Pigmented villonodular synovitis in a rare site

Devaraj Nair; Samson Samuel; SK Varkey; PS John

doi:10.4103/joasis.joasis_3_22

CASE REPORT

Year : 2022 | Volume : 19 | Issue : 1 | Page : 33-35

Pigmented villonodular synovitis in a rare site

Devaraj Nair, Samson Samuel, SK Varkey, PS John
Department of Orthopaedics, Pushpagiri Institute of Medical Science and Research, Thiruvalla, Kerala, India

Date of Submission	09-Feb-2022
Date of Acceptance	08-Mar-2022
Date of Web Publication	26-Jun-2022

Correspondence Address:
Devaraj Nair
Kalladaputhenpurayil House, Thirumoolapuram P.O., Thiruvalla, Pathanamthitta - 689 115, Kerala
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/joasis.joasis_3_22

Abstract

Pigmented villonodular synovitis (PVNS) is a rare locally aggressive benign proliferative growth of the synovium of unknown etiology known to involve the knee (80%), hip (10%), ankle (5%), and exceptionally temporomandibular joint and spine. It poses a diagnostic dilemma when it occurs at the ankle with the clinician tending to overlook it like an ankle sprain or posttraumatic pathology. The optimal treatment is surgery. Malignant change of the lesion, although rare is known for its ability for reactivated growth and a tendency to recur. Postoperative radio synoviorthesis may be required to remove the excess synovium when surgery alone falls short of removing the residual synovial membrane. This article reports the case of a rare localized PVNS of the ankle. Although rare at the ankle, PVNS must neither be mistaken for a malignant lesion nor be neglected as a nonspecific swelling.

Keywords: Ankle, orthopedics, pigmented villonodular synovitis, surgery

How to cite this article:
Nair D, Samuel S, Varkey S K, John P S. Pigmented villonodular synovitis in a rare site. J Orthop Assoc South Indian States 2022;19:33-5

How to cite this URL:
Nair D, Samuel S, Varkey S K, John P S. Pigmented villonodular synovitis in a rare site. J Orthop Assoc South Indian States [serial online] 2022 [cited 2023 Apr 1];19:33-5. Available from: https://www.joasis.org/text.asp?2022/19/1/33/348315

Introduction

Pigmented villonodular synovitis (PVNS) is a rare benign proliferative growth of the synovium of obscure etiology.^[1] It is also known to affect bursae and tendon sheaths. PVNS is typically monoarticular most commonly involving the knee and to a lesser extent the hip, foot, wrist, and ankle to a lesser extent.^[2] The incidence has been cited as the knee (80%), hip (10%), ankle (2.5%–5%), and exceptionally temporomandibular joint and spine.^[3],[4] Growitz and Mankin classified PVNS into two forms – diffuse and localized variety.^[5] These two forms most likely constitute two ends of the gamut of one disease. This difference is noted in the World Health Organization classification, in which DPVNS is termed “diffuse-type giant cell tumor” ICD-O code 9251/0 while LPVNS (intraarticular) and giant cell tumors of tendon sheaths (extraarticular) are coded as 9252/0.^[5] The diffuse variety can erode into adjacent bony areas. In cases of incomplete excision, there is a moderate-to-high recurrence rate for the diffuse PVNS variety.^[6],[7] Therapeutic options range from simple open or arthroscopic synovial tissue excision of localized variety to a much more radical synovectomy.

Case Report

A 60-year-old male, manual laborer, presented with a 3-month-old mechanical type of pain and swelling of the left ankle which was insidious in onset. It was gradually progressive, currently limiting him from going to work. No other history of trauma. The opposite ankle was uninvolved. He gives no history suggestive of polyarthralgia, and there was no contact history with tuberculosis. On clinical examination, a 3 cm × 8 cm doughy nontender swelling with irregular margins is noted on the inferomedial aspect of the medial malleolus [Figure 1] and [Figure 2]. Ankle range of movements, although within normal limits was associated with pain toward a terminal range of motion. The blood routine was found to be within normal limits.

