Clinical and Magnetic Resonance Imaging Longitudinal Follow-up of Neuromuscular Choristomas

Abstract

The natural history of growth and radiologic progression of neuromuscular choristomas (NMCs) remain unknown. The purpose of this study was to describe the radiologic growth pattern of NMCs and to determine how the pattern of growth relates to clinical progression. A retrospective review was performed for patients with a confirmed diagnosis of NMC and at least 2 years of radiologic (magnetic resonance imaging [MRI]) follow-up. Medical records, including physical examinations and radiologic studies, were reviewed in detail. The NMC length and transverse dimensions were compared between serial MRI examinations. Eleven patients with a mean radiologic follow-up time of 5.6 years (range 2-19 years) were identified. Motor deficits occurred in 10 patients (90%), sensory deficits in 5 patients (45%), and neuropathic pain in 4 (36%) patients. Eight patients (73%) presented with manifestations of limb undergrowth, 2 (18%) with congenital hip dysplasia, and 1 with a cavus foot deformity. Progression of motor and sensory deficits was observed in 5 (45%) and 1 (9%) patients, respectively. The maximal length and height of the NMC was significantly (P < 0.05) longer (initial 218 ± 118 mm vs. follow-up 270 ±135 mm) and larger (20 ± 10 mm vs. 24 ± 14 mm) on the follow-up scan. MRI demonstrated abnormalities that were in continuity along the longitudinal extent of the NMC. According to this small but relatively long-term follow-up cohort, the growth pattern of this lesion is slow but progressive. We found a longitudinal continuity pattern of growth in all MRI scans, often spanning a great distance.