Pediatric and Developmental Pathology 17, 221-225, 2014 DOI: 10.2350/14-02-1445-CR. 1 © 2014 Society fo r Pediatric Pathology
Synovial Chondromatosis of the Cervical Spine: A Case Report and Review of the Literature A
ndrew
and
S h a w , 1,2 Z io n Z ib l y , 2 V
in a y
P r a s a d , 3 D a n ie l I k e d a , 1,2 D a n ie l B o u e , 3
L a n c e S. G o v e r n a l e 1,2*
1Division o f Pediatric Neurosurgery, Nationwide Children's Hospital, 555 South 18th Street, Columbus, OH 43205, USA d e p a rtm e n t o f Neurosurgery, Ohio State University, 410 West 10th Avenue, Columbus, OH 43210, USA d e p a rtm e n t o f Pathology, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
Received February 27, 2014; accepted March 20, 2014; published online March 20, 2014.
A B S TR A C T
Synovial chondromatosis is a benign condition charac terized by metaplastic changes of the synovial membrane typically affecting large joints. Cervical spine involve ment is rare and has not been reported in a teenager. The authors report a case of cervical synovial chondromatosis in a 19-year-old male presenting with left-sided weakness and numbness from spinal cord compression. After gross total resection was accom plished via laminoplasty, the patient’s presenting symp toms improved and continued to do so over the follow-up period. The likely cause of the synovial chondromatosis in this patient was repetitive neck trauma as a child from a motor vehicle accident and football. This case demonstrates that the pathophysiology of this rare entity can initiate in the pediatric population. Although rare, synovial chondromatosis should be considered in the differential diagnosis of calcified extradural masses in the teenage population. Key words: cervical spine, facet joint, spinal cord compression, synovial chondromatosis
IN T R O D U C T IO N
Synovial chondromatosis (SC) is a benign condition characterized by metaplastic change within the synovial membrane resulting in the formation of multiple carti laginous nodules within the synovium [1,2]. These nodules can then calcify or ossify resulting in extrusion from the synovium leaving loose bodies within the joint space or extraarticular soft tissues [3]. Synovial chon dromatosis typically affects large joints, such as the knees, hips, and elbows, but has been reported to involve the facet joints in the spine. Paravertebral SC is extremely uncommon, with only 9 cases reported in the literature but never in the teenage population [1,2,4-9], Here we *Corresponding author, e-mail: [email protected]
present a case of SC in a cervical facet joint presenting with hemiparesis in a teenage male. CASE REPORT
A previously healthy 19-year-old male presented to our institution with 6 months of left arm and leg weakness and numbness. He also reported neck pain and 2 episodes of a sensation of urinary retention without incontinence of bladder or bowel. He played collegiate football and was involved in an automobile collision 2 years prior to presentation. Examination revealed 4 of 5 strength in the left arm and leg with numbness in the same distribution. He had a normal postvoid residual. Imaging revealed an extradural mass adjacent to the left C3-C4 facet with spinal cord compression (Fig. 1). The mass showed peripheral enhancement and heavy calcification but no erosion of the surrounding bone. The patient underwent a C3 laminoplasty for gross total resection of the mass. The mass was white and had a firm consistency like rubber. It was separable from the bone and facet and was removed en bloc. The dura and nerve roots were not incorporated into the mass. The immediate postoperative course was uncompli cated, and there was no new neurologic deficit. As of the 12-month follow up, the patient’s strength was much improved with 4+ (very close to 5) of 5 strength in the left arm and leg. His numbness improved as well with only slight residual. There were no bladder or bowel problems. He had residual neck pain that required further symp tomatic treatment. His overall function dramatically improved, and he returned to college. Imaging showed no residual or recurrent mass. Pathologic findings
Gross pathologic examination revealed a smooth-sur faced, thin, solid-white cartilage cap overlying an internal shiny, pale, tan-brown area of endochondral ossification (Fig. 2A). Hematoxylin and eosin stain showed thickened, lobulated proliferations of hyaline cartilage, composed of
Figure 1. Coronal m agnetic resonance and co m p ute d to m o g ra p h ic images o b ta in e d p rio r to surgery. Left: A T 2-w eighted im age d e m o n stra tin g a large m ixed h ypo/hyper intense lesion on th e le ft a t th e C3-C4 level. Spinal cord compression and edema are present. Center: A T 1-w eig hte d p o stg a d o lin iu m im age sh ow ing p eripheral enhancem ent. R ight: A bonew in d o w e d co m p ute d to m o g ra p h ic im age revealing heavy ca lcifica tion b u t no erosion o f th e su rro u n d in g bone. A color version o f th is fig u re is available o nline.
