title: Soft-tissue osteochondroma in the calcaneal pad: a case report.
abstract: Soft-tissue osteochondromas of the foot are infrequently occurring lesions. A 65-year-old woman presented with soft-tissue osteochondroma in the soft tissues superficial to the plantar aspect of the calcaneus. The mass was densely ossified without cortical destruction or other alteration in the adjacent calcaneal bone on x-rays and computed tomography images. A 99m Tc bone scan showed a focal area of an increased uptake at the site of the mass below the calcaneus. Magnetic resonance imaging demonstrated high signal mass on T1-weighted images, isointense to fatty marrow, adjacent to the thickened plantar aponeurosis. The mass was completely excised. Histologically, mature lamellar bone was seen centrally, and the periphery was capped with hyaline cartilage. Since the tumor was located in the plantar aponeurosis and comprised of a single nodule of well-developed bone with well-organized endochondral ossification, the pathogenesis of this lesion might be related to metaplasia.
authors.affiliation: Department of Orthopedic Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakanishi
authors.forename: N
authors.initials: N
authors.lastname: Araki
authors.forename: K
authors.initials: K
authors.lastname: Mukai
authors.forename: H
authors.initials: H
authors.lastname: Ohno
authors.forename: Y
authors.initials: Y
authors.lastname: Matsui
authors.forename: T
authors.initials: T
authors.lastname: Hosoya
mesh_terms: D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006365:Heel / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008875:Middle Aged; D015831:Osteochondroma / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*