if people simultaneously experience MG-like PNPS and tumor growth. Starting immunotherapy and anticancer medication at the same time that tumor development and MG-like syndrome are discovered is crucial.

Lambert-Eaton myasthenic syndrome revealed after surgery of lung adenocarcinoma

We report a very rare case of cT1N0M0 lung adenocarcinoma reveling Lambert-Eaton myasthenic syndrome (LEMS). A 69-year-old nonsmoking woman, with several comorbidities consulted for cough and dyspnea. Chest radiograph and CT scanning detected a left lower lobe mass; Needle biopsy confirmed differentiated adenocarcinoma; 18FDG-PET scan and Brain MRI eliminated metastatic disease dissemination. Our patient underwent a left lower lobectomy with mediastinal lymphadenectomy (pT1N0M0), no adjuvant chemotherapy was administrated. One month later patient present a muscle weakness in both lower limbs and fatigability followed by an inability to walk. The diagnosis of LEMS was made from the distinctive electromyogram (EMG) findings and a treatment with Amifampridine (3, 4-diaminopyridine phosphate [3, 4-DAP]) was prescribed with evident efficacy for symptoms.