disorganized spherical accumulations of chondroid matrix with haphazard slightly hypercellular clusters of proliferating chondrocytes, focally incorporating appar ent entrapped ligamentum flavum, which appears as fibroelastic type tissue (Fig. 2B). The chondrocyte nuclei were variably enlarged and pleomorphic, at least mildly atypical but overall reactive appearing (Fig. 2C,D). There were no mitoses and no definite binucleate chondrocytes seen. No necrosis was present. Scant hypocellular medullary spaces showed only relatively bland spindle cells, and no invasion of bone was seen. There was extensive underlying endochondral ossifica tion. These features were overall consistent with primary SC with extensive underlying endochondral ossifica tion. There was no evidence of chondrosarcomatous transformation. DISCUSSION
Synovial chondromatosis is a benign condition that involves metaplasia of the synovial membrane resulting in the formation of cartilaginous nodules that may calcify or ossify. The nodules may float in the joint space or extrude into the extra-articular soft tissues. There is an extremely low risk of malignancy with SC, but case reports have described the coexistence of chondrosarcoma with SC [10]. Typically, SC affects the large joints. Knees are most commonly involved and account for 60%-70%
222
A. S haw
et al .
of cases; the elbow, hip, and shoulder are other common sites [3,11], The male to female ratio is 2 to 1. Synovial chondromatosis typically affects patients with a mean age of 40-45 years old [8,11,12]. Paravertebral SC is extremely uncommon, with only 9 cases reported in the literature but never in the teenage population [1,2,4-8]. A summary of these cases is presented in Table 1. The median age at time of treatment was 35.5 years old with a male to female ratio of 1 to 1. Of the 9 patients in the literature plus our present case, 7 presented with pain, 5 with weakness, 5 with sensory changes, 2 with joint swelling, and 2 with tenderness to palpation. The distribution of spinal level was 45% cervical, 45% thoracic, and 10% lumbar, with 1 patient presenting with a cervico-thoracic lesion and 1 with a costotransverse joint lesion. Synovial chondromatosis can be divided into primary and secondary forms. Primary SC is considered to be benign reactive metaplasia of the synovium without inciting joint pathology [3,13]. Milgram and colleagues divided it into 3 phases. Phase 1 encompasses active synovial disease without loose bodies [13]. Phase 2 involves a transitional phase with osteochondral nodules in the synovium and free floating in the joint space. Phase 3 demonstrates multiple free osteochondral bodies with intrasynovial disease [13]. Secondary SC is more common and occurs in the setting of preexisting joint
Figure 2. P athologic images o f th e surgical specimen. A. A p h o to o f th e gross specimen a fte r bisection. It consists o f an o u te r sm ooth, th in , s o lid -w h ite ca rtilag e "c a p ” and an in n e r shiny, pale, ta n -b ro w n area o f e nd och on dra l ossification. B. An H&E-stained section sh ow ing th e resemblance o f th e lesion to an o steo cartilag ino us exostosis (o rig in a l m a g n ific a tio n x 50). C. An H&E-stained section d e m o n stra tin g th a t th e lesion is com posed o f extensive e nd och on dra l ossification. The section also shows m ic ro n o d u la r aggregates o f chondrocytes a t th e lo w e r rig h t co rn er (o rig in a l m a g n ific a tio n X100). D. An H&Estained section sh ow ing clusters o f chondrocytes. The nuclei are va riab le and show considerable v a ria tio n in size (o rig in a l m a g n ific a tio n X200).
