A 70-year-old female was referred by her primary care provider to the orthopedic clinic for assessment of a mass that had been present in the left cubital fossa for 4 months. Within the past 2 weeks, the mass had become “more painful and larger in size.” She complained of pain and numbness that had gone down to her fingertips, but the pain went away “for a little while.” The patient denied trauma or other serious injury to the area. Her past medical history was significant for hypertension and elevated cholesterol levels. Her surgical history included a hysterectomy at an unspecified date, knee surgery 5 years prior to this presentation, and radial head resection during childhood to treat a comminuted fracture.
Physical examination confirmed that the elbow was swollen and tender. A palpable mass measuring 9 cm wide × 6 cm long was located in the cubital fossa of the left arm. A firm fluctuation was detected on palpation. The mass was nonpulsatile. On visual inspection, the lesion had a dark hue resembling a venous malformation. The radial pulse was palpable. Percussion over the mass elicited a positive Tinel sign, with resultant dysesthesia radiating along the median nerve distribution. The Tinel sign was also positive over the carpal tunnel and the Guyon canal and minimally so over the cubital tunnel. Intrinsic function was normal. The patient had full extension and 130° of flexion in the elbow. Thenar muscle function, as well as wrist flexion and extension, were normal.
The differential diagnosis for a soft-tissue nodular mass is extensive. MRI is useful for narrowing the list to giant cell tumor (GCT) of the tendon sheath, low-grade atypical infection, complex cystic mass (hypertrophic synovitis), bicipital bursitis, trauma (hemorrhagic synovitis), soft-tissue sarcoma or metastatic tumor, fibromatosis, synovial chondromatosis, and pigmented villonodular synovitis (PVNS). In this case, MRI revealed distention of the bicipital radial bursa by fluid with an internal hypointense signal and absence of the radial head. As the MRI (Figure 1A and B) was not definitively diagnostic, surgical intervention was required to establish the final diagnosis and treatment plan. The radiologist reported “fluid distending the bicipital radial bursa that has internal hypointense signal, characteristic of a complex bursitis, likely related to some internal hypertrophic synovitis.” The biceps, brachialis, and triceps muscles and the common extensor and common flexor tendons were intact. The annular and lateral ulnar collateral ligaments were not well seen. A small joint effusion was observed.
The patient was scheduled for excision of the mass. During the procedure, an encapsulated mass was found attached to the distal biceps tendon. No rupture of the biceps tendon was apparent, but the pathologist reported “some hemosiderin attached synovitic-type tissue, which was invasive into the tendon itself.” On removal, the mass was found to be hemorrhagic and had the appearance of a pigmented villonodular synovitic-type process. Pathology reported that the specimen consisted of multiple tan-purple portions of tissue that measured, in aggregate, 3.0 × 3.0 × 1.5 cm. The PVNS finding was checked multiple times by the pathologist because of its unusual location.
Pigmented villonodular synovitis, an idiopathic proliferative disorder, is rare, with an incidence of 1.8 cases per million population.1 Research regarding the epidemiology of PVNS is limited because it is so rare, especially in the elbow. In 2009, Wyatt and colleagues stated that fewer than 20 cases of PVNS in the elbow had been reported in the literature.2 This finding is consonant with a 1999 article that identified only 12 published cases.3
PVNS is a benign proliferation of synovial cells and mesenchymal supporting tissue that is typically found in synovial joints and tendons that are enclosed with sheaths.4 The disorder can take on either a localized/nodular or a diffuse form.4 The diffuse form is monoarticular and found in the knee; hip; ankle; and, rarely, the elbow.2 The localized form is found in the tendons of the digits and needs to be differentiated from a GCT of the tendon sheath. The knee is the most common site of PVNS in both the localized/ nodular and the diffuse forms, accounting for 80% of reported cases.4,5 Clinical experience has shown that when PVNS occurs in the upper extremity, it most commonly affects the flexor tendons of the wrist. The similar condition of GCT is reported to affect both flexor and extensor tendons of the digits.6 According to Hegedus and Theresa, the localized form most frequently affects the tendon sheaths of the hands and feet.5 The characteristics of the mass in this case were consistent with the localized/nodular form of PVNS, although the location of either form on the biceps tendon is extremely rare. Which form of PVNS could be expected to affect the biceps tendon has yet to be determined.
