Downloaded from www.ajronline.org by 148.251.232.83 on 04/11/18 from IP address 148.251.232.83. Copyright RRS. For personal use only; all rights reserved Robert Ortega 1 David P. Fessell 1 Jon. Jacobson 1 John Lin 1,2 Marnix T. van Holsbeeck 1 Curtis W. Hayes 1 Received June 26, 2001; accepted after revision December 12, 2001. Presented at the annual meeting of the merican Roentgen Ray Society, Washington, DC, May 2000. 1 Department of Radiology, University of Michigan Hospitals, 1500 E. Medical Center Dr., nn rbor, MI 48109-0326. ddress correspondence to D. P. Fessell. 2 Valley Radiology, Ltd., 5322 W. Northern ve., Glendale, Z 85301. 3 Department of Radiology, Henry Ford Hospital, 2799 W. Grand lvd., Detroit, MI 48202. JR 2002;178:1445 1449 0361 803X/02/1786 1445 merican Roentgen Ray Society Original Report Sonography of nkle Ganglia with Pathologic Correlation in 10 Pediatric and dult Patients OJECTIVE. We describe the sonographic imaging characteristics of ankle ganglia with pathologic correlation in 10 patients. CONCLUSION. Foot and ankle ganglia exhibit a spectrum of sonographic appearances from round and completely anechoic masses to hypoechoic, multilobulated, multiseptated masses with dependent debris. ll the ganglionic cysts examined in our study showed posterior acoustic enhancement without solid nodules on sonography. S onography is increasingly being used for assessment of foot and ankle abnormalities. Ganglionic cysts are the most common soft-tissue masses in the foot and ankle [1]. These cysts can be asymptomatic or associated with symptoms such as pain, weakness, swelling, osseous erosion, joint impairment, or tarsal tunnel syndrome [2]. Using sonography, radiologists can rapidly and efficiently diagnose a cystic ankle mass and distinguish it from a solid or complex mass that may require further evaluation. In addition, sonography can reveal the extent of a ganglionic cyst and its relationship to the surrounding structures and can show an origin from a specific joint or tendon. This report illustrates the sonographic appearance of ankle ganglionic cysts with pathologic correlation in 10 patients. To our knowledge, this report is the first sonographic description of a series of ankle ganglionic cysts with pathologic correlation. Materials and Methods database search identified 1,234 consecutive reports of musculoskeletal sonographic examinations of the lower extremity (below the knee) between pril 1995 and May 2000 from one institution, and another database search of a separate institution s records identified 361 additional consecutive reports of foot and ankle sonographic examinations between ugust 1996 and July 2000. These reports were individually assessed to determine whether surgery on the foot or ankle was subsequently performed. ll cases in which a mass lesion was surgically resected were noted and correlated with the pathology report, which yielded 10 cases of pathologically proven ankle ganglia. Institutional review board approval was obtained for this study from both institutions. Sonographic examinations were performed (model HDI 3000 or 5000, dvanced Technology Laboratories, othell, W; or model 5200, coustic Imaging, Phoenix, Z) using linear array transducers ranging from 7.5 to 12 MHz. Sonography was performed by one of seven radiologists experienced in musculoskeletal sonography. Sonograms from the 10 cases were retrospectively evaluated by consensus of three radiologists for the following sonographic characteristics of the mass: echogenicity; posterior acoustic enhancement; and presence or absence of septations, lobulation, or a solid soft-tissue component. Hypoechoic was defined as less echogenic than surrounding muscle with diffuse low-level echoes within the lesion. nechoic was defined as sonolucent except for linear septations. From the original sonography reports, the sonographic diagnosis was noted as well as any communication with a specific joint or tendon. The original report was used because more information is available to the sonographer during real-time scanning than is contained in the static images available for retrospective review. JR:178, June 2002 1445
Ortega et al. Downloaded from www.ajronline.org by 148.251.232.83 on 04/11/18 from IP address 148.251.232.83. Copyright RRS. For personal use only; all rights reserved The size of each mass and thickness of any septations were retrospectively measured by one radiologist. Measurements were made using cursor measurements on the film or manual calipers. The use of Doppler evaluation was also noted from the sonograms and sonography reports. Operative reports were available in seven cases (70%), and the origin of any communicating neck found at surgery was noted. Interpretation of the original pathologic specimens was performed by one of nine pathologists. ll 10 patients were female; patient age at surgery ranged from 12 to 60 years (mean, 39 years). The time between sonography and surgery ranged from 1 to 377 days (mean, 69 days). Results The retrospective consensus interpretations