Extraskeletal Osteochondroma of the Medial Arch of the Foot

Abstract

Therapeutic, Level IV, Case study.

Giant Solitary Synovial Osteochondroma of the Subtalar Joint

“…Extraskeletal osteochondroma is histologically similar to conventional osteochondroma, but it will not be attached to a parent bone or joint (11). This diagnosis was excluded in the present patient, because the mass had arisen from the posterior subtalar joint.…”

“…Synovial osteochondromatosis can be found equally in males and females, occurring most frequently in those aged 30 to 50 years (11). Giant solitary synovial chondroma is a rare disease entity and has been reported only in case reports or series.…”

Rearrangement of chromosome bands 12q14~15 causing HMGA2-SOX5 gene fusion and HMGA2 expression in extraskeletal osteochondroma

“…The second variant is the rare extraskeletal (or soft tissue) osteochondroma. The latter is defined as a single mass that is peripherally encased by mature hyaline cartilage, has an osseous centre, shows an overall organization similar to that of a conventional osteochondroma but the lesion cannot be intra-articular or in any way be attached to bone ( 2 – 4 ).…”

“…Extraskeletal osteochondromas have also been found near the hip ( 16 ), in the buttocks ( 17 ), and in the nape area ( 18 ). They may display cellular atypia but they do not metastasize or undergo malignant transformation ( 2 – 4 ). Although various mechanisms have been suggested for the cause of extraskeletal osteochondroma ( 3 , 4 ), its etiology and pathogenesis are unknown and there is not cytogenetic or molecular genetic information about the disease.…”

Misdiagnosis of Extraskeletal Osteochondroma in the Foot

“…It is particularly painful along the plantar weight-bearing aspect. Thus, it has been encountered along the medial arch 13,15 , under the metatarsal shaft 16 , beneath the metatarsal head and metatarsophalangeal joint. 11,17…”