pathology, such as osteoarthritis, osteonecrosis, neuropathic osteoarthropathy, osteochondral fractures, tuberculosis, or rheumatoid arthritis [2,3,14]. The underlying joint pathol ogy results in free chondral or osteochondral fragments that implant into the synovium, inducing metaplastic change in the cartilage around them [3], The exact pathogenesis remains unclear but is most likely secondary to metaplasia in the synovium with differentiation of resting fibrocytes into fibroblasts, chondrocytes, and cartilage [2], High levels of bone morphogenic protein types 2 and 4 have been implicated in the pathobiology of cartilaginous and osteogenic metaplasia seen in SC [15], Recurrence rates in extraspinal disease have been reported as high as 15% [11], As a result of the disease’s potential for recurrence and malignant degeneration, extraspinal surgical treatment involves complete syno vectomy of the involved joint with removal of loose bodies [11,13,14], Radiographically, these lesions image
as soft-tissue masses with multiple calcifications; how ever, 5%-30% of cases may not have calcification [8,14]. On magnetic resonance imaging, they are typically isointense to intermediate on T1 sequences and have high signal intensities on T2-weighted sequences with enhancement following gadolinium administration. In our case, the lesion was mixed in its appearance on magnetic resonance imaging with areas of T2 hyperintensity mixed with foci of T2 hypointensity. On T l, the lesion had isointense areas mixed with hypointense areas. The computed tomographic image did reveal large foci of calcification, as would be expected in these lesions. Due to the rarity of this condition, much of the management has been inferred from extraspinal disease. Because of recurrence rates, resection of the synovium and loose bodies is recommended [2,14]. In our case, the lesion was well circumscribed and was dissectible from the thecal sac medially and facet laterally without Synovial C hondromatosis
223
Table 1.
Summary of reports of spinal synovial chondromatosis
A uthor, year
Age (year), sex
Coscia and 31, F colleagues [6]
Milchgrub and 32, M colleagues [9]
Burrafato and 31, F colleagues [1]
Birchall and 60, M colleagues [4]
Kyriakos and 39, F colleagues [8]
Greenlee and 48, M colleagues [7] Chiba and 52, F colleagues [5]
Gallia and 46, M colleagues [2]
224
A. Shaw et al .
P resenting sym ptom s
2-year history of back pain and tenderness on palpation
Im aging findings
T reatm ent
O utcom e
Resection of the XR: calcified Symptom resolution lesion thoracospinal mass CT: calcified area extending from T4 to T7 Slow-growing painless XR: calcified mass Resection of the Symptom resolution neck mass at site of over costovertebral joint lesion and adjacent previous trauma, bone CT: calcified mass ipsilateral extremity with osteolytic and weakness osteoblastic changes Painful swelling in the XR: multiple Resection of the Resolution of pain right paravertebral calcifications at L4 apophyseal joint of with an improved region for 2 years CT: mass with range of motion of the L4-L5 lumbar vertebrae and the mass the lumbar spine multiple calcifications 6-week history of MRI: irregular, T3 to T5 laminectomy Full recovery after gradually increasing surgery and resection of lobulated extradural weakness and mass centered at T4-T5 extradural mass related to numbness in the legs with associated pressure the T4-T5 facet joint erosion of the posterior aspect of the T5 vertebral body. The lesion demonstrated T1 isointensity, T2 hyperintensity, and an associated syrinx from T6 to T9 9-month history of XR: subtle lucency in Hemilaminectomy of Residual neck pain worsening constant caused by instability the lamina and spinous C3 and partial facetectomy of C3-C4, at C4-C5, no neck, bilateral shoulder, process of C3 CT: lucent lesion abnormal synovial and bilateral arm pain neurologic change filling and expanding tissue resected from with numbness and the medullary space within the facet joint paresthesia in the left hand of the C3 spinous process MRI: foraminal narrowing at C3-C4 and C5-C6, intermediate T1 and high T2 signal lesions in the spinous process of C3 and in the lamina of C3 and C4 1-year history of arm MRI: T2 hyperintense Corpectomy and Relief of pain mass arising at C4-C5 facetectomy for weakness, pain, and diminished dexterity resection disc space Facetectomy, C7 3-month history of Symptoms improved CT: spur formation, laminectomy and enlargement, and severe arm pain, mild irregularity of the weakness of distal resection of the epidural mass C7-T1 facet joint with muscles epidural extension MRI: mass at the C7 epidural space with mild cord compression 4-year history of neck Two-stage procedure: Relief of symptoms CT: calcified mass at C1-C2 extending to the C1-C2 laminoand shoulder pain, facetectomy, resection limited range of motion skull base and spinal of the epidural mass, canal and partial resection of MRI: mass at C1-C2 C2 vertebral body with involvement of followed by anterior C2 vertebral body resection of the residual mass and Cl arch
Table 1.
