Skeletal Radiol (1995) 24:613-616 Skeletal Radiology Bilateral stress fracture of the clavicle Emilio Calvo, M.D., Darlo Fermindez-Yruegas, M.D., Luis Alvarez, M.D., Jos~ C. de Lucas, M.D., Carlos Vallejo, M.D. Department of Orthopaedic Surgery and Traumatology, Fundacidn Jim~nez Dfaz, Universidad Aut6noma, Madrid, Spain Case report A 26-yer-old, previously healthy sec- retary had initially been trated else- where because of a vague pain over her left clavicle. Radiographs taken at that time were considered normal, although a faint vertical hairline frac- ture line could be appreciated(Fig. 1) on the inner third of the clavicle. Routine laboratory studies were within normal limits. Analgesics and limited activity relieved the symp- toms. However, an increasing swell- ing over the clavicle became progres- sively evident 4 weeks later and the patient was referred to our hospital 4 months after the beginning of the symptoms. She was neither athleti- cally active, nor could she recall a specific injury or history of fever, The initial physical examination at our institution revealed a hard bony mass measuring 5x3 cm on the medial third of the clavicle. The overlying skin was mobile, with no erythema or other changes. The shoulder had a full range of motion, although abduction against resistance was slightly painful. Routine laboratory studies, eryth- rocyte sedimentation rate, C-reactive protein, alkaline phosphatase, vita- min D and serum calcium and phos- phorus tests disclosed no abnormali- ties. Urinanalysis findings were with- in normal limits. Correspondence to: E. Calvo, Virgen de Ar~nzazu, 1, E-28034 Madrid, Spain Plain radiographs and convention- al tomograms (Fig. 2) demonstrated a wide fracture line with thick scle- rotic margins. Bone scanning with technetium-99-methylene disphos- phonate revealed tracer accumultion at the same site. Diagnostic possibilities included fracture nonunion, low-grade infec- tion, and neoplasm. A percutaneous needle biopsy was performed but the histopathologic analysis was incon- clusive because of insufficient mate- rial, so surgical exploration was planned. The segment resected was replaced by an autogeneousfibular graft. The patient was asymptomatic un- til 3 years later, when she presented with an identical slowly growing mass in her right clavicle. Laboratory investigations were repeated, yield- ing no abnormalities. Radiographic studies (Fig. 3) showed a transverse fracture line in the medial clavicle, and a discontinuity of the superior cortex with a faint fracture line could be appreciated on magnetic reso- nance imaging (Fig. 4). No other ab- normalities in bone or soft tissues were found. At operation, the fracture of the left clavicle was exposed, new bone formation was noted about the medi- al clavicle, and the bone on either side of the fracture was found to be softened. At this point, a wide exci- sion of the mass was done in order to reach normal-looking bone, Histologic examination of the re- sected portion of the clavicle re- vealed newly formed bone with in- tense sclerosis surrounded by woven bone with active osteoblasts and sep- arated by loose connective tissue - evidence of a healing fracture (Fig. 5). No characteristics of neoplasia, infection, or metabolic bone disease could be found. Based on these histologic and ra- diographic features, a diagnosis of stress fracture of the clavicle was made. Fig. 1. Anteroposterior radio- graph of the left clavicle at the time of presentation. There is an absence of the inferior cor- tex and a faint vertical fracture line can be appreciated in the medial clavicle 9 1995 International Skeletal Society