of the sonographic characteristics of the 10 cases are summarized in Table 1. The sonographic and pathologic features are illustrated TLE 1 a Dependent echogenic debris was noted. in Figures 1 5. The ganglionic cysts were anechoic in eight (80%) of the 10 cases (Figs. 1 3 and 5) and hypoechoic in two (20%) (Fig. 4); all 10 showed posterior acoustic enhancement. The two ganglionic cysts that were characterized as hypoechoic were at the anechoic end of the hypoechoic spectrum. Five of the 10 masses had septations (Figs. 2, 3, and 5), and three of the 10 masses had lobulated borders (Figs. 2, 3, and 4). No solid nodules were definitely identified by the consensus review, and none were reported in the original sonography reports. One of the masses had an echogenic dependent component, consistent with dependent debris (Fig. 5). Color Doppler evaluation was performed in four of the 10 cases. No evidence of internal blood flow was noted in any of the masses. No Doppler waveforms were obtained. The size of the ganglionic cysts in the greatest dimension ranged from 0.6 to 4.0 Sonographic Characteristics of Pathologically Proven nkle Ganglia in 10 Patients Location Size (cm) Echogenicity Posterior coustic Enhancement Septations Lobulation Solid Nodules cm. The maximal thickness of any septation was 2 mm. In six of the 10 patients, a history of pain associated with the mass was noted. The preoperative sonography reports provided the diagnosis of a ganglion cyst in seven of the 10 cases. In the remaining three cases, the findings were described as compatible with a ganglion, ganglion cyst versus synovial cyst, and synovial cyst. Compared with the surgical findings, the sonography report correctly identified the source of a communicating neck to a joint in two cases and the absence of any neck in one case (Table 1). In two cases, sonography failed to detect a communication that was noted at surgery, and in two additional cases, sonography suggested the communication originated from a different joint or tendon than was noted at surgery. In three cases, no surgical report was available. Sonographic Origin Surgical Origin Dorsal 0.7 1.2 1.2 nechoic Present bsent bsent bsent No duct visualized Tibiotalar joint Medial 2.3 1.2 1.1 nechoic Present Present Present bsent Posterior tibial tendon or flexor digitorum longus Posterior tibial tendon Posterior 2.5 1.5 1.0 nechoic Present bsent bsent bsent Subtalar joint No data Dorsal 3.0 1.2 2.5 nechoic Present Present Present bsent Talonavicular joint Subtalar joint Medial 1.6 1.7 1.0 nechoic Present Present bsent bsent Questionable communication with posterior tibial nerve No data Dorsal 3.4 1.2 4.0 nechoic Present Present bsent bsent a No duct visualized No duct visualized Dorsal 3.0 1.0 2.4 Hypoechoic Present bsent bsent bsent Subtalar joint Subtalar and tibiotalar joint Lateral 0.6 0.3 0.6 nechoic Present bsent bsent bsent No duct visualized Calcaneocubiod joint and sinus tarsi Dorsal 1.2 0.7 0.3 Hypoechoic Present bsent bsent bsent No duct visualized No data Lateral 1.9 0.5 0.8 nechoic Present Present Present bsent Questionable communication with fifth tarsometatarsal joint Peroneus longus Fig. 1. 29-year-old woman with mass in anterolateral soft tissues of right ankle who presented with increasing pain of 3 months duration., Longitudinal sonogram shows anechoic mass within subcutaneous tissue. No communication with joint or tendon was identified. Posterior acoustic enhancement (arrowheads) can be seen. Reverberation artifact is visible at superficial border of cyst (small arrows). Large arrow = ganglion cyst., Photomicrograph of ganglionic cyst shows dense fibrous wall (arrows) surrounding well-defined central cavity (asterisk). (H and E, 2) 1446 JR:178, June 2002
Downloaded from www.ajronline.org by 148.251.232.83 on 04/11/18 from IP address 148.251.232.83. Copyright RRS. For personal use only; all rights reserved Sonography of nkle Ganglia Fig. 2. 48-year-old woman with mass in lateral soft tissues of ankle., Longitudinal sonogram shows anechoic mass (arrows) with septation (arrowhead)., Photomicrograph of mass shows portion of dense fibrous wall (arrowheads) with myxoid degeneration (arrows) that surrounds central cystic cavity (asterisk). (H and E, 10) Fig. 3. 47-year-old woman with mass in medial soft tissues of right ankle who presented with progressive pain and swelling over 7 months., Longitudinal sonogram shows anechoic mass (arrows) superficial to posterior tibial tendon (small arrowheads) and flexor digitorum longus tendon (large arrowhead)., Transverse sonogram shows anechoic mass (arrows) with lobulation, extending between posterior tibial tendon (small arrowheads) and flexor digitorum longus tendon (large arrowhead). Fig. 4. 42-year-old woman with mass on dorsal ankle., Longitudinal sonogram shows mass (arrows) judged to be hypoechoic relative to surrounding muscle by consensus review. Posterior acoustic enhancement is noted as increased hyperechogenicity of talar cortex (arrowheads). Two split screens were aligned for extended field of view in this image. tib = tibial cortex, talus = talar cortex., Transverse sonogram shows hypoechoic mass with communication (straight arrows) extending toward lateral subtalar joint (curved arrow) between talus (tal) and calcaneus (cal). JR:178, June 2002 1447
