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MR findings of tuberculous dactylitis: case report
European Journal of Radiology 39 (2001) 163– 167 www.elsevier.com/locate/ejrad
Case report
MR findings of tuberculous dactylitis Chang Jin Yoon a,b, Hye Won Chung a,b, Sung Hwan Hong a,b, Chong Jai Kim c, Heung Sik Kang a,b,* a
Department of Radiology, College of Medicine, Seoul National Uni6ersity, 28 Yongon-Dong, Chongno-Gu, Seoul, 110 -774, South Korea b Department of Radiology, Institute of Radiation Medicine, SNUMRC, Seoul, South Korea c Department of Pathology, College of Medicine, Seoul National Uni6ersity, 28 Yongon-Dong, Chongno-Gu, Seoul, 110 -774, South Korea Received 6 September 2000; received in revised form 23 February 2001; accepted 5 March 2001
Abstract A case of tuberculous dactylitis in an immunocompetent patient is presented and the radiographic findings and differential diagnosis discussed. MR image, although nonspecific, was helpful for differential diagnosis and evaluating the extent of the lesion. Although this is a rare condition, the diagnosis should be considered when dealing with an unusual destructive bony lesion. © 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: MR findings; tuberculous; dactylitis
1. Introduction The skeletal system is the most frequent site of extrapulmonary tuberculosis. Nevertheless, tuberculosis involving the bones of the hand is uncommon, and tuberculous dactylitis is rare. We report a case of tuberculous dactylitis in an 18-year-old immunocompetent patient. To our knowledge, this is the first published report describing the MR findings of this rare entity.
2. Case report A previously healthy 18-year-old male presented with painful swelling and a discharge of pus in the right index finger. Three weeks before, his finger had struck a desk. Physical examination revealed concentric swelling of the affected finger, which was slightly tender on palpation. Yellowish pus was draining through a skin defect in the ulnar side of the finger. Radiographs of the thorax were unremarkable. A radiograph of the hand showed soft * Corresponding author. Tel.: + 82-2-7603217; fax: 7436385. E-mail address: [email protected] (H.S. Kang).
+ 82-2-
tissue swelling and an osteolytic lesion, which was expansile in nature, involving the cancellous bone of the proximal phalanx of the right index finger. The cortex was irregularly thinned with focal destruction at the ulnar side of the phalanx. The bony abnormality was confined to the proximal phalanx without involvement of the interphalangeal joint (Fig. 1A). Radionuclide scanning using Technetium 99 diphosphonate revealed increased uptake of the radioisotope in the affected phalanx. On T2-weighted MR images, the marrow cavity of the affected phalanx was expanded and filled with heterogeneous signal intensity, consisting of a peripheral portion of higher signal intensity and a central portion of relatively low signal intensity. The lesion extended to the soft tissue through the cortical defect forming a sinus tract. Hyperintensity was also noted in the subcutaneous tissue and around the tendon. On T2-weighted images, this same region showed intermediate to low signal intensity on T1-weighted images. With gadolinium contrast imaging, strong rim-like enhancement was noted in the area that was hyperintense on T2-weighted images (Fig. 1B –1E). Owing to the impression of tuberculous dactylitis, an open biopsy and curettage were performed. The histopathologic findings were consistent with tuberculosis,
0720-048X/01/$ - see front matter © 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 7 2 0 - 0 4 8 X ( 0 1 ) 0 0 3 2 7 - 8
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C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
Fig. 1. An 18-year-old man with painful swelling of the right index finger. (A) A radiograph of the hand shows soft tissue swelling and an osteolytic lesion, which is expansile in nature, involving the proximal phalanx of the right index finger. The cortex is irregularly thinned with focal destruction at the ulnar side (arrow). (B) A T2-weighted fast spin-echo MR image (TR/TE, 4000/98), showing the expanded marrow cavity filled with a heterogeneous hyperintense lesion, consisting of higher peripheral and lower central signal intensity. The lesion extrudes through the cortical defect forming a sinus tract that is exposed externally (arrow). (C) In a T1-weighted spin-echo MR image (TR/TE, 500/14), the lesion shows intermediate to low signal intensity (arrow). (D) Gadolinium-enhanced axial image shows strong rim-like enhancement of the lesion (white arrow). Swelling of the soft tissue and hyperintensity in the subcutaneous layer and around the tendon are also noted (black arrow). (E) In a fat suppressed contrast-enhanced coronal image, the lesion extrudes through the cortical defect forming a sinus tract (arrow). The extent of soft tissue involvement is clearly demonstrated as the area of strong enhancement. Compare with the plain radiograph (Fig. 1A).
