paravertebral ganglia hyperplasia overdevelopment or increased size, usually due to increased cell number, of the groups of postsynaptic neurons located at intervals along the sympathetic trunk, including the superior cervical, middle cervical and stellate (cervicothoracic) ganglia as well as the thoracic, lumbar and sacral ganglia MP:0001009 MPheno.ontology hyperplastic paravertebral ganglia abnormal paravertebral ganglion morphology