Ganglion of the posterior tibial nerve

Transcription

1 Case report MOSES STEPHEN MAHALEY, Jn., M.D., PH.D. Division of Neurosurgery and Department o] Anatomy, Duke University Medical Center, Durham, North Carolina A unique instance of ganglion of a posterior tibial nerve is described, and the histology and nature of this lesion evaluated. KEY WORDS ganglion schwannoma posterior tibial nerve intraneural cyst peripheral nerve G ANGLIA of peripheral nerves remain somewhat confusing entities with regard to both their etiology and pathological nature. They are not common peripheral nerve lesions, and when they occur certainly the most frequently reported location is the peroneal nerve. This case represents the first report of a ganglion discovered and removed from the posterior tibial nerve in the popliteal fossa. Case Report This 20-year-old male college student first came to Duke Hospital on October 7, 1971, because of the recent onset of pain in the posterior aspect of the left thigh and leg, unassociated with any back discomfort. The pain was exaggerated by exercise, particularly running. He was a left-footed punter and a wide-end receiver on the football team. First Examination. There was hypalgesia along the posterolateral aspect of the left leg below the knee, and straight-leg raising was positive at 60 ~ on the left. Popliteal compression on the left was positive. No specific treatment was advised at that time. He returned October 26, 1971, stating that in addition to the former complaints he had begun to notice parestbesias in the plantar aspect of the left foot during walking and particularly when punting. The findings were the same. Lumbosacral spine films revealed pars interarticularis defects of the fifth lumbar vertebra. He was admitted to Duke Hospital, where a lumbar myelogram was interpreted as normal. The cerebrospinal fluid protein was 18 mg%. It was felt that his symptoms were due to spinal nerve-root irritation. First Operation. The first sacral nerve root was explored on November 15, 1971; no ruptured disc was discovered, and a Gill procedure was performed to decompress the spinal canal posteriorly. Equivocal symptomatic improvement followed. Second and Third Examinations. The patient was seen again on February 28, 1972, for persistence of the original complaint. He gave no specific history of local knee trauma. The findings were unchanged. In October, 1972, he himself discovered a 120 J. Neurosurg. / Volume 40 / January, 1974

2 FIG. 1. Upper: Photomicrograph of a cross section of the cystic component of the posterior tibial nerve showing the relatively acellular structure with a few nerve fibers (arrows). H & E, X 512. Center." Myelinated nerve fibers (arrows) are seen. LFB-PAS, X 512. Lower." A few axis cylinders are identified (arrows). Bodian, X 512. mass in the left pop/flea/fossa. It was also becoming uncomfortable to sleep with the left leg straight because of paresthesias, which he could relieve by flexing the knee, and he described a transient episode of severe numbness in the sole of the foot lasting several minutes following one punting session. A sausage-shaped mass could now be felt in this region. Palpation of the mass produced paresthesias in the calf and plantar surface of the foot, and percussion produced paresthesias in the instep of the foot (Tinel's sign). Motor conduction velocity of the left posterior tibial nerve in January, 1973, was normal (42 m/sec), and electromyography revealed some denervation potentials in the gastrocnemius muscle. Second Operation. The popliteal fossa was explored on January 10, 1973, and a grossly enlarged posterior tibial nerve was discovered. The peroneal nerve was absolutely normal in appearance, as was the sciatic nerve above the origin of the posterior tibial nerve in the lower posterior thigh. The enlarged nerve showed no attachment of a bursa from nearby tendons or joint space. There was a single nerve branch that could be dissected off the posterior surface of the enlarged posterior tibial nerve, which provided innervation of the gastrocnemius muscle. The remainder of the posterior tibial nerve, along a length of 13 cm, was totally involved with a fusiform dilatation that measured 3 cm in diameter at its widest point. The enlarged nerve was opened in the hope that additional nerve bundles could be identified and spared. The nerve contained a considerable quantity of clear, reddish, gelatinoid material that could be milked out of the opening. The inner surface of the nerve was smooth and contained no nodules or irregularities. Nerve bundles could not be dissected away from the wail of the cyst. However, when the "tumorous" enlargement of the nerve was resected along its 13 cm length, it was found to narrow down to recognizable nerve bundles proximally and distally. Postoperative Course. The patient still has anesthesia of most of the plantar surface of the left foot and toes with paralysis of toe flexion and the posterior I. Neurosurg. / Volume 40 / January,

