Synovial Chondromatosis of Dorsal Spine: Case Report of Rare Pathological Entity and Review
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Abstract
Synovial chondromatosis is an uncommon benign condition of metaplastic and focal formation of cartilage in the intimal layer of synovial membrane of joints with extremely low risk of malignant potential. Disease process is typically monoarticular predominantly involving large joints and spinal involvement being a very rare event. We report 31-year-old male patient who presented with history of low backache, left lower limb pain, difficulty in micturition since 8 months and difficulty in walking since 2 months .Magnetic resonance imaging of spine revealed D10-11 extradural lesion arising from left facet joint. Lesion was excised completely by posterior approach with resolution of symptoms. Literature reveals fourteen cases of spinal variant of synovial chondromatosis which has been published and this report represents the fifteenth case.
INTRODUCTION
Synovial chondromatosis (SC) is a rare monoarticular pathological entity of unknown origin diagnosed on pathological confirmation characterised by synovial proliferation and metaplasia, resulting in multiple intra-articular cartilaginous loose bodies in the synovium of joint producing mechanical symptoms. The disease process involves calcification or ossification of cartilaginous nodules in the joint and extrude to the loose bodies in the joint space or extra-articular extension into soft tissue1234). Compression on bone and nerves is caused by calcified or ossified bodies and can cause bone erosion or pain on movement or even at rest5691112). Including this current description, there are fifteen cases of spinal SC reported in medical literature 1517) (Table 1).
CASE REPORT
Thirty-one-year-old male patient presented with history of low backache with left lower limb pain, difficulty in micturition since 8 months and difficulty in walking due to tightness of lower limbs since 2 months. Left lower limb pain intensity recorded on a visual analogue scale was of seven points. Neurological examination revealed, muscle strength of grade II in left lower limb and grade III in right lower limb according to British Medical Research Council grading. Patient had grade 3 spasticity (modified Ashworth scale), exaggerated deep tendon reflexes in left lower limb with normal sensory component and extensor plantar reflexes in both lower limbs. Haematological work up was normal. Magnetic resonance imaging (MRI) of spine revealed an extradural lesion at D10-D11 arising from left facet joint, lesion was hypo to isointense on T1 and T2 MRI sequence with conus compression; on gadolinium injection minimum peripheral enhancement was seen (Fig. 1).
Patient was planned for elective surgery and underwent dorsal hemilaminectomy of D10, D11, and D12 with removal of facet joints at involved level followed by total excision of firm to hard tumour. Histopathology revealed fragments of bone, disc and cartilage with a lesion composed of chondriod nodules having chondrocytes in clusters. Chondrocytes showed hyperchromatic nuclei and binucleation with one fragment of tissue showing vascularised lining resembling synovium. No mitotic activity and necrosis was suggesting typical features of SC(Fig. 2). At follow-up of 3 weeks, patient was pain free, reduction of spasticity to grade 1 with restoration of normal daily activities and better bladder control was present.
DISCUSSION
SC is a benign metaplastic pathological entity rather than a neoplastic one, in which nodules are formed from aggregates of chondrocytes in the synovium which is the cause for patient's mechanical symptoms17). SC of the spine is an extremely rare disease which has been reported only in series of case reports. Among those cases, cervical spine was the most frequent site of involvement till 201018).
SC can be divided into primary and secondary forms. Primary SC represents a benign idiopathic neoplastic disease process and secondary SC is associated with joint abnormalities like arthritic or mechanical conditions that can lead to intra-articular chondral bodies10). The median age at the time of presentation of vertebral SC is 39 years (range, 21 to 60 years), and the male to female ratio is approximately 1:1. Pain was the most common presenting symptom in 9 patients and other symptoms included a growing mass, weakness and paraesthesia15). Definitive preoperative diagnosis of SC is exceedingly difficult and challenging due to the nondescript clinical presentation and vague characteristic profile of imaging14918). Clustered chondrocytes show varying nuclear polymorphism, binucleate cells, increased mitotic activity, and prominent cellularity are seen microscopically716). Thus preoperatively it is diagnosis of exclusion and definitive confirmative diagnosis is often made postoperatively after analysing microscopic features. Characteristic typically calcified or osseous bodies are seen on plain radiography, however calcification may not be seen in 5% to 30% of cases because of the lack of matrix mineralization, those had appeared as water-dense foci. Computed tomography scan typically reveals a soft-tissue mass with multiple calcifications. MRI reveals nodules are seen using an intermediate to isointense signal on T1 sequences, high signal intensities on T2 sequences and enhancement after gadolinium administration1913). Due to malignant transformation risk with recurrence of approximately 6% to 17%, inferred from extra-vertebral SC, recommended treatment is surgery which includes removal of the loose body or mass and the complete synovectomy of the affected joints which is highly effective in alleviating the symptoms. Although the recurrence rate is very low in vertebral SC, it is thought that recurrence is secondary to incomplete removal of synovial lining and no agreed treatment guideline is available. Arthrodesis has been reported to be a successful as a salvage treatment option for recurrent SC and in case instability is suspected78131416).
CONCLUSION
To summarize it is a benign uncommon pathology entity without any definitive preoperative diagnostic features. Surgery is the definitive treatment and confirmation by histology which should be considered as gold standard. Complete resection prevents recurrence.
Notes
CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported.