Latissimus Dorsi Tendinosis and Tear: Imaging Features of a Pseudotumor of the Upper Limb in Five Patients

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1 Pseudotumor of the Upper Limb Musculoskeletal Imaging Clinical Observations Suzanne E. Anderson 1 Ralph Hertel 2 James O. Johnston 3 Edouard Stauffer 4 Eva Leinweber 1 Lynne S. Steinbach 5 Anderson SE, Hertel R, Johnston JO, Stauffer E, Leinweber E, Steinbach LS DOI: /AJR Received August 6, 2004; accepted after revision October 26, Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital of Bern, Inselspital, Freiburgstrasse, CH-3010 Bern, Switzerland. Address correspondence to S. E. Anderson (suzanne.anderson@bluewin.ch). 2 Department of Orthopedics, University Hospital of Bern, Inselspital, Bern, Switzerland. 3 Orthopedic Oncology, The Permanent Medical Group, South San Francisco, CA. 4 Department of Pathology, University Hospital of Bern, Inselspital, Bern, Switzerland. 5 Department of Radiology, University of California, San Francisco, San Francisco, CA. AJR 2005; 185: X/05/ American Roentgen Ray Society Latissimus Dorsi Tendinosis and Tear: Imaging Features of a Pseudotumor of the Upper Limb in Five Patients OBJECTIVE. The objective of our study was to determine the imaging appearances of a pseudotumor of the upper limb, latissimus dorsi tendinosis and tear, in five patients and to correlate those imaging findings with clinical history and histopathology. CONCLUSION. Tears or reactive tendinosis of the latissimus dorsi tendon at its insertion on the proximal humerus may present as a pseudotumor. Awareness of the imaging findings may allow accurate diagnosis and conservative management. he latissimus dorsi tendon may T rarely be avulsed or may undergo degeneration with the clinical and imaging appearances mimicking a tumor of the proximal humerus. The tendon may occasionally undergo degeneration with overuse, such as with playing volleyball, or may be acutely avulsed as a result of rapid adduction of the arm from full elevation, such as with slam-dunking a basketball. Both chronic and acute injuries to this tendon may be mistaken for a tumor both clinically and on MRI. We present five such cases. Materials and Methods Five patients presented between 1998 and 2002 with a provisional clinical diagnosis of sarcoma of the upper limb for further imaging. There were four males and one woman. The age range was 15 to 58 years (mean age, 34.8 years). All patients were right hand dominant. Available images, which included radiographs in five patients (anteroposterior views of the proximal humerus including the shoulder joint and oblique lateral views of the proximal humerus), CT scans in two patients, technetium-99 methylene diphosphonate bone scintigraphy in two patients, and MRI (n = 6) in five patients, were retrospectively reviewed by two radiologists by consensus. Radiographs and CT studies were reviewed for the location of bone fragment avulsion, periosteal reaction or erosion, bone destruction, and presence of a soft-tissue calcification or mass. Bone scintigraphy was reviewed for the presence of focal radionuclide uptake. MRI was performed on a 1.5-T unit (Signa, GE Healthcare) with the following protocol: oblique sagittal and coronal STIR (TR range/te range, 1,040 4,440/14 84), axial T1-weighting ( /12 15), T2-weighting (4,000 5,160/46 84), and STIR (5,300 5,340/13 30) sequences followed by fat-saturated IV gadolinium enhanced T1-weighted sequences in five of six patients in the axial plane ( /12 14) and oblique coronal plane ( /12 14). Axial T2- weighted and STIR sequences are part of the routine tumor protocol, and contrast material was administered also as part of the routine MRI tumor protocol. The T2-weighted images were obtained using fast spin-echo technique and were not fatsuppressed. One patient declined contrast administration. A standard shoulder coil was used for four of five patients with one patient requiring the use of a standard torso coil due to the large size of the associated muscle injury. One patient underwent follow-up MRI 6 months after the initial MRI as part of clinical follow-up. MR images were reviewed by two musculoskeletal radiologists by consensus for location and evidence of altered bone marrow signal intensity or bone destruction; periosteal reaction at the latissimus dorsi tendon insertion site, tendinosis, or tendon tear (defined as a discontinuity of the tendon components); and adjacent soft-tissue reaction or mass. Tendon lesion was defined as any thickening or irregularity to the normal contour of the tendon or any altered signal intensity within the tendon. A bone or soft-tissue mass was defined as a focal region with shape and volume that caused either destruction or displacement of adjacent anatomic structures. Imaging findings were correlated with intraoperative findings (n = 2), histopathologic findings (n = 2), and/or clinical and imaging follow-up (n = 3) of 2 6 years, with an average of 3.8 years. Additional AJR:185, November

