Recurrent intraneural ganglion cysts: Pathoanatomic patterns and treatment implications

Cubital Tunnel Syndrome Due to Intraneural Ganglion Cysts of the Ulnar Nerve With Joint-Cyst Connection at the Elbow

BACKGROUND AND OBJECTIVES

The unifying articular theory suggests that intraneural ganglion cysts in the cubital tunnel arise from the elbow joint and are connected to the ulnar nerve through an articular branch. This study aimed to report our clinical experience with these cysts and our surgical findings and outcomes.

METHODS

We retrospectively analyzed 13 patients who underwent surgery for cubital tunnel syndrome caused by an intraneural ganglion cyst of the ulnar nerve. Clinical symptoms, physical examination findings, nerve conduction testing electromyography, plain radiography, and ultrasonography were evaluated before and after surgery. MRI was performed in 2 patients. Cyst decompression, disconnection of the articular branch, and ulnar nerve transposition were performed in all.

RESULTS

The mean follow-up was 29 months. After surgery, local elbow pain and Tinel sign disappeared in all patients, and the average Numerical Rating Scale dropped from 3.7 (2-5) to 0 (0-0). Two-point discrimination testing was normal (<5.0 mm) in 12 patients. Wartenberg sign and "claw hand" deformity became negative, and muscle function and motor nerve conduction velocity were improved in 12 patients. The Medical Research Council muscle strength grade was M4 or M5 in the flexor carpi ulnaris, flexor digitorum profundus of the 4th and 5th digits, and first dorsal interosseous muscle in 12 patients. Postoperative spontaneous potentials including fibrillation and sharp waves, and motor unit recruitment in the first dorsal interosseous muscle were obviously improved. A cystic articular branch was confirmed during surgery in all patients. No cyst recurred clinically or on follow-up ultrasonography.

CONCLUSION

The unifying articular theory of intraneural ganglion cysts applies to those located in the ulnar nerve at the elbow. Surgical disconnection of the articular nerve branch from the ulnar nerve eliminated the pathway for cyst recurrence and achieved good long-term outcomes.

The current trend of proximal tibiofibular ganglion cyst: A summary of 7 case series and 61 case reports

Purpose

To review the different types of ganglion cysts surrounding the proximal tibio-fibular joint, their management options, outcomes, and recurrence.

Design

Descriptive analytical review.

Results

7 case series consisting of a total of 159 patients and 61 case reports consisting of 80 patients (with three patients having bilateral pathology) were included in this review. (Total cysts 159 + 83 = 242). The mean age was 41 years, and 71 % of the patients were males. 96.5 % of the cases were managed operatively, out of which 98 % of patients felt improvement in local symptoms and 71.5 % had improvement in neurological symptoms. Complete excision of the cyst is the primary mode of operative management. Many added procedures with complete excision are to mitigate the risk of recurrence. The recurrence rate of aspiration, simple excision alone, simple excision with recurrent articular branch neurectomy, and simple excision with PTFJ procedures were 77 %, 56 %, 11.5 %, and 0 %, respectively. Outcomes beyond recurrence were poorly reported.

Conclusion

There is not enough literature regarding the topic from which any formal systematic review can be done. Our summary suggests that aspiration alone or with steroid injection is associated with the highest recurrence rates among all the procedures. Complete excision with recurrent articular branch neurectomy should be the primary management. Revision cyst excision in isolation is an inadequate treatment option, therefore should be done in conjunction with PTFJ arthrodesis, which reduces the recurrence rates. Better quality studies are needed that report patient-centered outcomes and morbidities following PTFJ procedures.

Tarsal tunnel ganglion cyst: intraneural or extraneural site?

Intraneural ganglion cysts are very uncommon lesions, whose diagnosis has increased since the articular theory and the description of the MRI findings were established. We present a case report of a 59-year-old man with symptoms of tarsal tunnel syndrome. Foot and ankle MRI demonstrated the presence of an intraneural cystic lesion in the posterior tibial neve and its connection with the subtalar joint through an articular branch. The identification of the specific radiological signs like the «signet ring sign» allowed establishing an adequate preoperative diagnosis, differentiating it from an extraneural lesion and facilitating the articular disconnection of the nerve branch during surgery.

Femoral intraneural ganglion cyst: the first confirmed case report

BACKGROUND

Ganglion cysts affecting nerve are rare causes of neuropathy. The formation of intraneural ganglion cysts, once controversial, has recently been clarified. We describe the first modern description of a femoral intraneural ganglion cyst at the hip region.