C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
165
Fig. 1. (Continued)
and the diagnosis of tuberculous dactylitis was confirmed when Mycobacterium tuberculosis grew on tissue culture.
3. Discussion Tuberculosis of the skeleton constitutes 10– 15% of all extrapulmonary tuberculosis. Spinal involvement accounts for half of the cases, while digital involvement account for only 4% [1]. Tuberculous dactylitis is especially frequent in children, although it has also been well-described in adults. Differences between the radiographic appearances of tuberculous dactylitis in children and adults have been observed [2]. In tuberculous
dactylitis of infants and children, the neighboring joint may be spared. There may be sequestration, marked bone expansion, periosteal reaction, bone sclerosis, and sinus formation. Our case fits well with these characteristics, which occur less frequently in adults. Although tuberculous dactylitis can be imitated by other conditions, there are some points helpful for differential diagnosis. Acute pyogenic osteomyelitis has a more rapid course and less frequently extends across the physis or to the neighboring joint than tuberculosis. Syphilitic dactylitis in infants and children produces bilateral symmetric involvement; in this disease, periostitis is more exuberant and soft tissue swelling is less prominent than in tuberculous dactylitis. Sarcoidosis can also mimic tuberculosis, leading to well-demarcated
166
C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
Fig. 1. (Continued)
cystic lesions in the phalanges, although bony expansion and periosteal new bone formation are not found. If a single bone is affected, the possibility of a hemangioma or enchondroma should be considered. In our case, however, clinical symptoms were helpful for excluding the possibility of tumorous conditions. In general, MR imaging has proved to be extremely sensitive in the early detection of osteomyelitis, because of the exquisite contrast it provides between the diseased areas and normal marrow. The infected areas can be seen as regions of decreased signal intensity on T1weighted images, and as regions of increased signal intensity on T2-weighted images. In our case, the T2weighted images showed heterogenous signal intensity, consisting of a rim-like hyperintense portion in the periphery and a relatively decreased signal centrally. The degree of hyperintensity on T2-weighted MR images may provide information about caseous liquefaction. As the cheesy caseum becomes liquid, resulting hyperintensity becomes more conspicuous. Heterogeneity on T2weighted images has been reported to be one of the MR
imaging characteristics of tuberculosis in other sites [3,4]. After intravenous gadolinium administration, strong peripheral rim-like enhancement with clear demarcation of the lesion is evident. This enhancement pattern, although non-specific, is a well-documented finding in both pyogenic and tuberculous abscesses [5,6]. In addition, MR imaging allows evaluation of the extent of the lesion and provides information regarding involvement of the tendon and tendon sheath, as well as disease extension to nearby structures. Cortical destruction with sinus tract formation is also well demonstrated. Our patient had a history of trauma before the swelling developed. This may have been coincidental. However, mild trauma preceding the onset of disease has been reported in more than 20% of cases of skeletal tuberculosis [7]. In summary, although rare, tuberculous dactylitis must be kept in mind when dealing with a lytic expansile lesion that involves a phalanx. MR imaging, although non-specific, may be helpful for differential diagnosis and evaluating the extent of the lesion.
C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
References [1] Martini M, Benkeddache Y, Medjani Y, Gottesmann H. Tuberculosis of the upper limb joints. Int Orthop 1986;10:17 – 23. [2] Feldman F, Auerbach RH, Johnston A. Tuberculous dactylitis in the adults. Am J Rad 1971;112:460 –79. [3] Moon WK, Im JG, Yu IK, Lee SK, Yeon KM, Han MC. Mediastinal tuberculous lymphadenitis: MR imaging appearance with clinicopathologic correlation. Am J Rad 1996;166:21 – 5. [4] Kim TK, Chang KH, Kim CJ, et al. Intracranial tuberculoma:
167
comparison of MR with pathologic findings. Am J Neuroradiol 1995;16:1903 – 8. [5] Paajanen H, et al. Magnetic resonance imaging of local soft tissue inflammation using gadolinium-DTPA. Acta Radiol 1987;28:79 – 82. [6] Kim JY, Park YH, Choi KH, Park SH, Lee HY. MRI of tuberculous pyomyositis. J Comput Assist Tomogr 1999;23:454 – 7. [7] Halsey JP, Reeback JS, Barnes CG. A decade of skeletal tuberculosis. Ann Rheum Dis 1982;41:7 – 10.