2 clinical history was elicited such as sports and occupational history to suggest a possible cause. Results All patients had upper limb shoulder girdle discomfort with mild pain on downward movement of the upper limb. On palpation, diffuse pain was elicited over the proximal medial humeral shaft. The right side was involved in four patients and the left in one patient. Three patients were referred from the orthopedic oncology service and one patient each from the sports medicine clinic and from internal medicine. Results are summarized in Table 1. Three patients retrospectively had sportsrelated injuries. One 15-year-old basketball enthusiast had an acute trauma from slamdunking a basketball. His sports medicine doctor was disturbed by the visible mass at the back of the shoulder and ordered MRI for tumor staging. He did not consider that the reported injury could be related to the tumor. One 17-year-old amateur volleyball player, also a rollerblade-skating enthusiast, had a history of several months of chronic discomfort that had increased after a period of intensive training. He presented with pain in the region of pectoralis major muscle. A 42-yearold patient had a sports history of gymnastics at the Olympic level in vaulting associated with chronic pain and no other history of trauma. He had chronic nonspecific shoulder pain with no history of trauma. The other 42- year-old patient suffered several years of upper limb discomfort not associated with any specific trauma or activity. The oldest patient, who was 58 years old, recalled minor trauma from lifting heavy office furniture several years earlier. Biochemical, hematologic, and infection screening results were normal in all patients, with calcific, inflammatory, and autoimmune disorders and myofascitis being excluded. On radiographs, two patients had evidence of a small radiopacity adjacent to the medial aspect of the humeral diaphysis, 8 10 cm caudal to the superior surface of the humeral head, with one being evident on radiographs obtained 9 years earlier at the time of the minor trauma from lifting office furniture. In TABLE 1: Five Patients with Latissimus Dorsi Tendon Injury Presenting as Pseudotumor Sex Patient Age (yr) Cortical Pit and Soft-Tissue Calcification Seen on Side Clinical Provisional Affected Presentation Diagnosis Radiography CT F 42 Right Several years duration of shoulder pain M 58 Left Previous minor trauma M 15 Right Basketball slamdunking injury M 17 Right Volleyball player with pain in the region of pectoralis major muscle M 42 Right Previous Olympic vaulting gymnast with chronic pain Osteogenic sarcoma Chondrosarcoma or osteoid osteoma Focal Uptake on Bone Scanning Tendinosis Latissimus Dorsi two patients, there was a small region of humeral cortical erosion (Fig. 1). CT showed focal erosion in two patients, and bone scintigraphy showed focal radionuclide tracer uptake at the insertion site corresponding to the latissimus dorsi insertion site on MRI. Review of the patients other radiographs showed no signs of soft-tissue calcification. MRI showed evidence of latissimus dorsi tendinosis in four of five patients as thickening of the tendon with inhomogeneous signal intensity on all sequences and irregularity to its contour (Fig. 1). Three of these patients had subtle morphologic changes of the pectoralis major tendon at its insertion site, and one other patient had evidence of minor alteration within the proximal portion of the teres major tendon with some altered signal intensity on T2 and STIR sequences with some fatty atrophy within the proximal muscle. There was an incomplete tear to the latissimus dorsi tendon in one patient that occurred at its insertion associated with extensive tear and hemorrhage within the latissimus dorsi and teres major muscles (Fig. 2). MRI a Size (cm) of Bone Reaction at Latissimus Dorsi Insertion Site Clinical and Surgical Follow-Up Incisional biopsy of mm and mm masses; tendinosis + b Incisional biopsy of mm mass; tendinosis Sarcoma Normal + c 1.5 Conservative treatment Sarcoma Conservative treatment Sarcoma Conservative treatment Duration of Follow-Up (yr) Note Plus sign (+) means positive findings for both the presence of a cortical pit (focal defect within the humeral cortex) and soft-tissue calcification; minus sign ( ), negative findings. a A mass was not detected on MRI in any of the patients. b Small fragment 9 years earlier. c Muscle hematoma detected on MRI also AJR:185, November 2005

