Lambert–Eaton myasthenic syndrome and prostatic adenocarcinoma

Excerpt

Lambert–Eaton myasthenic syndrome (LEMS) is characterized clinically by proximal muscle weakness, reduced or absent tendon reflexes and autonomic symptoms, combined with typical neurophysiological criteria or with the presence of pathogenic auto-antibodies to voltage-gated calcium channels (anti-VGCC) [1]. Typical neurophysiologic findings are low compound muscle action potentials (CMAPs) with decrement of more than 10 % at low-frequency repetitive nerve stimulation (RNS) and an increment of more than 100 % of CMAPs after maximum voluntary contraction or after high-frequency RNS. LEMS can be paraneoplastic or non-tumor related (NT-LEMS); in the former it is frequently associated with small cell lung cancer; however, combination with other malignancies should be considered. Prostate cancer has been reported as an extremely rare association with LEMS. In the four reported cases, three were small cell prostatic tumors [2‐4] (two of these had both neuroendocrine and small cell characteristics) and one was an adenocarcinoma [5]. We report a rare case of a patient with LEMS associated with prostatic adenocarcinoma, with clinical criteria and anti-VGCC positivity, but normal neurophysiological study. …