METHODS

A patient presented with a 1 year history of radiating pain, quadriceps weakness and anteromedial leg numbness was found to have a femoral intraneural cyst with a hip joint connection on MRI.

RESULTS

Surgical disconnection of the articular branch led to improvement of the neuropathy and resolution of the cyst on postoperative MRI.

CONCLUSIONS

The unifying articular (synovial) theory describes the joint origin of intraneural cysts, even when they occur in unusual locations, and their propagation into the parent nerve. Knowledge of this theory can improve outcomes; surgery needs to address the joint origin or capsulolabral defect lest recurrence ensue.

Tibial intraneural ganglion cysts at the superior tibiofibular joint treated with joint resection alone: a proof of concept

BACKGROUND

Intraneural ganglion cysts involving the tibial nerve are rare. Recent evidence has supported an articular (synovial) theory to explain the joint-related origin of these cysts; however, optimal operative treatment for cysts originating from the STFJ remains poorly understood. Therefore, we present a novel strategy: addressing the joint itself without addressing the articular branch and/or the cyst.

METHODS

Records of patients with tibial intraneural ganglion cysts with a connection to the STFJ who were treated with a joint resection alone at a single academic institution were reviewed. The clinicoradiographic features, operative intervention, and postoperative course were recorded.

RESULTS

We identified a consecutive series of 7 patients. These patients (4/7 male, 57%) were 43 (range 34-61) years of age and all presented with symptoms of neuropathy. The patients underwent resection of the synovial surfaces of the STFJ without disconnection of the articular branch or decompression of the cyst. Postoperatively, three patients regained partial motor function (43%, n=7), although four patients noted continued sensory abnormality (57%, 4/7). All six patients with postoperative MRIs had some evidence of regression of the cyst.

CONCLUSIONS

This novel surgical technique serves as a proof of concept-highlighting the fact that treating the primary source (the joint origin) can be effective in eliminating the secondary problem (the cyst itself). While this study shows that this simplified approach can be employed in select cases, we believe that superior results (faster, fuller recovery) can be achieved with combinations of disconnecting the articular branch, decompressing the cyst, and/or resecting the joint.

Recurrent Peroneal Intraneural Ganglion Cyst: Management and Review of the Literature

Intraneural ganglion cysts have been reported to affect the common peroneal nerve. Peroneal intraneural ganglion cysts are managed through surgical intervention. Despite surgical intervention, intraneural ganglion cysts can recur. Common intraneural ganglion cyst recurrence patterns have been proposed based on the initial surgical management of the cyst. These patterns all emphasize the importance of treatment of the proximal tibiofibular (TF) joint to reduce the risk of cyst recurrence. Although joint resection is the favored intervention in the literature, joint arthrodesis is an option for certain patients. Here, we present a case of a peroneal intraneural ganglion cyst and its recurrence in a 36-year-old male who had previously undergone surgical removal of the cyst three months prior, as well as a review of the current literature that aims to add to our current understanding of intraneural cysts.

Cubital Tunnel Syndrome Due to Multiple Intraneural Cysts at Elbow: A Case Report and Review of Literature

Cubital tunnel syndrome is a common disorder that affects the upper limb and involves compression of the ulnar nerve. However, this syndrome is rarely caused by multiple intraneural ganglion cysts. Of all intraneural ganglion cysts, only 9% affect the elbow. This study presents a case report of a 73-year-old female patient who manifested pain, numbness, tingling, and paralysis of the medial aspect of her left forearm, fourth, and fifth fingers of the left hand for six months. Intraoperative findings showed multiple intraneural cysts at the left elbow, which were confirmed via histopathology. The cysts were surgically excised, whereas the ulnar nerve was released into the cubital tunnel and anteriorly transposed. Complete sensory and motor recovery were achieved. Although similar cases of intraneural cysts were reported in the literature, this case has the uniqueness of the unusual number and site of intraneural cysts in the ulnar nerve on the background of osteoarthritic changes. Therefore, the aim of reporting this case is to increase awareness of the presence of these cysts when the symptoms are severe.

Preoperative Imaging of Intraneural Ganglion Cysts: A Critical Systematic Analysis of the World Literature

BACKGROUND

Advancements in imaging and an understanding of the pathomechanism for intraneural ganglion cyst formation have led to increased awareness and recognition of this lesion. However, the precise role of imaging has been advocated for but not formally evaluated.