Continued
A u thor, year
Present report
Age (year), sex
P resenting sym ptom s
Im aging findings
T reatm ent
22, F
Neck pain, partial Brown-Sequard syndrome
C2-C5 laminoRelief of symptoms facetectomy and fusion
19, M
6 months of left arm and leg weakness and numbness, neck pain, and 2 episodes of a sensation of urinary retention
XR: lateral osseous abnormality at C2 ring MRI: enhancing intraspinal mass displacing the spinal cord MRI: extradural mass adjacent to left C3-C4 facet with spinal cord compression; mass T1 isointense with areas of hypointensity, T2 areas of hyper- and hypo-intensity, peripheral enhancement CT: heavy calcification of the mass, no bone erosion
C3 laminoplasty for gross total resection of the mass
O utcom e
Significant improvement in strength and sensation with minimal residual weakness and numbness; some residual neck pain; no bladder or bowel problems
XR indicates radiography; CT, computed tomography; MRJ, magnetic resonance imaging.
evidence o f residual disease. During the follow-up period, the patient’s presenting symptoms improved. He will be followed with serial radiography to evaluate for potential recurrence, which is less likely after gross total resection.
CONCLUSION Synovial chondromatosis is a rare, typically benign condition that may involve the synovial facet joints of the spine and can result in neurologic deficits. Here we report a case o f this disorder involving the cervical spine o f a teenage patient. The likely cause o f SC in this patient was repetitive neck trauma as a child from motor vehicle accident and football. This case demonstrates that the pathophysiology of this rare entity can initiate in the pediatric population. Despite the fact there have been no reported recurrences of SC in the spine, serial radiography is still recommended due to the extraspinal recurrence rate and the overall paucity of reported cases. Gross total resection o f the mass with involved synovium may further reduce the risk of recurrence. Synovial chondromatosis should be included in the differential diagnosis of calcified extradural masses in the teenage population. ACKNOW LEDGMENT
We acknowledge the expert assistance in pathologic consultation o f Dr Michael J. Klein, The Hospital for Special Surgery, New York, NY. REFERENCES 1. Burrafato V, Campanacci DA, Franchi A, Capanna R. Synovial chondromatosis in a lumbar apophyseal joint. Skeletal Radiol 1998; 27:385-387.
