title: Osteochondrolipoma Presenting as a Popliteal Cyst.
abstract: Here, we describe a popliteal mass that was initially misdiagnosed as a simple popliteal cyst, which finally turned out to be osteochondrolipoma. A 63-year-old housewife presented with sustained knee pain in association with a palpable mass on the popliteal fossa. The mass was in the posteromedial area and soft, non-tender, non-movable in the posteromedial area. Using plain radiography, the mass appeared as a round, soft tissue density lesion containing bony fragments. We performed an ultrasound-guided needle biopsy in conjunction with magnetic resonance imaging, followed by an open excisional biopsy. Microscopically, histological sections showed a lipoma with cartilaginous and osseous differentiation, finally diagnosed as osteochondrolipoma. In conclusion, popliteal masses are not always simple cysts, and the evaluation of masses in the popliteal fossa is always necessary.
authors.affiliation: Department of Orthopaedic Surgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Young-Joon
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Orthopaedic Surgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Jeong-Ho
authors.initials: JH
authors.lastname: Kang
authors.affiliation: Department of Pathology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Gil-Hyun
authors.initials: GH
authors.lastname: Kang
authors.affiliation: Department of Radiology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Soo-Jung
authors.initials: SJ
authors.lastname: Choi
mesh_terms: D005260:Female; D006801:Humans; D008067:Lipoma / Q000150:complications / Q000175:diagnosis*; D008875:Middle Aged; D015831:Osteochondroma / Q000150:complications / Q000175:diagnosis*; D011151:Popliteal Cyst / Q000209:etiology; D012983:Soft Tissue Neoplasms / Q000150:complications / Q000175:diagnosis*
keywords: Biopsy; Neoplasm; Popliteal cyst