Ortega et al. Downloaded from www.ajronline.org by 148.251.232.83 on 04/11/18 from IP address 148.251.232.83. Copyright RRS. For personal use only; all rights reserved Pathology reports were available in all cases. Pathologic findings showed thin-walled cysts containing mucoid material with adjacent mucinous degeneration, which is characteristic of ganglionic cysts. Neither evidence of a synovial lining or solid nodules nor findings of malignancy were noted in the pathology reports. Discussion Soft-tissue masses around the foot and ankle are frequently caused by a cystic mass. Ganglionic cysts are thought to result from focal myxomatous degeneration of collagenous tissue or from a communication with a joint or tendon. Ganglionic cysts are typically contain a viscous, gelatinous fluid that is surrounded by a wall composed of a dense, fibrous connective tissue [1]. Lower extremity ganglionic cysts account for an estimated 15 20% of all ganglionic cysts [1]. Foot and ankle ganglionic cysts account for approximately 70% of all surgically treated lower extremity ganglionic cysts. Compared with wrist ganglia, ankle ganglia are more frequently symptomatic [3]; these ganglia may be symptomatic more often because of their larger average size relative to wrist ganglia. s noted in this report and prior studies, foot and ankle ganglia are typically 1 3 cm versus less than 1.5 cm for most wrist ganglia [4, 5]. Prior reports of sonography of ankle ganglia have included case reports, one of which included pathologic correlation [4]. In contrast, wrist ganglia have been studied extensively with sonography, including several reports with pathologic correlation [5 8]. Ganglia have been reported to be anechoic or hypoechoic in the wrist [6, 9], which is consistent with our findings for ankle ganglia. Reverberation artifact, which produces linear echoes at the superficial border of a ganglionic cyst (Fig. 1), should not be mistaken for internal echoes. Reverberation can be eliminated with the use of a standoff pad or copious amounts of coupling gel. Wrist ganglia have been described as typically well-defined, round, or oval cysts with smooth or lobulated borders [5, 7]. Lobulated borders were noted in three cases in our study (30%) and can be prominent (Figs. 3 and 4). Visualization of a communication with a joint or tendon increases the confidence for the diagnosis of a ganglionic cyst and aids surgical planning [8] (Fig. 4). Ganglionic cysts typically show posterior acoustic enhancement, as did all the ganglia in this report. Small ganglionic cysts, however, may show little or no enhanced through-transmission. If a ganglionic cyst is located adjacent to cortical bone, posterior acoustic enhancement may not be visualized in the tissues deep in relation to the mass [6]. However, in such cases increased through-transmission can be noted as increased hyperechogenicity of the underlying cortex (Fig. 4). ngulation of the transducer can also project the posterior enhancement away from the cortex, which aids visualization. Septations within ganglionic cysts have not been commonly described in wrist ganglia [5 8]. However, septations are frequently observed in ankle ganglia, as evidenced by five ganglia (50%) in our study. Septations can be multiple and branching (Fig. 5). It has been suggested that if septations are noted within soft-tissue masses especially multiple or thick septations, then suspicion for a malignant process should be increased [10]. In four of our cases, there was a discrepancy between the sonographic and surgical findings Fig. 5. 32-year-old woman with mass in anterolateral soft tissues of ankle., Longitudinal sonogram shows anechoic mass (between cursors) with multiple internal septations (arrows)., Transverse sonogram shows mass (large straight arrows) with prominent thick septation (small straight arrow). Echogenic component (curved arrow) can be seen along deep border, which is consistent with dependent debris. TRNSV = transverse, MED = medial aspect of mass. regarding the presence of a duct or its origin from a specific joint or tendon (Table 1). These discrepancies were likely caused by one or more of the following factors: incomplete sonographic evaluation that did not detect a neck or duct that could have been visualized with sonography; the presence of an extremely thin or fibrosed duct that was imperceptible with sonography; or the presence of a duct that dissected deep in a region where multiple joints or tendon s are present, thus causing confusion as to the exact source. Complete evaluation of the mass with careful attention to the detection of a joint or tendon communication can aid diagnosis. When a duct dissects deep in a region of multiple joints or tendons, caution in attributing the exact source