Periosteal ganglion cysts or periosteal ganglia are rather rare types of ganglion cysts that affect the periosteum.

Clinical presentation

Clinical symptoms depend on the location, they have been reported to present with pain, as a firm, painless swelling and were found incidentally.

Pathology

Periosteal ganglion cysts are well-defined, smooth-walled, cystic masses of the periosteum. Similar to other ganglion cysts they are filled with clear, mucinous material and lack a synovial membrane¹.

Etiology

They are thought to be a consequence of mucoid degeneration of the periosteum ¹.

Location

Most commonly they are located in the proximal diaphysis of the tibia near the pes anserinus, other locations affect the other long bones e.g. the femoral intercondylar region, the metatarsal bones or tarsal tunnel ^1-6.

Radiographic features

Plain radiograph

Plain radiographs may show superficial scalloping or cortical erosion as well as signs of reactive bone formation.

MRI

MRI is the best modality for the visualization and evaluation of periosteal lesions ². The typical appearance is that of a well-defined cystic mass arising from the periosteum ^1-3.

• T1: will depend on protein content, but mostly hypointense

• T2: hyperintense

• PDFS/T2FS: hyperintense

Treatment and prognosis

Management options depend vastly on clinical symptoms and location and include conservative measures, image-guided percutaneous aspiration as well as surgical excision ^2-4.

History and etymology

The first descriptions of periosteal ganglion cysts were apparently made by Ollier in 1864 and Poncet in 1874 ^2-4.

Differential diagnosis

Conditions that can mimic the presentation and/or the appearance of periosteal ganglia include ^1,4:

• subperiosteal hematoma

• chronic subperiosteal abscess

• periosteal aneurysmal bone cyst

• hydatid cyst

• periosteal chondroma

• malignant soft tissue tumors

See also

• ganglion cysts

• cyst-like lesions around the knee