3 M. S. Mahaley, Jr. FIG. 2. Left: Histological longitudinal section of the same area shown in Fig. 1 revealing a single myelinated nerve fiber (arrows). LFB-PAS, X 810. Right: A single axis cylinder (arrows) is seen. Bodian, X 810. tibial muscle. He has resumed running and punting activities. Histological Examination. The nerve tissue was examined using hematoxylin and eosin (H & E), Bodian, Masson's, luxolfast-blue, and periodic acid-schiff (LFB- PAS) stains. It was composed primarily of a loosely arranged, relatively acellular area contained within a thickened epineurium, with a few identifiable nerve fibers within the substance of the tissue (Figs. 1 and 2). The cystic compartment was lined by mesothelial-like cells (Fig. 3). No evidence of neoplasia was seen. Discussion Although the earliest report of a ganglion of a peripheral nerve involved the median nerve, 8 the most common site has been the peroneal nerve. 2,4,n,7,9,11-14 Ganglia of the tibial nerve at the ankle, TM ulnar nerve, 5,7 and radial nerve 3 have also been described. In general, three types of ganglia have arisen: 1) a true ganglion, in the sense that the contents of the nerve communicate with an adjacent bursa or joint space, 2) pseudoganglion, in that the contents are mutinous and gelatinoid and are contained within a perineural or epineural sheath, and 3) a neoplastic process of neural origin 1 with degenerative changes leading to the production of semiliquid contents. In many of the cases reported, it was difficult to determine the relationship of the nerve fibers and the connective tissue components of the nerve to the "tumor" formation. The cases in which a communication was actually seen between the nerve enlargement and a nearby bursa or joint led authors to use the term "ganglion of the nerve" when referring to any of these three possible entities, particularly since each entity is most commonly located near a joint and contains material similar to that found in conventional joint or bursal ganglia. ]22 J. Neurosurg. / Volume 40 / January, 1974

4 uation of our case revealed no evidence of neoplasia and no hemosiderin deposits. Most of the involved nerve had been replaced by relatively acellular tissue which corresponded to the mucinoid material seen grossly at the time of surgery. This material was contained within what appeared to be a perineural compartment with a few residual nerve fibers present within the cystic structure. Both simple drainage of the nerve cyst contents and resection of the segment Of involved nerve have been advocated. Wadstein's TM report of recurrence in one case treated originally by subtotal excision has been cited as evidence favoring total excision. Complete excision was carried out in our case, because of our operative suspicion of a neoplastic change within the nerve. However, as an initial procedure in a functionally significant nerve, biopsy of the lesion and evacuation of the cyst would now seem preferable. FIG. 3. Photomicrograph showing mesothelial lining (arrows) of the cystic component of the posterior tibial nerve. H & E, X In the course of evaluating patients with unilateral leg pain and paresthesias, the possibility of a ganglion or intraneural cyst of a peripheral nerve must be considered. A past history of local trauma has been reported in approximately 25 % of the cases, and it is tempting to implicate this factor in our case in which the left knee was probably subjected to more than ordinary motion due to the punting and other football-related activities of the patient. Gurdjian, et al., 7 raised the possibility of an intraneural hemorrhage in one of the two cases they reported. However, the jelly-like contents characteristic of these lesions appear different from what one usually associates with an old hemorrhagic cavity, and the presence of hemosiderin within the lesion has not been a usual finding. Perhaps in cases like ours, in which no direct communication between the affected nerve and adjacent bursal or joint space is present, the term "intraneural cyst" should be used unless, of course, the process is clearly neoplastic. The histological eval- References 1. Abell MR, Hart WR, Olson JR: Tumors of the peripheral nervous system. Human Path 1: , Barrett R, Cramer F: Tumors of the peripheral nerves and so-called "ganglia" of the peroneal nerve. Clin Orthop 27: , Chodkow WN: Ganglien der peripherischen Nerven. Zhl Chit 53:680, Clark K: Ganglion of the lateral popliteal nerve. J Bone Jt Surg 43B: , Dubs J: Ganglion des Nervenscheide des Nervus Ulnaris. Deutsch Med Wochenschrift 48:68, Ferguson LK: Ganglion of the peroneal nerve. Ann Surg 106: , Gurdjian ES, Larsen RD, Lindner DW: Intraneural cyst of the peroneal and ulnar nerves. Report of two cases. J Neurosurg 23:76-78, Hartwell AS: Cystic tumor of median nerve; operation: restoration of function. Boston Med Surg J 144: , Katz MR, Lenobel MI: Intraneural ganglionic cyst of the peroneal nerve. Case report. J Neurosurg 32: , Loeffler F, Volkmann J: Ein seltener Befund bei angeblichen Plattfussbeschwerden (ganglion des Nervenscheide des Tibialis). Zbl Chir 47: , 1920 l l. Stack RE, Bianco AJ Jr, MacCarty CS: Compression of the common peroneal nerve,l Neurosurg. / Volume 40 / January, 1974 ]23

5 M. S. Mahaley, Jr. by ganglion cysts. J Bone.It Surg 47A: , Sultan C: Ganglion des Nervenscheide des Nervus peroneus. Zbl Chir 48: , Wadstein T: Two cases of ganglia in the sheath of the peroneal nerve. Aeta Orthop Seand 2: , Warren R: Ganglion of the common peroneal nerve: case report. Ann Surg 124: , 1946 Address reprint requests to: M. S. Mahaley, Jr., M.D., Ph.D., Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina ]2,4 J. Neurosurg. / Volume 40 / January, 1974