is warranted. If the duct does not contain fluid, as may be the case with a fibrosed or scarred duct, then the likelihood of visualization with sonography is decreased. The differential diagnosis of a ganglionic cyst includes anechoic or hypoechoic masses. Common anechoic or hypoechoic masses of the foot and ankle include abscesses, seromas, or hypoechoic lipomas. Clinical history and aspiration can aid in the diagnosis of an abscess. seroma can be indistinguishable from a ganglionic cyst. lipoma can be confirmed with MR imaging. variety of benign and malignant masses can appear hypoechoic. Some solid masses with a homogenous cellular composition, such as neurofibromas and melanomas, can appear hypoechoic with increased through-transmission, simulating a debrisfilled cyst [11, 12]. In cases in which gray-scale imaging does not enable definitive diagnosis of a ganglionic cyst, Doppler assessment can aid evaluation. 1448 JR:178, June 2002
Sonography of nkle Ganglia Downloaded from www.ajronline.org by 148.251.232.83 on 04/11/18 from IP address 148.251.232.83. Copyright RRS. For personal use only; all rights reserved Doppler evaluation was used in four (40%) of 10 of the patients in this retrospective study and was helpful in detecting internal blood flow and defining adjacent vessels. Internal blood flow on Doppler evaluation or the presence of a nodular component raises suspicion for a malignant neoplasm. In such cases, MR imaging, biopsy, or resection can be used to further evaluate the cyst. peripheral, dependent, linear, echogenic component was seen in one of the 10 cases and likely was caused by dependent debris. Dependent debris can obscure a nodule. Imaging the patient in a new position can shift the location of dependent debris and exclude this possibility. There are several limitations to this retrospective report. The study is composed of a relatively small number of cases. The inclusion of only pathologically verified cases is a bias; however, pathologic proof is the strongest gold standard and is needed to establish the sonographic appearance with the highest accuracy. ll 10 patients in this study were female. However, the appearance of wrist ganglia has not been shown to significantly differ for female versus male patients; moreover, a sex difference in the appearance of ankle ganglia would not be expected. The sonographic characteristics of the ankle ganglia were determined by a consensus of three radiologists who were not blinded to the findings from the pathologic specimens, and interobserver variability was not calculated. Surgical reports were available in seven of the 10 cases, which limits the correlation between sonography and surgery for the origin of a communicating neck. Variability in the scanning technique of the sonographers and variability in the interpretation of the surgical specimens by the pathologists are also limitations. This study does not attempt to determine the accuracy of sonography for the detection of ankle ganglia. It is unknown whether there were sonographic false-positive or false-negative cases during the time period included in this study. In conclusion, foot and ankle ganglia exhibit a spectrum of sonographic appearances from round and completely anechoic masses to hypoechoic, multilobulated, multiseptated masses with dependent debris. ll ganglionic cysts showed posterior acoustic enhancement without solid nodules. References 1. Rozbruch SR, Chang V, ohne WH, Deland JT. Ganglion cysts of the lower extremity: an analysis of 54 cases and review of the literature. Orthopedics 1998;21:141 148 2. Steiner E, Steinbach LS, Schnarkowski P, Tirman PFJ, Genant HK. Ganglia and cysts around joints. Radiol Clin North m 1996;34:395 425 3. Kliman EK, Frieberg. Ganglion of the foot and ankle. Foot nkle Int 1982;3:45 46 4. Wu KK. Ganglions of the foot. J Foot nkle Surg 1993;32:343 347 5. Osterwalder JJ, Widrig R, Stober R, Gachter. Diagnostic validity of ultrasound in patients with persistent wrist pain and suspected occult ganglion. J Hand Surg m 1997;22:1034 1040 6. Hoglund M, Tordai P, Muren C. Diagnosis of ganglions in the hand and wrist by sonography. cta Radiol 1994;35:35 39 7. Paivansalo M, Jalovaara P. Ultrasound findings of ganglions of the wrist. Eur J Radiol 1991;13: 178 180 8. De Flavis L, Nessi R, Del o P, Calori G, alconi G. High-resolution ultrasonography of wrist ganglia. J Clin Ultrasound 1987;15:17 22 9. Cardinal E, uckwalter K, raunstein EM, Mih D. Occult dorsal carpal ganglion: comparison of US and MR imaging. Radiology 1994; 193:259 262 10. Ma LD, McCarthy EF, luemke D, Frassica FJ. Differentiation of benign from malignant musculoskeletal lesions using MR imaging: pitfalls in MR evaluation of lesions with a cystic appearance. JR 1998;170:1251 1258 11. Lin JL, Jacobson J, Hayes CW. Sonographic target sign in neurofibromas. J Ultrasound Med 1999;18:513 517 12. Nazarian LN, lexander, Kurtz, et al. Superficial melanoma metastases: appearances on gray-scale and color Doppler sonography. JR 1998;170:459 463 JR:178, June 2002 1449