A new case report describes a patient with Lambert-Eaton myasthenic syndrome (LEMS), small cell cervical cancer and breast cancer. This is the first report of a LEMS patient with two different cancers and underlines the importance of prompt diagnosis and treatment.
The case study, “Lambert-Eaton Myasthenic Syndrome Associated with Synchronous Double Cancer: A Combination of Small Cell Carcinoma of the Cervix and Breast Carcinoma,” appeared in the journal Internal Medicine.
LEMS is most commonly associated with small cell lung cancer, but rarely with gynecological and breast cancers.
The investigators from Shizuoka Cancer Center Hospital, in Japan, described the case of a 64-year-old who had a right mastectomy due to breast cancer. Further examination revealed that the patient had invasive lobular carcinoma, a type of breast cancer that starts in the milk-producing glands (lobules) of the breast.
Two months after mastectomy, she experienced general fatigue, leg weakness and a 10-kg weight loss. Fatigue in the arms and a dry mouth soon followed. A computed tomography (CT) scan showed an abnormal mass in the pelvis with multiple lymph node metastases.
Gynecological examination revealed a small cell cancer of the cervix, the opening between the uterus and the vagina. Small cell gynecological cancer is rare, representing less than 2% of all gynecologic malignancies, the authors wrote.
After lung cancer metastasis and recurrence of breast cancer were ruled out, the patient’s condition was attributed to the advanced state of the cervical tumor. She was treated for a month with local radiotherapy and chemotherapy, which was associated with a slight improvement of her unsteady gait. However, the leg weakness and susceptibility to fatigue persisted, with daily variation in their severity.
On a neurological examination to find other causes of the leg weakness — which at this stage had persisted for five months — she revealed normal arm strength and no signs of ptosis, or drooping eyelid, but her hip flexion and knee extension were weakened. Also, her deep tendon reflexes (nerve reflexes that determine muscle contraction upon tapping) were depressed.
Biochemical analysis showed low levels of the enzyme phosphate kinase, which, according to the researchers, suggested low possibility of myopathy, or muscle disease. Low potassium levels also were found.
Subsequent examination showed no alterations in the brain and spinal cord, but abnormal nerve conduction was seen. Higher-than-normal levels of anti-P/Q-type voltage-gated calcium channels antibody confirmed the diagnosis of LEMS.
Administration of Mestinon (pyridostigmine) enabled the patient to climb stairs without assistance and maintain her quality of life for five months. But despite the continuation of chemotherapy, bone and liver metastases developed. The patient died nearly a year after first showing symptoms of LEMS.
“Given these findings, we concluded that LEMS existed simultaneously with breast and small cell carcinoma of the cervix in this patient,” the scientists said. “To our knowledge, no other reports have described a case of LEMS associated with synchronous double cancer.”
They noted that this case report illustrates that neuromuscular disorders may be associated with a malignant tumor, LEMS should be considered when leg weakness is observed, gynecological and small cell lung cancer should be screened in LEMS patients, and accurate diagnosis and immediate treatment of such tumors are important.