Amrami, Kimberly K.

The etiology of intraneural ganglion cysts has been poorly understood. This has resulted in the development of multiple surgical treatment strategies and a high recurrence rate. We sought to analyze these recurrences in order to provide a pathoanatomic explanation and staging classification for intraneural cyst recurrence. An expanded literature search was performed to identify frequencies and patterns in cases of intraneural ganglion cyst recurrences following primary surgery. Two univariate analyses were completed to identify associations between the type of revision surgery and repeat cyst recurrences. The expanded literature search found an 11% recurrence rate following primary surgery, including 64 recurrences following isolated cyst decompression (Group 1); six after articular branch resection (Group 2); and none following surgical procedures that addressed the joint (Group 3). Eight cases did not specify the type of primary surgery. In group 1, forty‐eight of the recurrences (75%) were in the parent nerve, three involved only the articular branch, and one travelled along the articular branch in a different distal direction without involving the main parent nerve. In group 2, only one case (17%) recurred/persisted within the parent nerve, one recurred within a persistent articular branch, and one formed within a persistent articular branch and travelled in a different distal direction. Intraneural recurrences most commonly occur following surgical procedures that only target the main parent nerve. We provide proven or theoretical explanations for all identified cases of intraneural recurrences for an occult or persistent articular branch pathway. Clin. Anat. 28:1058–1069, 2015. © 2015 Wiley Periodicals, Inc.

Based on our experience in treating peripheral non‐neural sheath derived pathology, we have identified a novel pattern of lesion progression along the anatomic course of nerves. This report highlights the existence of a subparaneurial compartment around peripheral nerves. We first applied an anatomic framework to review MR images and intraoperative photographs of patients treated by the senior author in the last 10 years. After identifying a pattern that was consistent with subparaneurial lesion progression, we searched for other examples of cases that might exhibit this pattern. Four examples of subparaneurial pathology were identified, a hemangioma of the ulnar nerve, a ganglion cyst of the common fibular nerve, a lymphoma of the sciatic nerve and a lipoma of the ulnar nerve. All four patients were operated on and had intraoperative photographs; three had high resolution MR imaging. This report highlights the existence of pathology contained within a subparaneurial compartment, outside of the epineurium, that follows the course of the nerve and surrounds it circumferentially. The subparaneurial localization of peripheral nerve lesions has hitherto received little attention. Identification of this new pattern on preoperative MRI may have implications for surgical management. Clin. Anat. 28:925–930, 2015. © 2015 Wiley Periodicals, Inc.

ABSTRACTIntroductionNeurolymphomatosis (NL) is a rare disorder characterized by invasion of cranial or peripheral nerves, nerve roots, or plexi, usually by aggressive subtypes of non‐Hodgkin lymphoma (NHL). The most common clinical presentation is that of a painful polyneuropathy or polyradiculopathy, followed by cranial neuropathy and, less frequently, by painless polyneuropathy.MethodsClinical and pathologic findings are reported for 2 NL cases.ResultsThe following 2 patients with NL, with disparate clinical presentations, are presented: a patient with subacute onset, painful, multifocal, mixed axonal and demyelinating radiculoplexus neuropathy due to a large B‐cell NHL, who required 2 targeted fascicular nerve biopsies to demonstrate NL; and a patient with a slowly progressive, length‐dependent axonal polyneuropathy due to a low‐grade B‐cell lymphoproliferative disorder, as shown on a diagnostic sural nerve biopsy.ConclusionsThe cases described illustrate the wide clinical spectrum of NL. Muscle Nerve 52:449–454, 2015

The authors describe the case of an intraneural ganglion cyst involving a cranial nerve (V3), which was found to have a joint connection in support of an articular origin within the cranial nerves. An inferior alveolar intraneural cyst was incidentally discovered on a plain radiograph prior to edentulation. It was resected from within the mandibular canal with no joint connection perceived at surgery. Histologically, the cyst was confirmed to be an intraneural ganglion cyst. Reinterpretation of the preoperative CT scan showed the cyst arising from the temporomandibular joint. This case is consistent with the articular (synovial) theory of intraneural ganglion cysts. An anatomical explanation and potential joint connection are provided for this case as well as several other cases of intraneural cysts in the literature, and thus unifying cranial nerve involvement with accepted concepts of intraneural ganglion cyst formation and propagation.

Perineural tumor spread in prostate cancer is emerging as a mechanism to explain select cases of neurological dysfunction and as a cause of morbidity and tumor recurrence. Perineural spread has been shown to extend from the prostate bed to the lumbosacral plexus and then distally to the sciatic nerve or proximally to the sacral and lumbar nerves and even intradurally. The authors present a case of a bilateral neoplastic lumbosacral plexopathy that can be explained anatomically as an extension of the same process: from one lumbosacral plexus to the contralateral one utilizing the dural sac as a bridge between the opposite sacral nerve roots. Their theory is supported by sequential progression of symptoms and findings on clinical examinations as well as high-resolution imaging (MRI and PET/CT scans). The neoplastic nature of the process was confirmed by a sciatic nerve fascicular biopsy. The authors believe that transmedian dural spread allows continuity of a neoplastic process from one side of the body to the other.