3 Pseudotumor of the Upper Limb A C Fig year-old woman referred from orthopedic oncology with concern for sarcoma with typical imaging appearances of latissimus dorsi tendon injury pseudotumor. Patient had experienced intermittent low-grade pain over upper third of humeral shaft for several years. A, Oblique frontal radiograph shows evidence of cortical erosion (arrowhead) and calcification (arrow). B, Oblique image from bone scan shows focal radionuclide uptake in proximal humerus (arrow). C, Axial T1-weighted MR image shows low-signal-intensity periosteal, cortical, and intramedullary reactions at site of origin of latissimus dorsi tendon (solid arrow) and evidence of fatty atrophy within latissimus dorsi muscle (open arrow). D, Axial contrast-enhanced T1-weighted MR image shows enhancement within latissimus dorsi tendon (arrow) at its insertion site and within cortex and adjacent bone marrow. (Fig. 1 continues on next page) B D In all cases, there was an adjacent cortical reaction and associated characteristic small region of altered bone marrow signal intensity at the level of the tendon insertion (Fig. 3). In four of five patients gadolinium-enhanced MR images showed evidence of contrast enhancement within the latissimus dorsi tendon and within the cortex at the insertion site, in nearby bone marrow, and in adjacent AJR:185, November

4 E Fig. 1 (continued) 42-year-old woman referred from orthopedic oncology with concern for sarcoma with typical imaging appearances of latissimus dorsi tendon injury pseudotumor. Patient had experienced intermittent low-grade pain over upper third of humeral shaft for several years. E, Oblique sagittal STIR image shows radiographic correlate with cortical reaction (arrow) and bone marrow reaction (arrowhead). F, Photomicrograph shows dense reactive connective tissue (arrow) at tendon insertion site consistent with tendinosis. There is evidence of bone remodeling (arrowheads). (H and E, 10) A Fig year-old male basketball player with acute onset of pain and mass formation after slam-dunking who was referred by his sports medicine doctor for sarcoma review. A, Axial T1-weighted MR image shows extensive increased signal intensity within latissimus dorsi muscle (arrows), which is consistent with recent hemorrhage. B, Corresponding axial T2-weighted MR image shows extensive partial tear of latissimus dorsi and teres major tendons (black arrows) and muscle with hemorrhage (white arrow) more posteriorly. soft tissues. There was no focal contrast enhancement to suggest a mass either within soft tissues or bone. Contrast-enhanced images showed increased detail of reaction within the cortex of the humerus at the insertion site of the latissimus dorsi tendon, but did not alter the diagnosis. MRI excluded a tumor and allowed the diagnosis of a pseudotumor in all five patients; however, surgery was performed for histopathologic confirmation in two patients because of the concern of the orthopedic tumor surgeon. In both cases, histopathology excluded a malignant tumor and infection. A diagnosis of reactive tendinosis with reactive bone remodeling was made. Biopsy material consisted of gray dense connective tissue with some adjacent cortex and medullary bone measuring 3 5 cm in one patient and cm in the second patient. The process was found to be centered on the interface of tendon and cortex. There was prominent osteoclastic activity but also focal appositional new bone formation with a marked osteoblastic seam of reaction, and in the center of the specimen, there was evidence of a small residual bone fragment. In F B 1148 AJR:185, November 2005