METHODS

We performed a systematic review of the world literature to study the frequency of imaging used to diagnose intraneural ganglion cysts at different sites and compared trends in identifying joint connections.

RESULTS

We identified 941 cases of intraneural ganglion cysts, of which 673 had published imaging. Magnetic resonance imaging (MRI, n = 527) and ultrasonography (US, n = 123) were the most commonly reported. They occurred most frequently in the common peroneal nerve (n = 570), followed by the ulnar nerve at the elbow (n = 88), and the tibial nerve at the ankle (n = 58). A joint connection was identified in 375 cases (48%), with 62% of MRIs showing a joint connection, followed by 16% on US, and 6% on computed tomography (CT). MRI was statistically more likely to identify a joint connection than was US (P < 0.01). In the last decade, joint connections have been identified with increasing frequency using preoperative imaging, with up to 75% of cases reporting joint connections.

CONCLUSIONS

Preoperative imaging plays an important role in establishing the diagnosis of intraneural ganglion cyst as well as treatment planning. Imaging has proved superior to the sole reliance of operative exposure to identify a joint connection, which is necessary to treat the underlying disease. Failure to identify cyst connections on imaging can result in an inability to truly address the underlying pathoanatomy at the time of definitive surgery, leading to a risk for clinical recurrence. Therefore, management should be guided by an intersection between new knowledge presented in the literature, clinical expertise, and surgeon experience.

Juxtaneural ganglia arising from the hip joint: focus on magnetic resonance imaging findings and clinical manifestations

OBJECTIVE

To present cases of juxtaneural ganglia arising from the hip with a discussion of the magnetic resonance imaging (MRI) findings, presenting symptoms, and possible treatment option.

MATERIALS AND METHODS

Two radiologists performed a consensus review of MRI scans obtained between January 2013 and March 2021 to identify patients with juxtaneural ganglia around the hip. A total of 11 patients with 11 juxtaneural ganglia were identified. Medical records and MRI findings were retrospectively reviewed.

RESULTS

Eight patients had lesions involving the sciatic nerve, and three patients had lesions involving the obturator nerve. Sciatic ganglia arose from a paralabral cyst in the posteroinferior quadrant and continued through a narrow channel running along the posterior acetabulum, showing increased diameter in the sciatic foramen and intrapelvic portion. Obturator ganglia showed a J- or reverse J-shape on the coronal imaging plane and extended from a paralabral cyst in the anteroinferior quadrant via the obturator canal. Nine patients (9/11, 81.8%) had symptoms resembling those of lumbosacral radiculopathy. Four patients underwent arthroscopic surgery, and one patient underwent ultrasound-guided aspiration, all of whom showed partial improvement. Spontaneous decrease in the extent of the ganglion was observed in three patients (3/11, 27.3%).

CONCLUSION

This article describes rare cases of juxtaneural ganglia arising from the hip joint and involving the sciatic and obturator nerves. The lesions share similar MRI findings, and each type of cyst (sciatic or obturator ganglia) involves a specific labral quadrant.

An intraneural ganglion cyst of the ulnar nerve at the wrist: a case report and literature review

Background

Intraneural ganglion cysts of the ulnar nerve at the wrist are rare and poorly understood. We report a case of an intraneural ganglion cyst at the level of the wrist.

Case presentation: A 48-year-old man presented with the complaints of weakness for 6 months and serious aggravation for 1 month in his right hand. After examinations, including ultrasound, the patient was diagnosed with an intraneural ganglion cyst. Intraoperatively, with exposure of the ulnar nerve, we found that the intraneural ganglion cyst was at the level of Guyon’s canal and extended approximately 6 cm proximally. Postoperatively, sensation of the fingers was normal, but atrophy of his muscles and limited straightening of his ring and little fingers were similar to those preoperatively.

Conclusions

Diagnosis of an intraneural cyst before surgery is mostly based on ultrasound and magnetic resonance imaging. Transection of the articular branch is an important measure to prevent recurrence of this cyst. If the ulnar nerve is compressed and causes symptoms, nerve decompression, including removal/aspiration of the cyst, and sometimes external neurolysis of the nerve, are necessary to relieve the symptoms and allow regeneration of the nerve. However, these should be performed without damaging the nerve fascicles.

Detailed Case Reports of Surgical Treatment for Intraneural Ganglion Cysts

Intraneural ganglion cysts are nonneoplastic mucinous cysts that form by the accumulation of thick mucinous fluid in the epineurium of peripheral nerves. Symptoms arise from mechanical compression of adjacent nerve fascicles from the intraneural ganglion cyst, and include local or radiating pain, paresthesias, weakness, and muscle atrophy.

