Arteriovenous synovial hemangioma of the popliteal fossa diagnosed in an adolescent with history of unilateral congenital clubfoot: case report and a single-institution retrospective review.

Synovial hemangioma (SH) is a very rare soft tissue tumor; in our department, SH represented 0.07% from all soft tissue tumors (one case from 1311 soft tissue tumors), and 0.78% from all excised hemangiomas (one case from 128 hemangiomas) diagnosed over a five-year period. The aim of this paper was to present the clinicopathologic characteristics of hemangiomas and particularities of one SH of the popliteal fossa diagnosed in an athletic adolescent with previously corrected congenital clubfoot. To our knowledge, this is the 275 case of reported SH. A 13-year-old trick cyclist presented with two-year history of slowly growing mass of the left posterior fossa. The magnetic resonance imaging of the left knee showed a juxta-articular mass with intramuscular component. Open excision of the tumor and partial removal of the synovial membrane was the therapy of choice. Histopathological examination revealed clusters of large arteries and veins embedded in a fibrotic tissue, the tumor mass being lined by synovial membrane. Intramuscular growing was also confirmed. Without any other postoperative therapies, no recurrence or functional disorders were noted after 21 months of follow-up. SH of the knee should be excised as soon as possible to avoid complications such as muscle invasion and risk of recurrence.