Subperiosteal ganglion cyst of the tibia. A communication with the knee demonstrated by delayed arthrography

A case report on rare occurrence of periosteal ganglion cyst in femoral intercondylar region

Ganglions are the cysts derived from myxomatous degeneration of periarticular tissue, commonly found around wrist and foot. Ganglion cysts are uncommon in Knee region and if present their occurrence is mostly incidental and benign. Based on their location, this could be extraarticular or intraarticular. Lesions with similar pathology in subchondral region around joints are lesser common entity called Intraosseous ganglions. Rarer still is the lesion produced by myxomatous degeneration of periosteum of long bone, called periosteal ganglion. We here present a case of 35 year old Male with gradual onset, poorly localised pain behind left knee which was radiologically suggestive of periosteal ganglion, eroding the posterior aspect of femur and confirmed histopathologically following the excision of a lesion from posterior aspect of femoral condyles.

Tibial periosteal ganglion cyst: The ganglion in disguise

Soft tissue ganglions are commonly encountered cystic lesions around the wrist presumed to arise from myxomatous degeneration of periarticular connective tissue. Lesions with similar pathology in subchondral location close to joints, and often simulating a geode, is the less common entity called intraosseous ganglion. Rarer still is a lesion produced by mucoid degeneration and cyst formation of the periostium of long bones, rightly called the periosteal ganglion. They are mostly found in the lower extremities at the region of pes anserinus, typically limited to the periosteum and outer cortex without any intramedullary component. We report the case of a 62 year-old male who presented with a tender swelling on the mid shaft of the left tibia, which radiologically suggested a juxtacortical lesion extending to the soft tissue or a soft tissue neoplasm eroding the bony cortex of tibia. It was later diagnosed definitively as a periosteal ganglion in an atypical location, on further radiologic work-up and histopathological correlation.

MR Imaging of Cysts, Ganglia, and Bursae About the Knee

Cystic lesions around the knee comprise a diverse group of entities, ranging from benign cysts to complications of underlying diseases such as infection, arthritis, and malignancy. Their diverse causes result in varied prognoses and therapeutic options. Although the presentation of cystic masses may be similar, their management may differ, thus highlighting the importance of appropriate categorization. MR aids in the characterization of lesions by first localizing them, and then defining their relationship with adjacent structures and identifying any additional abnormalities. For the purpose of this article, the authors limit the scope of their discussion to benign cysts, ganglia, and bursae about the knee.

The use of MR arthrography to document an occult joint communication in a recurrent peroneal intraneural ganglion

The pathogenesis of intraneural ganglia remains controversial. Only half of the reported cases of the most common type, the peroneal nerve at the fibular neck, have been found to have pedicles connecting the cysts to neighboring joints detected with preoperative imaging or intraoperatively. We believe that all intraneural ganglia arise from joints, and that radiologists and surgeons need to look closely preoperatively and intraoperatively for connections. Not identifying these connections with imaging and surgical exploration has led not only to skepticism about an articular origin of the cyst, but also to a high recurrence rate after surgery. We present a patient who had two recurrences of a peroneal intraneural ganglion in whom a joint connection was not detected on previous MRIs and operations. Reinterpretation of the original films and high-resolution MRI demonstrated an "occult" joint connection to the superior tibiofibular joint. MR arthrography performed after exercise and 1 h delay, however, clearly showed the connection and communication. The joint connection was then confirmed at surgery through an articular branch. Postoperatively the patient regained nearly normal neurologic function, and follow-up MRI showed no cyst recurrence. MR arthrography with delayed imaging should be considered in cases of intraneural ganglia when a joint connection is not obvious on MRI.

Subperiosteal ganglion associated with Paget's disease of bone

Tumoral lesions related to Paget's disease may be classified as malignant, benign or pseudotumoral. While sarcomatous degeneration is the most feared complication, awareness of benign and pseudotumoral lesions is essential for assisting in accurate histological interpretation of the biopsy sample, which may avoid unnecessary repeat biopsies. We present the first case of a juxta-articular subperiosteal ganglion associated with Paget's disease, with classic imaging characteristics, especially on CT examination. The well-defined soft tissue mass at the medial aspect of the obturator rim, adjacent to a small fracture in pagetic quadrilateral plate, showed an ossified rim and internal gas lucencies, these being the hallmarks of a juxta-articular subperiosteal ganglion. On MRI, the lesion was of intermediate signal intensity on T1-weighted sequences, increased signal intensity on T2-weighted sequences, with rim enhancement after gadolinium contrast injection and preservation of fatty marrow signal of the underlying pagetic bone. Identification of the entity avoided an unnecessary biopsy or surgical intervention.

Intraneural ganglion cysts: a case of sciatic nerve involvement

The pathogenesis of intraneural ganglion cysts is unknown. Some authors have established a connection between the cysts and the joint, while others have failed to find this communication. Most intraneural ganglion cysts occur in the proximity of a joint. We present the case of a 53-year-old Caucasian male with an intraneural cyst of the sciatic nerve located high above its bifurcation and without a connection to the joint. The lesion was microsurgically removed in toto. There was no recurrence of the cyst at follow-up 9 months postoperatively; complete resolution of the clinical symptoms occurred within 8 months of surgery. This case shows that ganglion cysts can occur in locations far from a joint, supporting the extra-articular embryonic synovial remnant theory of their genesis.