2. Gallia GL, Weiss N, Campbell JN, McCarthy EF, Tufaro AP, Gokaslan ZL. Vertebral synovial chondromatosis: report o f two cases and review of the literature. J Neurosurg Spine 2004; 1:211-218. 3. Villacin AB, Brigham LN, Bullough PG. Primary and secondary synovial chondrometaplasia: histopathologic and clinicoradiologic differences. Flum Pathol 1979; 10:439^451. 4. Birchall D, Khangure MS, Spagnolo DV. Vertebral synovial osteochondromatosis with compressive myelopathy. Spine 1999; 24:921-923. 5. Chiba S, Koge N, Oda M, et al. Synovial chondromatosis presenting with cervical radiculopathy: a case report. Spine 2003;28:E396E400. 6. Coscia MF, Edmonson AS, Pitcock JA. Paravertebral synovial osteochondromatosis: a case report. Spine 1986; 11:82-87. 7. Greenlee JD, Ghodsi A, Baumbach GL, VanGilder JC. Synovial chondromatosis o f the cervical spine: case illustration. J Neurosurg 2002;97:150. 8. Kyriakos M, Totty WG, Riew KD. Synovial chondromatosis in a facet joint o f a cervical vertebra. Spine 2000;25:635-640. 9. Milchgrub S, Mulhollan T, Vuitch MF, Wheatherall PT. Case report 692: synovial chondrometaplasia of the 1st costovertebral joint. Skeletal Radiol 1992;21:45M8. 10. Hermann G, Abdelwahab IF, Klein M, Kenan S, Lewis M. Synovial chondromatosis. Skeletal Radiol 1995;24:298-300. 11. Davis RI, Hamilton A, Biggart JD. Primary synovial chondroma tosis: a clinicopathologic review and assessment of malignant potential. Hum Pathol 1998;29:683-688. 12. Mussey RD, Jr, Henderson MS. Osteochondromatosis. J Bone Joint SurgA m 1949;31A:619-627. 13. Milgram JW. Synovial osteochondromatosis: a histopathological study of thirty cases. J Bone Joint Surg Am 1977;59:792-801. 14. Crotty JM, Monu JU, Pope TL, Jr. Synovial osteochondromatosis. Radiol Clin North Am 1996;34:327-342. 15. Nakanishi S, Sakamoto K, Yoshitake H, Kino K, Amagasa T, Yamaguchi A. Bone morphogenetic proteins are involved in the pathobiology of synovial chondromatosis. Biochem Biophys Res Commun 2009;379:914-919.
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Synovial Chondromatosis of the Cervical Spine: A Case Report and Review of the Literature A
ndrew
and
S h a w , 1,2 Z io n Z ib l y , 2 V
in a y
P r a s a d , 3 D a n ie l I k e d a , 1,2 D a n ie l B o u e , 3
L a n c e S. G o v e r n a l e 1,2*
1Division o f Pediatric Neurosurgery, Nationwide Children's Hospital, 555 South 18th Street, Columbus, OH 43205, USA d e p a rtm e n t o f Neurosurgery, Ohio State University, 410 West 10th Avenue, Columbus, OH 43210, USA d e p a rtm e n t o f Pathology, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
Received February 27, 2014; accepted March 20, 2014; published online March 20, 2014.
A B S TR A C T
Synovial chondromatosis is a benign condition charac terized by metaplastic changes of the synovial membrane typically affecting large joints. Cervical spine involve ment is rare and has not been reported in a teenager. The authors report a case of cervical synovial chondromatosis in a 19-year-old male presenting with left-sided weakness and numbness from spinal cord compression. After gross total resection was accom plished via laminoplasty, the patient’s presenting symp toms improved and continued to do so over the follow-up period. The likely cause of the synovial chondromatosis in this patient was repetitive neck trauma as a child from a motor vehicle accident and football. This case demonstrates that the pathophysiology of this rare entity can initiate in the pediatric population. Although rare, synovial chondromatosis should be considered in the differential diagnosis of calcified extradural masses in the teenage population. Key words: cervical spine, facet joint, spinal cord compression, synovial chondromatosis
IN T R O D U C T IO N
Synovial chondromatosis (SC) is a benign condition characterized by metaplastic change within the synovial membrane resulting in the formation of multiple carti laginous nodules within the synovium [1,2]. These nodules can then calcify or ossify resulting in extrusion from the synovium leaving loose bodies within the joint space or extraarticular soft tissues [3]. Synovial chon dromatosis typically affects large joints, such as the knees, hips, and elbows, but has been reported to involve the facet joints in the spine. Paravertebral SC is extremely uncommon, with only 9 cases reported in the literature but never in the teenage population [1,2,4-9], Here we *Corresponding author, e-mail: [email protected]
