Synovial chondromatosis of the subtalar joint: a case report and review of the literature

[Foot and ankle tumours : Part II: Malignant bone tumours and soft tissue tumours of the foot with differential diagnostic hints]

CLINICAL ISSUE

Both benign and malignant tumours are encountered in the foot and ankle. Due to their rarity, however, diagnosis is often uncertain. Usual criteria such as tumour size, invasiveness or pain fail to differentiate benign from malignant neoplasias.

STANDARD RADIOLOGICAL METHODS

Plain radiography and-due to the complex foot anatomy-CT are important in the diagnostic evaluation of primary bone tumours. In the case of soft tissue tumours, ultrasonography is used to identify ganglion cysts. Tumour evaluation and staging are then performed using MRI. Nuclear imaging comes into play when multifocal, metastatic or systemic spread of the disease is suspected or if a biopsy procedure is planned.

METHODICAL INNOVATIONS

For the role of dual-energy CT, please refer to part I. Whether dual-energy CT is suitable to assess bone marrow oedema patterns is still debated.

SPECIAL FEATURES OF FOOT AND ANKLE TUMOURS

Primary bone tumours generally present in the ankle or the hindfoot. Malignant bone tumours, e. g. chondrosarcoma, are primarily found in the latter. On the other hand, soft tissue tumours generally present in the mid- and forefoot regions.

ACHIEVEMENTS

While the radiologic diagnostic evaluation of pedal bone tumours is quite reliable, caution is urgently needed in the case of soft tissue tumours because there are many confusing differential diagnoses.

PRACTICAL RECOMMENDATIONS

Proper X‑ray examination of the foot (at least in two plains) or with special views according to bony pathology is needed. All soft tissue masses that are not cysts should be evaluated further. MRI remains the diagnostic modality of choice but never stands alone! Caution: Size and well-defined margins of pedal soft tissue tumours are not considered criteria regarding whether a tumour is malignant or not.

Primary synovial chondromatosis of the subtalar joint: case report and review of the literature

Primary synovial chondromatosis is a rare benign condition of uncertain etiology manifested by synovial proliferation. In the radiology literature, there is only 1 prior case report of primary synovial chondromatosis involving the subtalar joint with only partial description of the imaging appearance. We present a 28-year-old female with primary synovial chondromatosis of the subtalar joint and conduct a literature review of the imaging features of primary synovial chondromatosis presenting in the feet.

Pediatric Subtalar Joint Synovial Chondromatosis Report of a Case and an Up-to-date Review

Synovial chondromatosis is a rare, usually benign disorder affecting the population predominantly in the third and fourth decades of life and mainly involving the large weightbearing joints of the lower limb-the knees and the hip. In this report, we highlight an unusual pediatric clinical presentation of synovial osteochondromatosis involving the subtalar joint and discuss its surgical management; we also provide a comprehensive up-to-date literature review of the disorder. This patient was successfully treated with en masse surgical excision. He has been doing well, with complete pain relief and improved range of motion at 1-year follow-up. An exceptional involvement of the subtalar joint and an unusual presentation in the pediatric age group makes this case unique.

Tenosynovial Osteochondromatosis of the Flexor Hallucis Longus Tendon Treated by Tendoscopy

Tendosynovial chondromatosis of the foot and ankle is a rare disease entity. We reported 3 patients with tenosynovial osteochondromatosis of flexor hallucis longus. They were successfully treated by arthroscopic synovectomy and removal of the loose bodies.