5 Pseudotumor of the Upper Limb The altered bone marrow findings may dominate the picture with the more subtle tendon findings being overlooked. Radiologists are not routinely used to looking at these ten- Fig year-old male amateur volleyball player and rollerblade enthusiast with upper limb discomfort. Sagittal STIR image shows typical appearance of associated altered bone marrow signal intensity (arrow). adjacent medullary bone, evidence of subtle fibrosis and of some macrophages was seen. However, the dominant picture was that of a chronic fibrotic reaction at the insertion site of the tendon with discontinuity of the cortical bone surface reminiscent of, for example, plantar fascitis of the calcaneus. The other four patients had clinical and radiographic follow-up (one patient with a second MRI examination) for 2 6 years, with an average of 3.8 years; a decrease in symptoms over time; and no evidence of tumor development. Discussion Acute or chronic overuse of the latissimus dorsi tendon may be associated with characteristic MRI findings that may mimic a tumor. These include tendinosis or avulsion of the tendon with irregularity, thickening, and altered signal intensity at its insertion on the proximal humerus that is associated with cortical erosion and a small region of diffuse altered bone marrow signal intensity. This lesion may be misidentified as a tumor if the radiologist does not appreciate the anatomic association of the altered bone marrow signal intensity and cortical reaction with the tendon abnormality. A B Fig. 4 Diagrams and images illustrate anatomy of latissimus dorsi tendon and muscle. A, Diagram from anterior aspect shows insertions of pectoralis major (1), latissimus dorsi (2), and teres major (3) tendons. Bone landmarks include crista tuberculi majoris (arrow), crista tuberculi minoris (arrowhead), and sulcus intertubercularis (asterisk). B, Diagram of posterior aspect shows latissimus dorsi muscle fibers (m), aponeurosis (a), and tendon insertion (2) with adjacent teres major muscle and tendon insertion (3). Tendons of latissimus dorsi and teres major pass posteriorly onto anteromedial aspect of humerus. Components of large spanning latissimus dorsi muscle are evident. Transitional fibers (Tr) pass toward L1 and L2 levels and supraspinous ligaments. Raphe fibers (R) attach to lateral raphae of thoracolumbar fascia (Tf). Iliac fibers (IL) attach to iliac crest (Ic). (Fig. 4 continues on next page) AJR:185, November

6 dons in this region of the shoulder girdle compared with the rotator cuff and anterior shoulder girdle muscles. The overuse may be associated with sporting activities such as basketball, volleyball, and gymnastic vaulting, as was the case in our series, and golfing and water skiing, as previously described in the sports medicine orthopedics literature [1, 2]. There have been two case reports regarding the MRI findings of latissimus dorsi tendon abnormalities in the sports medicine literature [1, 2]. One patient, a 38-year-old male novice golfer with posterior shoulder pain after excessive playing, had radiographs that showed a cortical defect in the proximal humerus and MRI findings that revealed avulsion of the conjoined tendons of latissimus dorsi and teres major [1]. The other patient was a 42-year-old male competitive waterskier who presented with a palpable tender mass in the right posterior axilla several days after a water-skiing injury [2]. On MRI, there was focal increased signal intensity on T2- weighting, approximately 2 cm in width, consistent with complete avulsion of the latissimus dorsi tendon. The latissimus dorsi muscle is a large fanshaped muscle covering the posterolateral aspect of the thorax with extensive attachments on the thoracic, lumbar, and sacral spinous processes with a relatively short linear tendon C Fig. 4 (continued) Diagrams and images illustrate anatomy of latissimus dorsi tendon and muscle. C, Coronal localizer image with axial slice of 41-year-old healthy female volunteer defines level of axial image for D. D, Axial T1-weighted image of 41-year-old healthy female volunteer depicts axial anatomy corresponding to line drawing of A with tendon insertions of pectoralis major (1), latissimus dorsi (2), and teres major (3). attachment to the proximal humerus [3], as shown in Figure 4. Mechanically it is a powerful adductor and extensor of the shoulder. Large adduction forces applied to the fanshaped muscles are transferred to the short tendon inserting on the proximal humerus. This is seen particularly with the arm in full elevation, resulting in partial or complete tear of the tendon. Clinical histories include slam dunking with a basketball, vaulting in gymnastics on a vault table, and downward forceful movements used in volleyball. Dissections of five cadaver and three fresh frozen human specimens have shown that the latissimus dorsi tendon begins posteriorly and then curves inferiorly and anteriorly around the teres major tendons to insert 1 cm anteriorly to the teres major tendon, with the two tendons being joined to one another just proximal to the separate insertion sites on the humerus [4]. This anatomic