Orthopaedic Oncology cases Pigmented villous nodular synovitis (PVNS)

A 27-year-old male patient presents to your office for a second opinion. He has

been seen for left knee pain. For the past 6 months, his knee has been episodically swelling and giving him pain, with no antecedent traumatic event. He has had several aspirations which have been bloody. He has already had a diagnostic arthroscopy and was able to biopsy synovial tissue. The patient brings with him the pathology slides from this biopsy (Fig. 8–31).

 

 

 

Figure 8–31

 

What is the patient’s diagnosis?

1. Synovial hemangioma

2. Synovial chondromatosis

3. Rheumatoid arthritis

4. Pigmented villous nodular synovitis (PVNS)

 

Discussion

The correct answer is (D). This patient has PVNS of the knee. Histologic study of the synovium in PVNS on low-power view reveals rounded nodular aggregates and numerous finger-like, villous projections. Higher power reveals diagnostic mononuclear stromal cell infiltrate within the synovium: these cells are round with large nuclei and eosinophilic cytoplasm. There is prominent brown hemosiderin deposition, which differentiates this condition from others associated with synovitis. Hemosiderin-laden macrophages, multinucleated giant cells, and foam cells are also present but not required for diagnosis.

His arthroscopy revealed diffuse PVNS throughout the knee, and further surgery was recommended. He asks your recommendation in terms of treatment. What is the best response?

1. Treatment for diffuse PVNS is aggressive total synovectomy, using arthroscopic, open, or combined arthroscopic/open techniques

2. New chemotherapy regimens have made surgical resection obsolete

3. External beam radiation can be utilized as an alternative treatment to surgery, as PVNS is exquisitely radiosensitive

4. Aggressive synovectomy achieves virtually a zero recurrence rate

 

Discussion

The correct answer is (A). Arthroscopic or open treatment can be pursued for removal of a focal PVNS lesion. The diffuse form requires aggressive total synovectomy using techniques that allow adequate exposure to the anterior and posterior knee; often an open approach is required posteriorly. High rates of recurrence exist, even with extensive synovectomy. Following multiple recurrences, external beam radiation is occasionally used and may lower the risk of further local recurrence. While some biologics are currently in clinical trial stages for PVNS, there is no definitive medical management that replaces surgical synovectomy.

If left untreated, which of the following will occur?

1. Eventual resolution

2. Metastasis

3. Bone and joint erosion and destruction

4. Development in contralateral knee

 

Discussion

The correct answer is (C). PVNS is a benign condition, although a few case reports have documented rare metastatic disease. PVNS is almost exclusively a monoarticular process and is generally not found in more than one joint, even over time. PVNS does not resolve on its own but rather progresses to eventual erosion of the bone and cartilage, with eventual joint destruction.

 

Objectives: Did you learn...?

 

Natural history of PVNS?

 

 

To recognize histologic features of PVNS? Treatment of PVNS?