Compressive peroneal neuropathy by an intraneural ganglion cyst combined with L5 radiculopathy: A case report

RATIONALE

Most cases of foot drop are known to result from lower motor neuron pathologies, particularly lumbar radiculopathy and peripheral neuropathy, including common peroneal neuropathy. To improve the prognosis of foot drop, it is important to quickly and accurately diagnose the etiology and provide appropriate treatment.

PATIENT CONCERNS

A 65-year-old female patient with a history of L4-5 intervertebral disc herniation presented with right foot drop that had developed 1 month previously.

DIAGNOSIS

Electrodiagnostic examination revealed common peroneal neuropathy combined with L5 radiculopathy, with the former being the main cause of the foot drop. MRI of the right knee was performed to identify the cause of the peroneal nerve lesion, which revealed an intraneural ganglion cyst in the common peroneal nerve.

INTERVENTIONS

The patient was treated by ultrasound-guided percutaneous cyst aspiration and corticosteroid injection into the decompressed ganglion, followed by strengthening exercise, electrical stimulation therapy, and prescription of an ankle foot orthosis.

OUTCOMES

We confirmed regeneration of the injured peroneal nerve at the follow-up electrodiagnostic examination 12 weeks after the intervention. In addition, the manual motor power test demonstrated an increase in the ankle dorsiflexor function score by one grade.

LESSONS

Diagnosing the cause of foot drop can be difficult with multiple co-existing pathologies, and consideration of various possible etiologies is the key for appropriate diagnosis and treatment. In addition to imaging modalities such as MRI, electrodiagnostic examination can help to improve diagnostic accuracy. Intraneural ganglion cyst of the common peroneal nerve is rare, but should be considered as a possible cause of foot drop.

Intraneural ganglion cyst: a case report and a review of the literature

Background

An intraneural ganglion cyst is a non-neoplastic gelatinous cyst, which can be found within the epineurium of a peripheral nerve and lead to signs and symptoms of peripheral neuropathy. Early diagnosis and appropriate surgical treatment of this condition is a key to a successful outcome.

Materials and methods

We describe a case of a patient with peroneal nerve neuropathy caused by an intraneural ganglion cyst. Postsurgically, only partial relieve of the symptoms was achieved because of delayed diagnosis.

Results

The aetiology of intraneural ganglia is controversial and historically different pathogeneses of this condition have been described. Diagnosis of these cysts is based on MRI. Multiple surgical treatment strategies have been developed based on different pathogenesis of the formation of these cysts, but neuropathy is reversible only, if this condition is diagnosed and treated early.

The cubital tunnel syndrome caused by intraneural ganglion cyst of the ulnar nerve at the elbow: a case report

BACKGROUND

Cubital tunnel syndrome is common nerve compression syndrome among peripheral nerve compression diseases. However, the syndrome caused by intraneural ganglion cysts has been rarely reported. Medical approaches, like ultrasound-guided aspiration and open surgical treatment remain to be discussed.

CASE PRESENTATION

A 57-year-old woman presented with occasional pain, numbness and paralysis in her left hand and a palpable, painless mass in the ulnar side of her left elbow. Ultrasound-guided aspiration of the mass was performed to decompress the ulnar nerve. The patient experienced an evident release of pain in her hand, but symptoms of numbness and paralysis recurred 3 months later which greatly bothered the patient's daily life. After evaluation, we had to perform an open surgery to excise the cyst. External neurolysis and anterior subcutaneous transposition were done. The patient was followed up for 2 years, and she made a complete recovery with no functional limitation.

CONCLUSIONS

The symptoms caused by intraneural ganglion cyst can be alleviated by accurate puncture. But puncture may be not complete and symptoms could recur. Complete external neurolysis can be counted as a complete and reliable treatment. Therefore, early diagnosis, careful preoperative imaging assessment and full decompression can be expected to receive a good rehabilitation.

Degenerative subtalar joints complicated by medial plantar intraneural cysts : cutting the cystic articular branch prevents recurrence

AIMS

The pathogenesis of intraneural ganglion cysts is controversial. Recent reports in the literature described medial plantar intraneural ganglion cysts (mIGC) with articular branches to subtalar joints. 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 treatment of mICGs.