Etiology of PVNS remains uncertain, although it has been deemed a benign process.7 Mankin and colleagues suggest a potiental neoplastic origin based on studies of the diffuse form, which have identified clonal abnormalities.7 PVNS tumors may be painless in early stages, and progression is typically slow. Pain is, however, the most common presenting symptom.4 Other common presenting symptoms include swelling and limited range of motion (ROM). The severity and type of ROM limitation depends, partly, on which form of PVNS is present. Diffuse forms often manifest with symptoms that mimic those of arthritis, whereas localized forms may present with mechanical symptoms, including locking or catching in the affected joint.5 In as many as 50% of cases, the lesion invades bone, leading to osteoarticular changes. Bone invasion is more common in the diffuse form than in the localized/nodular form and more common for tumors in the knee, hip, and foot. Lesions of the hip often destroy the femoral head and the acetabulum.7 Another possible complication of PVNS is chronic arthralgia, which disrupts activities of daily living and puts patients at greater risk of complications secondary to a more sedentary lifestyle.
A literature search for published cases similar to the one presented here found only one other article on PVNS in the biceps tendon. The 1999 article was originally published in Italian in the journal, Casistica Clinico-Radiologica,8 and we were unable to obtain a translation. Nevertheless, the image in the article showed that the mass was in the proximal biceps tendon near the shoulder. Otherwise, the majority of publications on PVNS relate to the knee.
Treatment for the localized form of PVNS usually comprises arthroscopic or open synovectomy, which has a reasonable prognosis with regard to recurrence.3 In the more common PVNS locations, open excision is recommended.7 Optimal treatment of PVNS in the elbow or the biceps tendon is less certain.
Treatment options for the diffuse form of PVNS vary, and no single treatment is preferred. Combined arthroscopic synovectomy and low-dose radiation therapy are often utilized, as recurrence is more common in the diffuse form.4 If the diffuse form is present, Mankin and colleagues recommend following the patient closely with serial MRI or arthroscopic examination as indicated.7 Given the location of the PVNS in this patient and the localized nodular form, surgical excision through open synovectomy was the treatment chosen.
- Pigmented villonodular synovitis (PVNS) is a benign proliferation of synovial cells and mesenchymal supporting tissue that occurs most often in the knees, ankles, and hips; sometimes in the wrists and shoulders; and, rarely, in the elbow. The disorder normally affects synovial joints and synovial sheaths of tendons. However this case indicates that, though extremely rare, PVNS can also affect other areas, such as the distal biceps tendon.
- The diffuse form of PVNS needs to be followed more closely than the localized form and is found in the knee; hip; ankle; shoulder; and, rarely, the elbow.
- Most patients with PVNS will present with a progressively painful arthralgia with progressive loss in range of motion and development of a palpable mass.
- MRI is commonly used to identify PVNS in conjunction with histopathology of tissue specimens.
- In many cases, arthroscopic or open synovectomy provides resolution of the complaint.
Surgery in this case was successful and without complication, although long-term follow-up is needed to watch for recurrence. The arm was put into a posterior splint with lateral strut. The elbow was placed in 90° of flexion and in neutral forearm rotation for 1 week, after which motion was started. The pathology report was reviewed with the patient. At follow-up 2 months later, she reported that the swelling had gone down and the pain was minimal. She had returned to her activities of daily living. There were no signs of recurrence on examination, and she had full ROM of the elbow. Six months later, the patient had no evidence of recurrence and no pain or restricted elbow ROM.
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