Metachronous ganglion cysts: illustrative case - Case lessons - Issue 11 - Lessons

Q: Why did the case challenge the articular theory of ganglion cyst formation?

No discrete articular branch connection was identified on preoperative imaging or intraoperatively, yet sequential cyst recurrences still occurred. This made the case an outlier to the theory’s expected pathway documentation.

Q: What cysts developed in sequence after treatment of the original intraneural cyst?

After resolution of the original ulnar intraneural cyst, an adventitial ulnar artery cyst developed. Subsequently, that resolved and a small extraneural (soft tissue) ganglion cyst emerged.

Sep 29, 2026

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Metachronous ganglion cysts are presented through a case of ulnar neuropathy at Guyon’s canal, where recurrent cyst formation challenged the prevailing articular theory. Serial MR images and surgical findings were reevaluated after multiple operations, identifying no discrete articular branch at first presentation. Instead, an initially treated ulnar intraneural cyst resolved, followed by sequential development of an adventitial ulnar artery cyst and then an extraneural soft-tissue ganglion arising from the same wrist joint. The discussion emphasizes unified articular mechanisms, scarring effects, and pressure dynamics along neighboring capsular pathways.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages3

Reading Time8 min

AccessFree to download

Case Lessons

Background

Observations

Lessons

Illustrative Case

Discussion

JOURNAL OF NEUROSURGERY: Case Lessons J Neurosurg Case Lessons 11(1): CASE25618, 2026 DOI: 10.3171/CASE25618 Metachronous ganglion cysts: illustrative case Robert J. Spinner, MD,1 B. Matthew Howe, MD,2 and Daniel Reiser, MD3 1Department of Neurologic Surgery and 2Department of Radiology, Mayo Clinic, Rochester, Minnesota; and 3Department of Hand Surgery and Orthopedics, Faculty of Medicine and Heath, Örebro University, Örebro, Sweden BACKGROUND Ulnar neuropathy at Guyon’s canal is rare, but when it occurs, it is frequently due to underlying masses, including extraneural and intraneural ganglion cysts, as well as adventitial cysts. The pathogenesis of these cysts, especially at a rare site, remains controversial. The articular theory, which is gaining popularity, posits that a joint connection via a nerve (or vascular) branch to a neighboring joint represents the pathway for their formation and propagation. OBSERVATIONS A recently published case of a patient with an ulnar intraneural ganglion at the wrist with a series of postoperative cystic recurrences was reevaluated, as it challenged the articular theory. No discrete articular branch had been identified on imaging or at surgery. Serial MR images were reinterpreted, which revealed that the original intraneural cyst was treated; new sequential cysts—an adventitial cyst and then a soft tissue ganglion—developed, all arising from the same wrist joint. LESSONS This case strengthens the principles of the articular theory for intraneural ganglion, adventitial, and soft tissue ganglion cysts. A small wrist connection from the ulnar intraneural ganglion was unrecognized and untreated. Scarring disrupted the original nerve pathway and pressure dynamics. New cysts developed through neighboring joint capsular rents along different pathways into other “compartments”(vessel or soft tissues) . [https://thejns.org/doi/abs/10.3171/CASE25618](https://thejns.org/doi/abs/10.3171/CASE25618) KEYWORDS intraneural ganglion cyst; unified theory; articular branch; ulnar nerve; adventitial cyst Ulnar neuropathy at the wrist (Guyon’s canal) is relatively uncommon and represents < 1% of cases of ulnar neuropathy. Recently, a patient treated for ulnar neuropathy at Guyon’s canal underwent several operations over the course of a few years for an intraneural ganglion cyst. Postoperatively, he developed recurrent cysts. The fact that no discrete articular branch connection was documented on preoperative imaging or intraoperatively, and the cysts recurred despite several surgeries, represented an outlier for the articular theory, which has been gaining support. We present this case to highlight several important features regarding the formation and propagation of these rare cysts: 1) an articular origin, 2) the path of least resistance, and 3) the role of pressures and pressure fluxes—all consistent with the underlying principles of the unified articular theory.1 Illustrative Case We present a previously reported case2 of a 53-year-old man who initially presented with clinical findings of ulnar neuropathy at the wrist. The patient underwent a series of three surgeries at the wrist/distal forearm over several years: 1) initial decompression of Guyon’s canal in a primary orthopedic clinic (cystic changes in the ulnar nerve were noted but not treated; the patient was referred to the Department of Hand Surgery at the university hospital, a tertiary facility), 2) resection of a large intraneural cyst after persistent symptoms, and 3) reresection of a ganglion cyst 18 months later for recurrent symptoms. We read the paper,2 intrigued by the recurrences that remained “somewhat unclear” to the authors of the publication as well as our group, which has promoted the articular theory. With the help of the authors of the paper, we reviewed the initial MRI study (2020) and the MRI studies at recurrences (2023 and 2024) . Reinterpretation of these three sets of images revealed the followin

FAQs

Why did the case challenge the articular theory of ganglion cyst formation?

No discrete articular branch connection was identified on preoperative imaging or intraoperatively, yet sequential cyst recurrences still occurred. This made the case an outlier to the theory’s expected pathway documentation.

What cysts developed in sequence after treatment of the original intraneural cyst?

After resolution of the original ulnar intraneural cyst, an adventitial ulnar artery cyst developed. Subsequently, that resolved and a small extraneural (soft tissue) ganglion cyst emerged.

How did scarring and pressure dynamics contribute to new cyst development?

Scarring disrupted the original nerve pathway and pressure dynamics, allowing new cysts to develop through neighboring joint capsular rents into other compartments. These events were consistent with unified principles involving pressure fluxes and least-resistance pathways.

Sep 29, 2026

Upload by Blue Pony