PATIENTS AND METHODS

Between 2006 and 2017, five patients with five mICGs were retrospectively reviewed. There were five men with a mean age of 50.2 years (33 to 68) and a mean follow-up of 3.8 years (0.8 to 6). Case history, physical examination, imaging, and intraoperative findings were reviewed. The outcomes of interest were ultrasound and/or MRI features of mICG, as well as the clinical outcomes.

RESULTS

The five intraneural cysts followed the principles of the unifying articular theory. Connection to the posterior subtalar joint (pSTJ) was identified or suspected in four patients. Re-evaluation of preoperative MRI demonstrated a degenerative pSTJ and denervation changes in the abductor hallucis in all patients. Cyst excision with resection of the articular branch (four), cyst incision and drainage (one), and percutaneous aspiration/steroid injection (two) were performed. Removing the connection to the pSTJ prevented recurrence of mIGC, whereas medial plantar nerves remained cystic and symptomatic when resection of the communicating articular branch was not performed.

CONCLUSION

Our findings support a standardized treatment algorithm for mIGC in the presence of degenerative disease at the pSTJ. By understanding the pathoanatomic mechanism for every cyst, we can improve treatment that must address the articular branch to avoid the recurrence of intraneural ganglion cysts, as well as the degenerative pSTJ to avoid extraneural cyst formation or recurrence. Cite this article: Bone Joint J 2018;100-B:183-9.

Cystic degeneration of the tibial nerve: magnetic resonance neurography and sonography appearances of an intraneural ganglion cyst

Extra- and intraneural ganglion cysts have been described in the literature. The tibial nerve ganglion is uncommon and its occurrence without intra-articular extension is atypical. The pathogenesis of cystic degeneration localized to connective and perineural tissue secondary to chronic mechanical irritation or idiopathic mucoid degeneration is hypothesized. Since the above pathology is extremely rare and the magnetic resonance imaging examination detects the defining characteristics of the intrinsic alterations of the tibial nerve, the authors illustrate such a case of tibial intaneural ganglion cyst with its magnetic resonance neurography and sonography appearances.

Sciatic neurosteatosis: Relationship with age, gender, obesity and height

AIM

To evaluate inter-reader performance for cross-sectional area and fat quantification of bilateral sciatic nerves on MRI and assess correlations with anthropometrics.

METHODS

In this IRB-approved, HIPPA-compliant study, three readers performed a cross-sectional analysis of 3T lumbosacral plexus MRIs over an 18-month period. Image slices were evaluated at two levels (A and B). The sciatic nerve was outlined using a free hand region of interest tool on PACS. Proton-density fat fraction (FF) and cross-sectional areas were recorded. Inter-reader agreement was assessed using intra-class correlation coefficient (ICC). Spearman correlation coefficients were used for correlations with age, BMI and height and Wilcoxon rank sum test was used to assess gender differences.

RESULTS

A total of 67 patients were included in this study with male to female ratio of 1:1. Inter-reader agreement was good to excellent for FF measurements at both levels (ICC=0.71-0.90) and poor for sciatic nerve areas (ICC=0.08-0.27). Positive correlations of sciatic FF and area were seen with age (p value<0.05). Males had significantly higher sciatic intraneural fat than females (p<0.05).

CONCLUSION

Fat quantification MRI is highly reproducible with significant positive correlations of sciatic FF and area with age, which may have implications for MRI diagnosis of sciatic neuropathy.

KEY POINTS

• MR proton density fat fraction is highly reproducible at multiple levels. • Sciatic intraneural fat is positively correlated with increasing age (p < 0.05). • Positive correlations exist between bilateral sciatic nerve areas and age (p < 0.05). • Males had significantly higher sciatic intraneural fat than females (p < 0.05).

Intraneural ganglion cyst of the ulnar nerve in an unusual location: A case report

INTRODUCTION

Intraneural ganglion cysts are benign, mucinous, non-neoplastic lesions of the peripheral nerves. While the most common location of intraneural ganglion cysts is the ulnar nerve and its branches, intraneural ganglion cyst involving the superficial branch of the ulnar nerve has not yet been reported.

PRESENTATION OF CASE

A-25-year-old woman presented with pain and a palpable mass in the hypothenar region of the volar side of her right hand. Her neuromuscular examination was normal. The pain was unresponsive to nonsurgical treatments. After confirming with imaging modalities, the initial diagnosis was considered as an intraneural ganglion cyst arising from superficial ulnar nerve. Excision of the ganglion and exploration of the articular branch (if seen in operation) decision was undertaken by the senior author. Whether MRI or intraoperative exploration, not identified an articular branch.