Case report
MR findings of tuberculous dactylitis Chang Jin Yoon a,b, Hye Won Chung a,b, Sung Hwan Hong a,b, Chong Jai Kim c, Heung Sik Kang a,b,* a
Department of Radiology, College of Medicine, Seoul National Uni6ersity, 28 Yongon-Dong, Chongno-Gu, Seoul, 110 -774, South Korea b Department of Radiology, Institute of Radiation Medicine, SNUMRC, Seoul, South Korea c Department of Pathology, College of Medicine, Seoul National Uni6ersity, 28 Yongon-Dong, Chongno-Gu, Seoul, 110 -774, South Korea Received 6 September 2000; received in revised form 23 February 2001; accepted 5 March 2001
Abstract A case of tuberculous dactylitis in an immunocompetent patient is presented and the radiographic findings and differential diagnosis discussed. MR image, although nonspecific, was helpful for differential diagnosis and evaluating the extent of the lesion. Although this is a rare condition, the diagnosis should be considered when dealing with an unusual destructive bony lesion. © 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: MR findings; tuberculous; dactylitis
1. Introduction The skeletal system is the most frequent site of extrapulmonary tuberculosis. Nevertheless, tuberculosis involving the bones of the hand is uncommon, and tuberculous dactylitis is rare. We report a case of tuberculous dactylitis in an 18-year-old immunocompetent patient. To our knowledge, this is the first published report describing the MR findings of this rare entity.
2. Case report A previously healthy 18-year-old male presented with painful swelling and a discharge of pus in the right index finger. Three weeks before, his finger had struck a desk. Physical examination revealed concentric swelling of the affected finger, which was slightly tender on palpation. Yellowish pus was draining through a skin defect in the ulnar side of the finger. Radiographs of the thorax were unremarkable. A radiograph of the hand showed soft * Corresponding author. Tel.: + 82-2-7603217; fax: 7436385. E-mail address: [email protected] (H.S. Kang).
+ 82-2-
tissue swelling and an osteolytic lesion, which was expansile in nature, involving the cancellous bone of the proximal phalanx of the right index finger. The cortex was irregularly thinned with focal destruction at the ulnar side of the phalanx. The bony abnormality was confined to the proximal phalanx without involvement of the interphalangeal joint (Fig. 1A). Radionuclide scanning using Technetium 99 diphosphonate revealed increased uptake of the radioisotope in the affected phalanx. On T2-weighted MR images, the marrow cavity of the affected phalanx was expanded and filled with heterogeneous signal intensity, consisting of a peripheral portion of higher signal intensity and a central portion of relatively low signal intensity. The lesion extended to the soft tissue through the cortical defect forming a sinus tract. Hyperintensity was also noted in the subcutaneous tissue and around the tendon. On T2-weighted images, this same region showed intermediate to low signal intensity on T1-weighted images. With gadolinium contrast imaging, strong rim-like enhancement was noted in the area that was hyperintense on T2-weighted images (Fig. 1B –1E). Owing to the impression of tuberculous dactylitis, an open biopsy and curettage were performed. The histopathologic findings were consistent with tuberculosis,
0720-048X/01/$ - see front matter © 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 7 2 0 - 0 4 8 X ( 0 1 ) 0 0 3 2 7 - 8
164
C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
Fig. 1. An 18-year-old man with painful swelling of the right index finger. (A) A radiograph of the hand shows soft tissue swelling and an osteolytic lesion, which is expansile in nature, involving the proximal phalanx of the right index finger. The cortex is irregularly thinned with focal destruction at the ulnar side (arrow). (B) A T2-weighted fast spin-echo MR image (TR/TE, 4000/98), showing the expanded marrow cavity filled with a heterogeneous hyperintense lesion, consisting of higher peripheral and lower central signal intensity. The lesion extrudes through the cortical defect forming a sinus tract that is exposed externally (arrow). (C) In a T1-weighted spin-echo MR image (TR/TE, 500/14), the lesion shows intermediate to low signal intensity (arrow). (D) Gadolinium-enhanced axial image shows strong rim-like enhancement of the lesion (white arrow). Swelling of the soft tissue and hyperintensity in the subcutaneous layer and around the tendon are also noted (black arrow). (E) In a fat suppressed contrast-enhanced coronal image, the lesion extrudes through the cortical defect forming a sinus tract (arrow). The extent of soft tissue involvement is clearly demonstrated as the area of strong enhancement. Compare with the plain radiograph (Fig. 1A).