present a case of SC in a cervical facet joint presenting with hemiparesis in a teenage male. CASE REPORT
A previously healthy 19-year-old male presented to our institution with 6 months of left arm and leg weakness and numbness. He also reported neck pain and 2 episodes of a sensation of urinary retention without incontinence of bladder or bowel. He played collegiate football and was involved in an automobile collision 2 years prior to presentation. Examination revealed 4 of 5 strength in the left arm and leg with numbness in the same distribution. He had a normal postvoid residual. Imaging revealed an extradural mass adjacent to the left C3-C4 facet with spinal cord compression (Fig. 1). The mass showed peripheral enhancement and heavy calcification but no erosion of the surrounding bone. The patient underwent a C3 laminoplasty for gross total resection of the mass. The mass was white and had a firm consistency like rubber. It was separable from the bone and facet and was removed en bloc. The dura and nerve roots were not incorporated into the mass. The immediate postoperative course was uncompli cated, and there was no new neurologic deficit. As of the 12-month follow up, the patient’s strength was much improved with 4+ (very close to 5) of 5 strength in the left arm and leg. His numbness improved as well with only slight residual. There were no bladder or bowel problems. He had residual neck pain that required further symp tomatic treatment. His overall function dramatically improved, and he returned to college. Imaging showed no residual or recurrent mass. Pathologic findings
Gross pathologic examination revealed a smooth-sur faced, thin, solid-white cartilage cap overlying an internal shiny, pale, tan-brown area of endochondral ossification (Fig. 2A). Hematoxylin and eosin stain showed thickened, lobulated proliferations of hyaline cartilage, composed of
Figure 1. Coronal m agnetic resonance and co m p ute d to m o g ra p h ic images o b ta in e d p rio r to surgery. Left: A T 2-w eighted im age d e m o n stra tin g a large m ixed h ypo/hyper intense lesion on th e le ft a t th e C3-C4 level. Spinal cord compression and edema are present. Center: A T 1-w eig hte d p o stg a d o lin iu m im age sh ow ing p eripheral enhancem ent. R ight: A bonew in d o w e d co m p ute d to m o g ra p h ic im age revealing heavy ca lcifica tion b u t no erosion o f th e su rro u n d in g bone. A color version o f th is fig u re is available o nline.
disorganized spherical accumulations of chondroid matrix with haphazard slightly hypercellular clusters of proliferating chondrocytes, focally incorporating appar ent entrapped ligamentum flavum, which appears as fibroelastic type tissue (Fig. 2B). The chondrocyte nuclei were variably enlarged and pleomorphic, at least mildly atypical but overall reactive appearing (Fig. 2C,D). There were no mitoses and no definite binucleate chondrocytes seen. No necrosis was present. Scant hypocellular medullary spaces showed only relatively bland spindle cells, and no invasion of bone was seen. There was extensive underlying endochondral ossifica tion. These features were overall consistent with primary SC with extensive underlying endochondral ossifica tion. There was no evidence of chondrosarcomatous transformation. DISCUSSION
Synovial chondromatosis is a benign condition that involves metaplasia of the synovial membrane resulting in the formation of cartilaginous nodules that may calcify or ossify. The nodules may float in the joint space or extrude into the extra-articular soft tissues. There is an extremely low risk of malignancy with SC, but case reports have described the coexistence of chondrosarcoma with SC [10]. Typically, SC affects the large joints. Knees are most commonly involved and account for 60%-70%
222
A. S haw
et al .
