Intraneural Cyst of the Peroneal and Ulnar Nerves

Abstract

Intraneural cyst is a rare lesion. Probably the earliest case was that of Hartwell 4 reported in 1901. The patient had a mass the size of a chestnut on the medial aspect of the arm just above the elbow and at operation it was found to be a cystic tumor involving the median nerve. The contents of such a cyst may be semigelatinous in consistency and result from mucoid degeneration of a schwannoma or a neurilemmoma. An intraneural cyst should not be mistaken for a ganglion which may by proximity cause compression of an adjacent nerve. At times, a connection between a cystic mass and the joint has been found in the vicinity of a nerve traversing a joint such as the knee, suggesting the possibility of synovial origin. The possibility of traumatic origin of an intraneural cyst has been discussed by Brooks3 It is felt that one of our cases (Case 1) represents posttraumatic cystic degeneration involving the peroneal nerve while the second case is more truly one of mucoid degeneration within the substance of the nerve. In neither of our cases was there a wellformed lining, and on neurolysis the semigelatinous material extruded, leaving behind a space surrounded by the bundles of nerve. There were no unusual extensions of the cystic cavity superiorly or inferiorly. Recently, Barrett and Cramer 1 reported on 4 cases of this condition involving the common peroneal nerve. Later, Cramer 3 discussed his experiences with this disease before the Harvey Cushing Society in April, 1964. These authors emphasized the importance of careful dissection during removal of the cysts and suggested that only simple decompression be done when the integrity of the nerve is threatened. They feel that in nonoperative cases distal degeneration of the nerve fibers will occur. The ~ patients reported upon in this paper were seen within l0 days of each other at the Grace Hospital. Case 1 was operated upon in the Department of Neurosurgery and Case 2 was treated in the Department of Hand Surgery.

Case Report: Intraneural Ganglion Cyst of the Ulnar Nerve at the Wrist

“…In our literature review of upper extremity intraneural ganglions, we have found that the time from symptomatic presentation to surgery for complete to nearcomplete recovery ranged from as little as 4 weeks to more than 1 year [1,4,8,10,13,15]. Incomplete or moderate recovery was found in patients symptomatic for 8 months and 2 years [1,5]. In the two cases of little to no recovery after complete excision, one patient was symptomatic for only 2 months [1] and the other for 6 months [2].…”

“…All of the cited reports of intraneural ganglion of the ulnar nerve at the level of the wrist [1,5,9,10,15] involved the deep branch of the ulnar nerve. Our presented case involved a similar ganglion, found in the deep motor branch of the ulnar nerve, just below the level of the hypothenar muscles.…”

Ulnar Nerve Compression in the Cubital Tunnel by an Epineural Ganglion: A Case Report

“…[3, 5-16, 18, 20-24, 26, 1, 2, 17] Since the first description of ganglia involving nerves, [8] most reported cases concern the common peroneal nerve at the head of the fibula. [6,15,16,18,22,23,26] The compression of the ulnar nerve in the cubital tunnel by a ganglion is not common. [5,10] In addition, most ganglion cysts involving nerves originate from the adjacent joints.…”

Intraneural ganglia: a clinical problem deserving a mechanistic explanation and model

“…The capsular defect may be preexisting and is likely the result of a traumatic, degenerative, or congenital process. 11,44,45 In the peroneal intraneural ganglia model, evidence suggests that direct or indirect cumulative trauma 13,14,20,44 to the superior tibiofibular joint itself or in relation to the neighboring (and often communicating) knee joint is important in the development of the cysts. 45 Increased intraarticular pressure (that is, static or dynamic) is the other mechanism involved at the jointjoint capsule interface.…”

“…Different theories, without a scientific basis, have been proposed. 4,[6][7][8]15,19,20,24,27 The articular (synovial) theory, 42,45 based on robust clinical, imaging, and histological evidence, 11,[39][40][41][42]44,45,47,49,50 provides a logical, consistent explanation that clarifies and unifies the observations made by many over the years. Developed on the prototype of the peroneal nerve ganglion cysts, the theory can be extrapolated to intraneural ganglion cysts involving other nerves.…”