Intraneural ganglia in the hip and pelvic region. Clinical article.
OBJECTIVE
The authors describe their experience in a series of cases of intraneural ganglia within the hip and pelvic regions, and explain the mechanism of formation and propagation of this pathological entity.


METHODS
Five patients with 6 intraneural ganglia are presented. Four patients presented with symptomatic intraneural ganglia in the buttock and pelvis affecting the sciatic and lumbosacral plexus elements. An asymptomatic cyst affecting the opposite sciatic nerve was found on MR imaging in 1 patient. The fifth patient, previously reported on by another group, had an obturator intraneural ganglion that the authors reinterpreted.


RESULTS
All 5 intraneural ganglia affecting the sciatic and lumbosacral plexus elements were found to have a joint connection to the posteromedial aspect of the hip joint; the obturator intraneural cyst had a joint connection to the anteromedial aspect of the hip joint. In all cases, initial review of the MR images led to their misinterpretation.


CONCLUSIONS
To the authors' knowledge, these are the first cases of intraneural ganglia demonstrated to have a connection to the hip joint. This finding at a rare site provides further evidence for the unifying articular (synovial) theory for the formation of intraneural ganglia and reveals a shared mechanism for their propagation. Furthermore, understanding the pathogenesis of these lesions provides insight into their successful treatment and their recurrence.
Spinner
Robert J
RJ
Department of Neurosurgery, 200 First Street SW, Mayo Clinic Rochester, Minnesota 55905, USA. spinner.robert@mayo.edu
Hébert-Blouin
Marie-Noëlle
MN
Trousdale
Robert T
RT
Midha
Rajiv
R
Russell
Stephen M
SM
Yamauchi
Tatsuya
T
Sasaki
Syouzou
S
Amrami
Kimberly K
KK
D000328:Adult; D002081:Buttocks; D005260:Female; D045888:Ganglion Cysts / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D006621:Hip Joint; D006801:Humans; D008160:Lumbosacral Plexus / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010388:Pelvis; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D012584:Sciatic Nerve / Q000473:pathology