Segmental rigidity and spinal myoclonus as a paraneoplastic syndrome.

A 68 year old woman is described with persisting muscular rigidity of the left lower leg together with transient myoclonic jerking in the left quadriceps muscle. Six weeks after onset a small cell carcinoma of the lung became manifest. With radiotherapy and chemotherapy complete remission was achieved. Segmental muscular spasm improved at the same time. Necropsy revealed loss and degeneration of alpha-motor neuron cells at one side of the anterior horn of the lumbar enlargement. This case may represent another manifestation of paraneoplastic subacute motor neuronopathy.