title: Myositis ossificans circumscripta of the knee improved by alendronate.
abstract: Myositis ossificans circumscripta (MOC) is a rare benign disorder characterized by heterotopic ossification of soft tissues. We report a case in a 21-year-old male who presented with knee pain after strenuous physical activity. Evidence of inflammation of the knee and a hard swelling in the subquadricipital area were the main physical findings. The initial plain radiographs showed a subpatellar soft tissue mass containing flocculent calcifications. Over the next 2 months, the calcific deposits organized into a calcified mass. Magnetic resonance imaging findings were nonspecific, with a mass within the vastus medialis muscle generating low signal on T1 images and high signal on T2 images, without postgadolinium enhancement. Computed tomography showed several calcific deposits arranged in a ring, strongly suggesting MOC. Histological examination of a biopsy specimen confirmed this diagnosis. Alendronate therapy given for 6 months was followed by marked clinical improvement, obviating the need for surgery.
authors.affiliation: Internal Medicine Department, Domestic Security Forces Hospital, La Marsa, Tunisia. hend.benammar@rns.tn
authors.forename: Kaouther Saadallaoui
authors.initials: KS
authors.lastname: Ben Hamida
authors.forename: R
authors.initials: R
authors.lastname: Hajri
authors.forename: H
authors.initials: H
authors.lastname: Kedadi
authors.forename: H
authors.initials: H
authors.lastname: Bouhaouala
authors.forename: M Hadj
authors.initials: MH
authors.lastname: Salah
authors.forename: A
authors.initials: A
authors.lastname: Mestiri
authors.forename: L
authors.initials: L
authors.lastname: Zakraoui
authors.forename: M H
authors.initials: MH
authors.lastname: Doughi
mesh_terms: D000328:Adult; D019386:Alendronate / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009221:Myositis Ossificans / Q000175:diagnosis* / Q000188:drug therapy*; D010147:Pain Measurement; D011379:Prognosis; D016059:Range of Motion, Articular / Q000502:physiology; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D019386:Alendronate