Six-month-history of pain along the lumbar spine and the right L4 distribution. MRI of the spine was insignificant. MRI of his right hip, however, demonstrated florid synovial osteochondromatosis distorting the capsule and compressing the femoral nerve. Biopsies taken during a synovectomy and hip resurfacing procedure reported the presence of chondrosarcoma.
A 43 year old gentleman referred with a six-month history of pain along the lumbar spine and the right L4 distribution. His family doctor considered it to be a spinal lesion. Clinically he had L4 radicular pain distribution. Coughing and sneezing exacerbated his pain, but he had no other neurological symptoms. In addition, he had Trendlenberg gait and sign. The right hip showed flexed flexion deformity of 10o, flexion of 600 and negligible rotation. There was wasting of quadriceps, but no other motor or sensory deficits. Reflexes and stretch tests were normal apart from a markedly positive right femoral stretch test Analgesia did not provide pain relief, nor did a short course of physiotherapy. MRI of the spine showed mild disc degeneration at L4/5 with no nerve root compression. MRI of his right hip, however, demonstrated florid synovial osteochondromatosis grossly distorting the capsule anteriorly, posteriorly and medially, compressing the femoral nerve within the femoral triangle. The patient was offered synovectomy and a hip resurfacing procedure. Biopsies taken intraoperatively subsequently reported the presence of chondrosarcoma. He is now under specialists in the bone tumour field.
Primary synovial osteochondromatosis is an uncommon benign synovial disorder resulting in multiple calcified intra- and juxta-articular bodies. The monoarticular disorder involves the transformation of synovium into cartilage by proliferation and metaplastic change. Most frequently affected is the knee, followed by the hip, elbow and small joints of the wrist and hands. Clinical diagnosis of synovial osteochondromatosis is difficult. In the early stages of synovial osteochondromatosis, recurrent pain in the affected joint is not associated with radiographic changes. Diagnosis is often made only when these changes manifest themselves and include juxta-articular calcified and/or ossified bodies (the most common finding in the hip), bone erosion, occasional osteoarthritis and regional osteoporosis(1). The unusual presentation of this case makes it particularly interesting. The patient’s acute symptoms were consistent with a right-sided L4 root lesion. He complained of back pain, had nerve root pain, a positive cough impulse, restricted spinal motion, muscle wasting and a positive femoral stretch test. He did not, however, demonstrate any reflex loss or loss of sensation. The patient had examination features attributable to his hip problem including a limp, a fixed flexion deformity, limited flexion and minimal rotation of the hip. The femoral nerve lies lateral to the femoral artery, lying in a groove between the psoas tendon and iliacus. The psoas major tendon lies immediately anterior to the hip capsule as does part of iliacus, with the remainder separated from the capsule by the bursa. These anatomical relations explain how intracapsular pathology may readily produce femoral nerve compression. It also demonstrates the risk to the femoral nerve posed by anterior capsulectomy during total hip replacement. An MRI scan revealed that this patient’s symptoms were due to manifestation of his synovial osteochondromatosis. A literature search reveals that this is a complication of synovial osteochondromatosis of the hip not previously reported. There are reports of nerve compression occurring with synovial osteochondromatosis of the elbow(3,4,11), of the wrist(11) and one interesting case of vertebral facet joint involvement leading to compressive myelopathy(6). In these cases the distance between the affected tissue and affected nerve is much smaller than that of the hip joint. Treatment of synovial osteochondromatosis of the hip involves open/arthroscopic synovectomy and removal of loose bodies. Good long term results after this treatment have been reported(7). If, however, there is associated severe osteoarthritis, total hip replacement is indicated(8). There have been several reported cases of synovial osteochondromatosis progressing to chondrosarcoma, with a series incidence of up to 5%(9,10). Mortality approaches 50%, partly because of the difficulty of early diagnosis(11). This diagnosis should be borne in mind with recurrent presentations of synovial osteochondromatosis and should be suspected when there is a rapid deterioration in the clinical status or with bone involvement detected on MRI.(12) This case demonstrates a novel presentation of synovial osteochondromatosis and secondary chondrosarcoma of the hip. It also emphasises the potential for lower limb pain, produced by localised nerve compression, to mimic radicular pain.
Synovial Osteochondromatosis and Chondrosarcoma Presenting As a Nerve Root Lesion
1. No obvious abnormalities were found on the lumbar MRI; however, the patient's right hip joint MRI shows significant thickening and bulging of the joint capsule area, with multiple irregular cartilaginous or calcified fragment shadows, suggesting “cartilage-like” or “calcification-like” tissue.
2. The lesion is mainly located around the right hip joint, with obvious enlargement of the joint capsule; local soft tissue swelling is observed, compressing adjacent anatomical structures (such as the psoas major tendon, iliacus muscle, etc.).
3. Imaging indicates that the lesion compresses the femoral nerve (located between the psoas major and the iliacus), suggesting that the symptoms (including pain resembling L4 nerve root irritation and proximal muscle strength limitation) are likely related to nerve involvement.
4. Histopathological images (HE staining) indicate proliferation of cartilaginous matrix with a certain degree of cellular atypia, supporting a chondroid tumor. Combined with intraoperative sampling and pathological biopsy, this further confirms malignant transformation or the development of chondrosarcoma.
Based on the patient's symptoms, histopathological results, and imaging findings, the main diagnostic considerations and differential diagnoses are as follows:
Considering the following factors:
1. Imaging: Multiple cartilaginous or calcified densities in and around the right hip joint, with compression of the femoral nerve;
2. Pathology: Biopsy showing cartilage components with varying degrees of malignant cytological features;
3. Clinical Presentation: The patient's pain mimicking L4 nerve root issues but actually due to femoral nerve compression, indicating local mass effect;
4. History: The patient may have had early-stage synovial chondromatosis with subsequent malignant transformation.
In conclusion, the most likely final diagnosis is “Synovial Osteochondromatosis with Secondary Chondrosarcoma” leading to local compression of the femoral nerve.
1. Treatment Strategy:
- Surgical Intervention: Since malignant transformation has occurred and there are evident symptoms of femoral nerve compression, early surgical treatment is recommended. Surgical options may include thorough debridement of the intra-articular lesion, anterior joint capsule resection, and decompression of the femoral nerve. If the articular cartilage is severely damaged, a thorough assessment is needed to determine whether joint reconstruction or total hip arthroplasty is appropriate.
- Adjuvant Therapy: For patients with malignant chondroid tumors, further radiotherapy or chemotherapy may be considered based on tumor staging. However, chondrosarcomas have limited sensitivity to radiotherapy or chemotherapy, so consultation with a specialized bone tumor team is advised.
- Perioperative Management: Emphasize nutritional support and protection of the femoral nerve function, and prevent complications such as thrombosis and infection.
2. Rehabilitation/Exercise Prescription Recommendations:
- Rehabilitation Principles: Gradual progression, individualized approach, ensuring postoperative stability of the surgical site and the recovery of nerve function.
- Early Stage (Postoperative Weeks 1–2):
Disclaimer: This report is a reference analysis based on the provided information and does not replace an in-person diagnosis or professional medical advice. If you have any concerns or if symptoms worsen, please seek medical attention promptly.
Synovial Osteochondromatosis and Chondrosarcoma Presenting As a Nerve Root Lesion
