CASE REPORT Osteochondroma of the hip with adjacent bursal chondromatosis Elaine S. Gould & Kevin S. Baker & Mingqian Huang & Fazel Khan & Syed Hoda Received: 3 March 2014 /Revised: 31 May 2014 /Accepted: 24 June 2014 # ISS 2014 Abstract It is well established that irregular bursae can form adjacent to an osteochondroma (bursa exostotica) as a result of mechanical irritation and that these bursae can be complicated by inflammation, hemorrhage, or infection. Bursal chondromatosis is a rare complication, with only seven pub- lished cases in the literature according to our searches. We present the case of a 53-year-old female who presented with slowly progressive left hip/thigh pain and was found to have an osteochondroma arising from the lesser trochanter with numerous ossified bodies in the adjacent soft tissues. MRI demonstrated osteochondral bodies in a fluid-filled bursa ad- jacent to the osteochondroma, with several of the bodies noted to be fairly displaced from the osteochondroma cartilaginous cap. At surgery, the osteochondroma was removed and nu- merous bodies of varying sizes were excised, some of which were noted to be adherent to the bursal lining and others that were separated/distant from the cartilage cap. The question arises as to whether this process represents bursal chondromatosis resulting from benign neoplasia of cells lining the abnormal bursa, “ cartilage shedding ” from the osteochondromatous cap, or both. The purpose in presenting this case is to introduce a rare complication of an osteochondroma, demonstrate that soft tissue calcification and osteochondral densities displaced from an underlying osteochondroma are not always the result of sarcomatous degeneration, and provide support for the theory that cells lining a bursa in a nonphysiologic location can undergo be- nign neoplasia with subsequent formation of osteochondral bodies. Keywords Chondromatosis . Synovial chondromatosis . Osteochondroma . Bursal osteochondromatosis . Imaging of bursal chondromatosis Introduction While often painless, osteochondromas can occasionally pres- ent with symptoms related to fracture, nerve or soft tissue impingement, malignant degeneration, and bursa formation [1, 2]. Bursal formation adjacent to an osteochondroma was initially termed “exostosis bursata” in 1891 [3, 4]. It is now well known that this osteochondroma complication can pres- ent with pain, swelling, or an enlarging palpable mass. The bursa can also become inflamed, infected, or hemorrhagic, and can rarely be associated with bursal chondromatosis, a rare complication with only about seven cases reported in the medical literature. Synovial chondromatosis is classified by the World Health Organization (WHO) as a benign neoplasm and has both primary and secondary forms [5]. Multiple cartilaginous nod- ules form within the synovium (typically in joints, but also in tendon sheaths and bursae), some of which can undergo calcification/ossification and become partially or completely loose within synovial fluid. The purpose of this article is to introduce the reader to a rare osteochondroma complication, demonstrate that soft tissue calcification and osteochondral densities displaced from an underlying osteochondroma are not always the result of E. S. Gould : K. S. Baker (*) : M. Huang Department of Radiology, Stony Brook University Medical Center, HSC Level 4, Room 120, East Loop Road, Stony Brook, NY 11794, USA e-mail: kevin.baker@sbumed.org F. Khan Department of Orthopedic Surgery, Stony Brook University Medical Center, HSC Level 18, East Loop Road, Stony Brook, NY 11794, USA S. Hoda Department of Pathology, Stony Brook University Medical Center, HSC Level 2, East Loop Road, Stony Brook, NY 11794, USA DOI 10.1007/s00256-014-1954-y Skeletal Radiol (2014) 43:1743–1748 /Published online: Ju 2014 8 ly