feature and the different intensities of injuries and mechanism of injury presumably account for the slight variations in the MRI findings in our series. The different intensities of injury and whether there was a single injury or repetitive injury would also explain the associated injuries with the teres major and pectoralis major tendons. Important neurovascular structures are closely associated with the conjoined tendons of latissimus dorsi and teres major including the axillary nerve and posterior humeral circumflex artery superiorly and the radial nerve inferiorly [4]. However, these structures were not injured in the patients in our series, but it is prudent to review these structures in patients with this injury. Other tendon abnormalities of the upper limb have been described as presenting as tumorlike lesions. Cortical desmoidlike lesions of the proximal humerus have been described in gymnasts, ringman s shoulder lesion, associated with overuse of the pectoralis major tendon [5]. Pectoralis major tendon injuries mimicking tumors associated with soft-tissue calcifications have been described [6] with histopathologic evidence of degeneration of the tendon and nonspecific calcifications. Both acute and chronic pectoralis major tendon abnormalities have been shown to be well evaluated with MRI [7, 8]. The latissimus dorsi tendon lesion is similar to the well-described pectoralis major tendon lesion; however, the anatomic site is different with the bone interface and tendon abnormalities being seen adjacent to the proximal humerus in a more medial and posteromedial location. The latissimus dorsi lesion may also be seen slightly more caudal than the pectoralis major lesion. The muscle and adjacent soft-tissue abnormalities that may be associated with the latissimus dorsi D 1150 AJR:185, November 2005

7 Pseudotumor of the Upper Limb lesion are seen in the posterior upper thorax and posterior upper limb region as opposed to the anterior chest wall, as is found with pectoralis major lesions. Both normal and variant insertion site bone pits of the deltoid muscle [9] and chronic avulsive injuries of the deltoid insertion in adolescents mimicking tumors [10] have been described. Softtissue calcifications in the upper limb and shoulder girdle region associated with either trauma and avulsion [11] or calcific deposition, either hydroxyapatite or calcium pyrophosphate [12], remain in the radiologic differential diagnosis. In conclusion, tears or reactive tendinosis of the latissimus dorsi tendon at its insertion on the proximal humerus may present as a pseudotumor. Awareness of the imaging findings may allow accurate diagnosis and conservative management. Acknowledgments Thank you to Klaus Oberli for his anatomical medical illustrations, to Marlese Kaelen for normal anatomy, to Karen Kohli for imaging support, and to Susanne Furrer for final manuscript support. References 1. Spinner RJ, Speer KP, Mallon WJ. Avulsion injury to the conjoined tendons of the latissimus dorsi and teres major tendons. Am J Sports Med 1998; 26: Henry JH, Scerpella TA. Acute traumatic tear of the latissimus dorsi tendon from its insertion. Am J Sports Med 2000; 28: Bogduk N, Johnson G, Spalding D. The morphology and biomechanics of latissimus dorsi. Clin Biomechanics 1998; 13: Beck PA, Hoffer MM. Latissimus dorsi and teres major tendons: separate or conjoint tendons? J Pediatr Orthop 1989; 9: Fulton MN, Albright JP, El-Khoury GY. Cortical desmoid-like lesion of the proximal humerus and its occurrence in gymnasts (ringman s shoulder lesion). Am J Sports Med 1979; 7: Chadwick CJ. Tendinitis of the pectoral major insertion with humeral lesions. J Bone Joint Surg Br 1989; 71: Ohashi K, El-Khoury K, Albright JP, Tearse DS. MRI of complete rupture of the pectoralis major muscle. Skeletal Radiol 1996; 25: Connel DA, Potter HG, Sherman MF, Wickiewicz TL. Injuries of the pectoralis major muscle: evaluation with MR imaging. Radiology 1999; 210: Morgan H, Damron T, Cohen H, Allen M. Pseudotumor deltoideus: a previously undescribed anatomic variant at the deltoid insertion site. Skeletal Radiol 2001; 30: Donnelly LF, Helms C, Bisset GS III. Chronic avulsion injury of the deltoid insertion in adolescents: imaging findings in three cases. Radiology 1999; 211: Bui-Mansfield LT, Taylor DC, Uhrchak JM, Tenuta JJ. Humeral avulsion of the glenohumeral ligament: imaging features and a review of the literature. Am J Radiol 2002; 179: Holt PD, Keats TE. Calcific tendonitis: a review of the usual and unusual. Skeletal Radiol 1993; 22:1 9 AJR:185, November