of cases; the elbow, hip, and shoulder are other common sites [3,11], The male to female ratio is 2 to 1. Synovial chondromatosis typically affects patients with a mean age of 40-45 years old [8,11,12]. Paravertebral SC is extremely uncommon, with only 9 cases reported in the literature but never in the teenage population [1,2,4-8]. A summary of these cases is presented in Table 1. The median age at time of treatment was 35.5 years old with a male to female ratio of 1 to 1. Of the 9 patients in the literature plus our present case, 7 presented with pain, 5 with weakness, 5 with sensory changes, 2 with joint swelling, and 2 with tenderness to palpation. The distribution of spinal level was 45% cervical, 45% thoracic, and 10% lumbar, with 1 patient presenting with a cervico-thoracic lesion and 1 with a costotransverse joint lesion. Synovial chondromatosis can be divided into primary and secondary forms. Primary SC is considered to be benign reactive metaplasia of the synovium without inciting joint pathology [3,13]. Milgram and colleagues divided it into 3 phases. Phase 1 encompasses active synovial disease without loose bodies [13]. Phase 2 involves a transitional phase with osteochondral nodules in the synovium and free floating in the joint space. Phase 3 demonstrates multiple free osteochondral bodies with intrasynovial disease [13]. Secondary SC is more common and occurs in the setting of preexisting joint
Figure 2. P athologic images o f th e surgical specimen. A. A p h o to o f th e gross specimen a fte r bisection. It consists o f an o u te r sm ooth, th in , s o lid -w h ite ca rtilag e "c a p ” and an in n e r shiny, pale, ta n -b ro w n area o f e nd och on dra l ossification. B. An H&E-stained section sh ow ing th e resemblance o f th e lesion to an o steo cartilag ino us exostosis (o rig in a l m a g n ific a tio n x 50). C. An H&E-stained section d e m o n stra tin g th a t th e lesion is com posed o f extensive e nd och on dra l ossification. The section also shows m ic ro n o d u la r aggregates o f chondrocytes a t th e lo w e r rig h t co rn er (o rig in a l m a g n ific a tio n X100). D. An H&Estained section sh ow ing clusters o f chondrocytes. The nuclei are va riab le and show considerable v a ria tio n in size (o rig in a l m a g n ific a tio n X200).
pathology, such as osteoarthritis, osteonecrosis, neuropathic osteoarthropathy, osteochondral fractures, tuberculosis, or rheumatoid arthritis [2,3,14]. The underlying joint pathol ogy results in free chondral or osteochondral fragments that implant into the synovium, inducing metaplastic change in the cartilage around them [3], The exact pathogenesis remains unclear but is most likely secondary to metaplasia in the synovium with differentiation of resting fibrocytes into fibroblasts, chondrocytes, and cartilage [2], High levels of bone morphogenic protein types 2 and 4 have been implicated in the pathobiology of cartilaginous and osteogenic metaplasia seen in SC [15], Recurrence rates in extraspinal disease have been reported as high as 15% [11], As a result of the disease’s potential for recurrence and malignant degeneration, extraspinal surgical treatment involves complete syno vectomy of the involved joint with removal of loose bodies [11,13,14], Radiographically, these lesions image
as soft-tissue masses with multiple calcifications; how ever, 5%-30% of cases may not have calcification [8,14]. On magnetic resonance imaging, they are typically isointense to intermediate on T1 sequences and have high signal intensities on T2-weighted sequences with enhancement following gadolinium administration. In our case, the lesion was mixed in its appearance on magnetic resonance imaging with areas of T2 hyperintensity mixed with foci of T2 hypointensity. On T l, the lesion had isointense areas mixed with hypointense areas. The computed tomographic image did reveal large foci of calcification, as would be expected in these lesions. Due to the rarity of this condition, much of the management has been inferred from extraspinal disease. Because of recurrence rates, resection of the synovium and loose bodies is recommended [2,14]. In our case, the lesion was well circumscribed and was dissectible from the thecal sac medially and facet laterally without Synovial C hondromatosis
223
Table 1.
Summary of reports of spinal synovial chondromatosis
A uthor, year
Age (year), sex
Coscia and 31, F colleagues [6]
Milchgrub and 32, M colleagues [9]
Burrafato and 31, F colleagues [1]
Birchall and 60, M colleagues [4]
Kyriakos and 39, F colleagues [8]
Greenlee and 48, M colleagues [7] Chiba and 52, F colleagues [5]
Gallia and 46, M colleagues [2]