Figure 1: (Medial view) Swelling at inferomedial aspect of the left ankle

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Figure 2: (Posterior view) Swelling at inferomedial aspect of the left ankle

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Radio imaging findings

Tibiotalar subchondral sclerosis and subchondral cyst of talar dome were observed in the left ankle AP view [Figure 3]. T1-weighted (T1W) magnetic resonance imaging (MRI) [Figure 4]a,[Figure 4]b,[Figure 4]c,[Figure 4]d of the left ankle showed a focal well-defined cystic lesion with sclerotic border seen in talar bone on the medial side in subchondral location (20 mm × 12 mm × 7 mm) – not shown on MRI images here. It exhibits low/intermediate signal on T1W, high signal on T2W, and mild enhancement on contrast study. Marked marrow edema noted in talar bone showing enhancement on contrast study. Marked synovial thickening with multiple T2W and T2*W gradients recalled echo hypointense soft tissue nodules (with blooming) seen in anterior and posterior joint space of tibiotalar joint, inferior tibiofibular syndesmosis, and posterior subtalar joints due to hemosiderin deposition. Mild postcontrast synovial enhancement noted. The final opinion was reported as PVNS (localized PVNS) with multiple hemosiderin deposits leading to secondary osteoarthritis of the tibiotalar joint and subchondral cyst.

Figure 3: Radiograph of the left ankle AP and lateral view: subchondral sclerosis. 2. (a) Subchondral cyst (White arrow) – anteromedial aspect of the tibiotalar dome image courtesy: Dr. Amol Gautam (consultant radiologist)

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Figure 4: Magnetic resonance imaging study of the left ankle: (a) Synovial thickening on T1W sagittal sequence in anterior tibiotalar joint space. (b) T2W sagittal sequence exhibits T2W hypointense nodules of focal synovial thickening, (c) Mild enhancing synovium on T1W + C axial image, (d) T2*W GRE coronal image displays marked blooming due to hemosiderin deposition in the synovium image courtesy: Dr. Amol Gautam (consultant radiologist)

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Biopsy

Biopsy [Figure 5] revealed synovial hyperplasia with hemosiderin pigment-laden macrophages and occasional multinucleated giant cells suggestive of chronic synovitis of pigmented villonodular variety.

Figure 5: Open synovial biopsy findings: (1) Synovial hyperplasia. (2) Hemosiderin pigment-laden macrophages. (3) Proliferating capillary-sized vessels with hemosiderin. (4) Foamy macrophages histopathology impression: pigmented villonodular synovitis

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Management

The patient underwent an open partial synovectomy. Surgical exploration revealed a multinodular, red, brown, and thickened synovium with diffuse hemosiderin staining characteristic of PVNS. He is on regular follow-up as an outpatient for the past 8 months. There is no evidence of recurrence.

Discussion

PVNS is an aggressive disease, and there is a substantial incidence of recurrence. When found in the foot and ankle, the large number of joints in this region and limited space make complete excision difficult.^[8] Arthroscopic excision/partial synovectomy may be employed to remove localized variety. Open synovectomy with complete excision is advocated for diffuse variety.

Diagnosing PVNS can be a daunting task, as this master of mimicry successfully eludes detection for even up to 20 years, as reported in the literature.^[9] It may present as asymptomatic swelling or at an arthritic stage with radiological evidence of bone erosions. In the setting of sparse multinucleated giant cells and erratic mitotic cells differentiating PVNS from a malignant pathology can be difficult for the pathologist.^[10] It is interesting to note that according to Loriaut et al., MRI assists in the diagnosis of PVNS due to its ability to show hemosiderin deposits in the joint, demonstrate the localized or diffuse nature of the disease, and reveal any associated lesions.^[11] In the search for newer modalities of treating and preventing a recurrent PVNS growth, especially in the diffuse PVNS variety that has eroded into the joint, radiotherapy or isotopic synoviorthesis has had promising results. Radiation oncologists have been reluctant to employ radiation in the treatment of benign disease for several reasons: (1) the small but not negligible risk of the late appearance of radiation-induced malignant tumors; (2) the need to reduce the radiation dose if an independent neoplasm was to arise in the same region of the body; and (3) nonmalignant tissue changes that might appear subsequently and complicate healing of surgical wounds.^[12] The use of anti-TNF-α has also been recommended. However, its effectiveness is contested.

Conclusion

Although rare at the ankle, PVNS must neither be mistaken for a malignant lesion nor be neglected as a nonspecific swelling.

Acknowledgment

I express my gratitude to the Department of Pathology and Radiology of Pushpagiri Medical College for providing me with the necessary assistance. I thank Dr. Amol Gautam, Consultant Radiologist, Insight Imaging, TMM Hospital, for providing the necessary MRI and X-ray imaging and expert description in relation to them.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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