Presentation
Right ankle swelling for 5 years. Stable in size. No history of pain, or trauma.
Patient Data
A well-defined focal oval-shaped, soft tissue swelling measuring roughly 3.0 x 2.0 cm is seen along the anterior aspect of the right ankle joint. No calcifications are seen in it. No significant abnormality is seen in the underlying bones and joints.
A well-defined soft tissue mass lesion measuring 3.0 x 3.0 x 5.0 cm is seen just anterior to the right ankle joint. This lesion has heterogeneous T1 and T2 signal intensity and well-defined outer margins showing smooth pressure erosions on the talar neck and distal anterior tibia. No fat component, hemorrhage, or calcifications are seen in it. The lesion shows significant enhancement in the post-contrast study and central degeneration. No bone marrow edema is seen in the underlying bones. No abnormal ankle joint effusion is seen. The supporting ligaments of the ankle are preserved.
Case Discussion
Impression: Solitary localized soft tissue mass lesion in close relation to the right ankle joint, which is likely a tenosynovial giant cell tumor. Possible imaging differential diagnoses include Pigmented villonodular synovitis (PVNS), desmoid tumor, fibroma of the tendon sheath, and ganglion cyst.
The case was reviewed by the musculoskeletal radiologist and oncologic orthopedic surgeon. She underwent ultrasound guided biopsy of the lesion followed by its complete surgical excision.
Histopathological analysis of both specimens (ultrasound guided biopsy as well as surgical excision): Tenosynovial giant cell tumor with a prominent xanthomatous component. No evidence of malignancy seen.