224
A. Shaw et al .
P resenting sym ptom s
2-year history of back pain and tenderness on palpation
Im aging findings
T reatm ent
O utcom e
Resection of the XR: calcified Symptom resolution lesion thoracospinal mass CT: calcified area extending from T4 to T7 Slow-growing painless XR: calcified mass Resection of the Symptom resolution neck mass at site of over costovertebral joint lesion and adjacent previous trauma, bone CT: calcified mass ipsilateral extremity with osteolytic and weakness osteoblastic changes Painful swelling in the XR: multiple Resection of the Resolution of pain right paravertebral calcifications at L4 apophyseal joint of with an improved region for 2 years CT: mass with range of motion of the L4-L5 lumbar vertebrae and the mass the lumbar spine multiple calcifications 6-week history of MRI: irregular, T3 to T5 laminectomy Full recovery after gradually increasing surgery and resection of lobulated extradural weakness and mass centered at T4-T5 extradural mass related to numbness in the legs with associated pressure the T4-T5 facet joint erosion of the posterior aspect of the T5 vertebral body. The lesion demonstrated T1 isointensity, T2 hyperintensity, and an associated syrinx from T6 to T9 9-month history of XR: subtle lucency in Hemilaminectomy of Residual neck pain worsening constant caused by instability the lamina and spinous C3 and partial facetectomy of C3-C4, at C4-C5, no neck, bilateral shoulder, process of C3 CT: lucent lesion abnormal synovial and bilateral arm pain neurologic change filling and expanding tissue resected from with numbness and the medullary space within the facet joint paresthesia in the left hand of the C3 spinous process MRI: foraminal narrowing at C3-C4 and C5-C6, intermediate T1 and high T2 signal lesions in the spinous process of C3 and in the lamina of C3 and C4 1-year history of arm MRI: T2 hyperintense Corpectomy and Relief of pain mass arising at C4-C5 facetectomy for weakness, pain, and diminished dexterity resection disc space Facetectomy, C7 3-month history of Symptoms improved CT: spur formation, laminectomy and enlargement, and severe arm pain, mild irregularity of the weakness of distal resection of the epidural mass C7-T1 facet joint with muscles epidural extension MRI: mass at the C7 epidural space with mild cord compression 4-year history of neck Two-stage procedure: Relief of symptoms CT: calcified mass at C1-C2 extending to the C1-C2 laminoand shoulder pain, facetectomy, resection limited range of motion skull base and spinal of the epidural mass, canal and partial resection of MRI: mass at C1-C2 C2 vertebral body with involvement of followed by anterior C2 vertebral body resection of the residual mass and Cl arch
Table 1.
Continued
A u thor, year
Present report
Age (year), sex
P resenting sym ptom s
Im aging findings
T reatm ent
22, F
Neck pain, partial Brown-Sequard syndrome
C2-C5 laminoRelief of symptoms facetectomy and fusion
19, M
6 months of left arm and leg weakness and numbness, neck pain, and 2 episodes of a sensation of urinary retention
XR: lateral osseous abnormality at C2 ring MRI: enhancing intraspinal mass displacing the spinal cord MRI: extradural mass adjacent to left C3-C4 facet with spinal cord compression; mass T1 isointense with areas of hypointensity, T2 areas of hyper- and hypo-intensity, peripheral enhancement CT: heavy calcification of the mass, no bone erosion
C3 laminoplasty for gross total resection of the mass
O utcom e
Significant improvement in strength and sensation with minimal residual weakness and numbness; some residual neck pain; no bladder or bowel problems
XR indicates radiography; CT, computed tomography; MRJ, magnetic resonance imaging.
evidence o f residual disease. During the follow-up period, the patient’s presenting symptoms improved. He will be followed with serial radiography to evaluate for potential recurrence, which is less likely after gross total resection.
CONCLUSION Synovial chondromatosis is a rare, typically benign condition that may involve the synovial facet joints of the spine and can result in neurologic deficits. Here we report a case o f this disorder involving the cervical spine o f a teenage patient. The likely cause o f SC in this patient was repetitive neck trauma as a child from motor vehicle accident and football. This case demonstrates that the pathophysiology of this rare entity can initiate in the pediatric population. Despite the fact there have been no reported recurrences of SC in the spine, serial radiography is still recommended due to the extraspinal recurrence rate and the overall paucity of reported cases. Gross total resection o f the mass with involved synovium may further reduce the risk of recurrence. Synovial chondromatosis should be included in the differential diagnosis of calcified extradural masses in the teenage population. ACKNOW LEDGMENT
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