ORIGINAL ARTICLE Diagnosis of Paget's disease from chest radiographs: The~~dense coracoid sign" Abstract Incidental Paget's disease of the shoulder as detected on chest radiographs is considered. Five patients demonstrated typical proximal humeral pagetoid involvement, but involvement of the acromiocoracoid or glenocoracoid parts of the scapula was twice as frequent. The dense coracoid was a constant feature and this sign should be sought on chest radiographs especially in the older patient. Introduction The radiological features of Paget's dis- ease of the shoulder were noted on chest radiographs in 16 patients. The parts of the shoulder girdle involved were analysed and the prevalence of humeral and scapular involvement determined. WFC van Gelderen . MBChB. FFRad (D) (SA) Tygerberg Hospital and the University of Stellenbosch, Cape Town Methods and results The chest radiographs of 16 patients with shoulder girdle involvement due to Paget's disease were retrospectively is SA JOURNAL OF RADIOLOGY. November 1996 reviewed. Infive patients (30%) the diag- nosis of Paget' s disease was made meiden- tally from chest x -rayswith a localized view of the shoulder. A frontal radiograph of the pelvis and a lateral film of the skull con- £rmed the diagnosis. In a further Ilpatients, radiographs of the pelvis and! or skull were available in conjunction with chest x-rays, and shoulder girdle involvement was seen as part of widespread Paget's disease. The patients ranged in age from 44-79 years (average 65 years), 12 males and 4 fe- males. One patient was black, 4 were Cau- casian and 11 of mixed descent. Chest ra- diographs were requested for further evalu- ation of pulmonary or cardiac disease and no shoulder complaints were mentioned on the request forms. The shoulder girdle involvement was carefully analysed in each patient. In one patient both proximal humeri and clavicles were involved symmetrically and exten- sively by coarse sclerotic Paget's disease. In five patients only the proximal humerus was involved, unilateral in two patients and bilateral in three patients. In ten patients the scapula only was affected, bilateral acromiocoracoid involvement in one pa- tient, and unilateral involvement in the re- mainder. (Five left side,four right side). The unilateral disease included: acromiocoracoid only (five patients), glenocoracoid only (three patients) and acromioglenocoracoid disease (one pa- tient). Sclerosisof the coracoid, whether ac- companied by acromial or glenoid involve- ment, was detected in all cases of scapular involvement Radiographs of the pelvis demonstrated Paget's diseasein 13,were normal in one and not available in two patients. The lateral skull x-rays showed involvement by Paget's disease in eight, were normal in three and not available in five patients. The above features are illustrated (Fig- ures 1-3).Achestx-rayina62yearoldman demonstrated incidental sclerosis of the topage19 Diagnosis of Paget's disease frorn chest radiographs: The "dense coracoid sign" from page 18 coracoid and acromial processes of the left scapula (Figure 1). Pelvis and skull x-rays demonstrated extensive Paget's disease. Eight years later features on chest Figure 1: Chest demonstrates density and expansion of the acromiocoracoid aspect of the left scapula (arrow) without the humeral head being affected. Features are consistent with Pagel's dise . radiographs remained unchanged but the pagetoid involvement of the pelvis and skull had become far more advanced. A 52 year old man presented with a spontaneous left pneumothorax and in- creased density of the right acromiocoracoid scapula was noted on a chest radiograph (Figure 2). A frontal Figure 2: Predominant involvement of acromiocoracoid part of right scapula due to Paget's disease. Glenoid affected to a lesser degree and humerus normal. Note expansion and sclerosis of coracoid process discovered incidentally on chest x- ray. pelvic radiograph demonstrated involve- ment by Paget's disease but the lateral skull x -ray was normal. A 65 year old man was referred for a chest x -ray because of respiratory symp- toms. Infective changes were noted in the left lower lobe but incidental increased density and expansion of the left glenocoracoid scapula was also noted (Fig- ure 3).A radiograph of the pelvis con:6rmed Figure 3: Marked pagetoid involvement of glenocoracoid aspect of left scapula with acromion less affected and proximal humerus unaffected. Incidental finding on chest radiograph and x-ray pelvis confirmed diagnosis of Paget's disease but radio- graphs of the skuif demonstrated unsuspected multiple myeloma. signs of Paget's disease. A lateral skull x-ray showed no pagetoid features but instead demonstrated signs of co-existing multiple myeloma. The latter diagnosis was subse- quently confirmed clinically. Discussion Paget's disease may affect one bone or many and its distribution tends to be wide- spread and haphazard. The bones most of- ten affected are the pelvis,femur, tibia,lower part of the spine and the skull, whereas the clavicle, ribs, sternum and the bones of the arm are lessoften aflected.' The scapula and thehumerushavebeenidentifiedasunu- sual sitesofinvolvement-" Our experience has been different, with shoulder involve- ment being more common, however only a small number of patients has been 19. SA JOURNAL OF RADIOLOGY· November 1996 considered. The prevalence of Paget' s dis- ease in South Africa has previously been assessed" Itis considered to be rare amongst the black races of theAfrican continent. Ofspeci:6.cinterest isthat Paget's disease of the shoulder can be diagnosed from chest radiographs, and the disgnosis can then be confirmed by taking x-rays of the pelvis and skull. In Dveoutofl6 patients involementwas limited to the proximal humerus, but in 120 patients the scapula was involved, and in particular the coracoid part. The latter part would always be included on a chest x-ray; and a sclerotic, expanded coracoid process with coarse trabecu lation should alert one to the possible diagnosis of Paget' s disease. Acrorniocoracoid involement was found to be more common than glenocoracoid dis- ease but both types were associated with pagetoid features of the pelvis and! or skull. As chest radiographs form the largest part of the workload of radiology depart- ments' specific attention should be given to the shoulder girdle, especially in the older patient. Therapeutic implications of estab- hshing a diagnosis of Paget's disease are of definite importance. References 1. Renton P. Pag t's disease. In: Sulton D.A textbook of radiology and imaging, Vol I. Edinburgh: Chur hill Livingstone, 1993 : 79 - 82. 2. Yochum TR & Rowe LJ. Essentials of skeletal radiology, Vow. Baltimore :Williams& Wilk ns, 1987 :865 - 866. 3. Ilamdy Re. Paget's disease of bone : assessmem and management, Eastbome, England: Armour Pharmaceu- tical Company Limited, 1981 :44-49. 4. Barry He. Paget's disease of bone. Edinburgh and Lon- don: E&S Livingstone Ltd, 1969: 42 - 43. 5. Guyer PB & Chamberlain AT Paget's disease of bone in South Africa. Clinical Radiology 1988: 39: 51 - 52.