DISCUSSION

Intraneural ganglion cysts of peripheral nerves may be seen in miscellaneous locations in the body. However, to our knowledge, an intraneural ganglion cyst involving the superficial branch of the ulnar nerve is unique. While a variety of theories have been proposed to enlighten the etiopathogenesis of intraneural ganglia, the latest and most affirmed is the unifying articular (synovial) theory.

CONCLUSION

Intraneural ganglion cysts may be seen on the hypothenar side of the palm. The etiology and treatment of choice are closely associated with each other in this rare disorder. It is important to realize a related articular branch, otherwise the origin of cyst formation remains, and this may cause other para-articular cysts.

Occult Isolated Articular Branch Cyst of the Lateral Plantar Nerve

We present the first known case of cyst fluid localized to an articular branch without involvement of the larger parent nerve. During a routine tarsal tunnel decompression in a patient with fluctuating plantar foot symptoms and "normal" magnetic resonance imaging findings, we identified cyst fluid within an articular branch of the lateral plantar nerve to the subtalar joint. Our incidental intraoperative discovery was corroborated by retrospective review of the magnetic resonance images. Although we do not know whether this cyst was responsible for the patient's complaints, we believe this finding represents a snapshot into the life cycle of intraneural ganglion cysts: either the "birth" of an ultra-early one or the remnant of a once larger one. Both interpretations are consistent with the unifying articular theory and add further insight into the dynamic phases of the progression of intraneural ganglion cysts.

Intraneural Ganglion Cyst of the Ulnar Nerve at the Elbow Masquerading as a Malignant Peripheral Nerve Sheath Tumor

BACKGROUND

Ulnar neuropathy at the elbow (UNE) is the second most common mononeuropathy of the upper extremity. One rare cause of UNE is nerve mass lesions, including intraneural ganglion cysts (IGCs). IGC imaging studies provide important information that may determine the nature of a peripheral nerve mass lesion.

CASE DESCRIPTION

We present the case of a 73-year-old woman who presented with rapid deterioration of left hand function over 2 months with weakness of fine motor control, grip strength, and dysesthesia in the ulnar nerve distribution. Preoperative imaging studies, including magnetic resonance imaging (MRI) of the elbow, postcontrast studies, diffusion-weighted imaging, and apparent diffusion coefficient measurements, suggested a highly cellular tumor. Diffusion tensor tractography also revealed imaging features suggestive of a malignant peripheral nerve sheath tumor. During the operation, a sample of the lesion was sent for frozen section. There were no features of malignancy, and the pathologist could not determine a diagnosis based on the tissue sample sent. An intraoperative decision was made not to divide the ulnar nerve above and below the lesion. The IGC was successfully managed by identifying a suitable plane of dissection and cyst resection.

CONCLUSIONS

This case demonstrates that MRI studies indicating malignant peripheral nerve sheath tumor must be considered with some caution and corroborated with supportive features on operative inspection and biopsy before radical resection is undertaken. Furthermore, for any nerve mass lesion immediately adjacent to a joint, the differential diagnosis of an IGC should be considered.

Subparaneurial ganglion cysts of the fibular and tibial nerves: A new variant of intraneural ganglion cysts

Over the last decade, the mechanism of formation of intraneural ganglion cysts has been established through a meticulous review of clinical findings and correlation with patterns produced on magnetic resonance imaging (MRI). Pathognomonic imaging patterns distinguish these rare lesions from the more common extraneural variants in almost all cases. In this report, we present a new pattern of cyst occurrence in the subparaneurial compartment of the nerve and provide potential anatomic explanations for its pathogenesis. Using an anatomic framework of connective tissue compartments of the nerve, we reviewed 63 (56 fibular and seven tibial) intraneural ganglion cysts in the knee region evaluated at our institution and all reports with MRI in the world's literature for evidence of cyst occurrence in the subparaneurial compartment. We identified six cases (five in the common fibular nerve and one in the tibial nerve) at our institution that had MR evidence of cyst in the subparaneurial compartment with a new complex lobulated pattern. All cases had articular branch connections to the superior tibiofibular joint, which at operation were resected along with the joints. Follow-up revealed complete recovery in all instances and no clinical or radiological signs of recurrence. Three cases out of 80 in the literature exhibited the new complex lobulated MRI pattern. We present a new pattern of intraneural ganglion cyst occurrence in a potential space that surrounds peripheral nerves--the subparaneurial compartment. We believe that the unifying articular theory applies to the pathogenesis and management of these rare variants.