The nearly invisible intraneural cyst: a new and emerging part of the spectrum

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>The authors have observed that a subset of patients referred for evaluation of peroneal neuropathy with “negative” findings on MRI of the knee have subtle evidence of a peroneal intraneural ganglion cyst on subsequent closer inspection. The objective of this study was to introduce the nearly invisible peroneal intraneural ganglion cyst and provide illustrative cases. The authors further wanted to identify clues to the presence of a nearly invisible cyst.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>Illustrative cases demonstrating nearly invisible peroneal intraneural ganglion cysts were retrospectively reviewed and are presented. Case history and physical examination, imaging, and intraoperative findings were reviewed for each case. The outcomes of interest were the size and configuration of peroneal intraneural ganglion cysts over time, relative to various interventions that were performed, and in relation to physical examination and electrodiagnostic findings.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>The authors present a series of cases that highlight the dynamic nature of peroneal intraneural ganglion cysts and introduce the nearly invisible cyst as a new and emerging part of the spectrum. The cases demonstrate changes in size and morphology over time of both the intraneural and extraneural compartments of these cysts. Despite “negative” MR imaging findings, nearly invisible cysts can be identified in a subset of patients.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>The authors demonstrate here that peroneal intraneural ganglion cysts ride a roller coaster of change in both size and morphology over time, and they describe the nearly invisible cyst as one end of the spectrum. They identified clues to the presence of a nearly invisible cyst, including deep peroneal predominant symptoms, fluctuating symptoms, denervation changes in the tibialis anterior muscle, and abnormalities of the superior tibiofibular joint, and they correlate the subtle imaging findings to the internal fascicular topography of the common peroneal nerve. The description of the nearly invisible cyst may allow for increased recognition of this pathological entity that occurs with a spectrum of findings.</jats:p></jats:sec>

Degenerative subtalar joints complicated by medial plantar intraneural cysts

“…4,[5][6][7][12][13][14] We speculate that failure to divide the jointganglion connection could be associated with a high rate of IGC recurrence. [2][3][4][9][10][11]15 The present study comprises an institutional series of IGCs involving the medial plantar nerve treated in various ways. The aim of the current study was to provide further support for the principles underlying the articular theory, and to explain the successes and failures of various treatment options.…”

A case of intraneural ganglion cyst of the peroneal nerve: A rapid recovery after incision of cyst

“…A relationship between degenerative changes, joint edema, and intraosseous ganglion cysts, an abnormal joint that may be at risk for capsular defects and cyst formation was reported. 9 In all cases with extra neural cysts, the nerve could be easily distinguished from the cyst. The extraneural cysts were more variable in shape compared to the intraneural ganglia, ranging in shape from oval to round with locations that could extend along fascial planes.…”

Intraneural ganglion cysts of the lower limb

“…Therefore, intraneural ganglion cysts occur at sites at which there is a nerve branch that supplies the joint and provides sensory information from the joint, in particular nociception and proprioception, to the central nervous system [4]. Intraneural ganglion cysts can be virtually invisible on MRI scans but still result in neuropathy in patients because the size and morphology of these cysts can vary [5]. However, the MRI method also has a decisive effect on the ability to visualize intraneural cysts.…”