C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
165
Fig. 1. (Continued)
and the diagnosis of tuberculous dactylitis was confirmed when Mycobacterium tuberculosis grew on tissue culture.
3. Discussion Tuberculosis of the skeleton constitutes 10– 15% of all extrapulmonary tuberculosis. Spinal involvement accounts for half of the cases, while digital involvement account for only 4% [1]. Tuberculous dactylitis is especially frequent in children, although it has also been well-described in adults. Differences between the radiographic appearances of tuberculous dactylitis in children and adults have been observed [2]. In tuberculous
dactylitis of infants and children, the neighboring joint may be spared. There may be sequestration, marked bone expansion, periosteal reaction, bone sclerosis, and sinus formation. Our case fits well with these characteristics, which occur less frequently in adults. Although tuberculous dactylitis can be imitated by other conditions, there are some points helpful for differential diagnosis. Acute pyogenic osteomyelitis has a more rapid course and less frequently extends across the physis or to the neighboring joint than tuberculosis. Syphilitic dactylitis in infants and children produces bilateral symmetric involvement; in this disease, periostitis is more exuberant and soft tissue swelling is less prominent than in tuberculous dactylitis. Sarcoidosis can also mimic tuberculosis, leading to well-demarcated
166
C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
Fig. 1. (Continued)
cystic lesions in the phalanges, although bony expansion and periosteal new bone formation are not found. If a single bone is affected, the possibility of a hemangioma or enchondroma should be considered. In our case, however, clinical symptoms were helpful for excluding the possibility of tumorous conditions. In general, MR imaging has proved to be extremely sensitive in the early detection of osteomyelitis, because of the exquisite contrast it provides between the diseased areas and normal marrow. The infected areas can be seen as regions of decreased signal intensity on T1weighted images, and as regions of increased signal intensity on T2-weighted images. In our case, the T2weighted images showed heterogenous signal intensity, consisting of a rim-like hyperintense portion in the periphery and a relatively decreased signal centrally. The degree of hyperintensity on T2-weighted MR images may provide information about caseous liquefaction. As the cheesy caseum becomes liquid, resulting hyperintensity becomes more conspicuous. Heterogeneity on T2weighted images has been reported to be one of the MR
imaging characteristics of tuberculosis in other sites [3,4]. After intravenous gadolinium administration, strong peripheral rim-like enhancement with clear demarcation of the lesion is evident. This enhancement pattern, although non-specific, is a well-documented finding in both pyogenic and tuberculous abscesses [5,6]. In addition, MR imaging allows evaluation of the extent of the lesion and provides information regarding involvement of the tendon and tendon sheath, as well as disease extension to nearby structures. Cortical destruction with sinus tract formation is also well demonstrated. Our patient had a history of trauma before the swelling developed. This may have been coincidental. However, mild trauma preceding the onset of disease has been reported in more than 20% of cases of skeletal tuberculosis [7]. In summary, although rare, tuberculous dactylitis must be kept in mind when dealing with a lytic expansile lesion that involves a phalanx. MR imaging, although non-specific, may be helpful for differential diagnosis and evaluating the extent of the lesion.
C.J. Yoon et al. / European Journal of Radiology 39 (2001) 163–167
References [1] Martini M, Benkeddache Y, Medjani Y, Gottesmann H. Tuberculosis of the upper limb joints. Int Orthop 1986;10:17 – 23. [2] Feldman F, Auerbach RH, Johnston A. Tuberculous dactylitis in the adults. Am J Rad 1971;112:460 –79. [3] Moon WK, Im JG, Yu IK, Lee SK, Yeon KM, Han MC. Mediastinal tuberculous lymphadenitis: MR imaging appearance with clinicopathologic correlation. Am J Rad 1996;166:21 – 5. [4] Kim TK, Chang KH, Kim CJ, et al. Intracranial tuberculoma:
167
comparison of MR with pathologic findings. Am J Neuroradiol 1995;16:1903 – 8. [5] Paajanen H, et al. Magnetic resonance imaging of local soft tissue inflammation using gadolinium-DTPA. Acta Radiol 1987;28:79 – 82. [6] Kim JY, Park YH, Choi KH, Park SH, Lee HY. MRI of tuberculous pyomyositis. J Comput Assist Tomogr 1999;23:454 – 7. [7] Halsey JP, Reeback JS, Barnes CG. A decade of skeletal tuberculosis. Ann Rheum Dis 1982;41:7 – 10.