Early Treatment Key in Rare LEMS Case Linked to Tumor in Larynx

The case of a man in whom a neuroendocrine tumor was found to be associated with Lambert-Eaton myasthenic syndrome (LEMS) underscores the importance of early diagnosis and treatment of the two rarely associated conditions.

“To the best of our knowledge, this current case has only one similar precedent in the published literature and it is the second report of an association between a [neuroendocrine tumor] and LEMS,” the researchers wrote.

The case was described in a study, “Neuroendocrine carcinoma of the larynx with Lambert-Eaton myasthenic syndrome: a rare case report and literature review,” published in the Journal of International Medical Research.

LEMS is an autoimmune disease that targets the nerves that control muscle movement. Although it can occur spontaneously, LEMS is frequently associated with cancer. Autoimmune diseases like LEMS that can be triggered by the body’s immune response against cancer are called paraneoplastic syndromes (PNS). 

Rare are cases that link neuroendocrine cancer, which affects the neuroendocrine cells that release hormones in response to nerve signals, to PNS. Only 10 cases of PNS associated with neuroendocrine cancer of the larynx have been reported, one of which involved LEMS. 

This report describes the case of a 68-year-old man who had LEMS related to neuroendocrine cancer of the larynx, making it the second such reported case in the literature, according to the researchers.

The patient was hospitalized with difficulty speaking and swallowing, which had persisted for the previous three months. He had difficulties managing his personal care, and a history of overall tiredness and lack of energy, along with dry mouth, constipation, and urinary retention. 

A computed tomography scan detected a large growth on the left wall of his larynx, which a biopsy later revealed to be a poorly differentiated carcinoma with signs of neuroendocrine cell growth, indicative of poorly differentiated neuroendocrine cancer. 

Based on his medical history, physicians suspected the patient had neuroendocrine cancer associated with LEMS. The patient then underwent a total laryngectomy, or surgical removal of the larynx.  

A tissue analysis performed after surgery confirmed the diagnosis of poorly differentiated carcinoma and revealed the presence of nine neck lymph nodes with cancerous growth. At this point, three cycles of chemotherapy with cisplatin-etoposide were initiated, followed by radiotherapy. 

The patient started showing clear signs of improvement a month after surgery. By three months post-surgery, the patient was walking without any orthopedic aids, and his dry mouth and gastrointestinal and urinary symptoms had resolved. The patient remained well and disease-free three years after surgery.

“Neuroendocrine carcinomas of the larynx are rare lesions with different prognostic characteristics. PNS can rarely accompany the [tumor] and therefore be useful in monitoring its evolution,” the researchers wrote.

“An early diagnosis of a PNS and its treatment can have positive effects on the general clinical outcome, with more appropriate direct therapy on the tumour and an improvement in quality of life,” they concluded.