PET, CT, and MR Imaging of Extra-articular Pigmented Villonodular Synovitis

A severe headache due to pigmented villonodular synovitis in a rare location: facial nerve on temporomandibular joint. A case report

BACKGROUND

Pigmented villonodular synovitis (PVNS) is an infrequent benign tumor-like proliferative lesion developing from the synovial membranes of the joint, tendon sheath, and bursa.

CLINICAL PRESENTATION

A 44-year-old woman with numbness on the right side of her face, severe headaches, and swelling in temporomandibular region is presented. On head and neck magnetic resonance imaging, an encapsulated mass approximately 2 cm was detected. The fine-needle aspiration biopsy resulted as suspicion of mesenchymal tumor. A complete resection with the capsule was performed over the temporal branch by monitoring of the facial nerve. The final histopathologic examination resulted as a giant cell tendon sheath tumor.

CONCLUSION

Headache is not the main symptom in PVNS, but in severe pain spreading from the temporomandibular region, physical examination should be done carefully for slight swelling, and the possibility of pigmented villonodular synovitis should be considered. Because of the high recurrence rate, en bloc resection is necessary.

Grading System and Surgical Strategy for Temporal Bone Diffuse-Type Tenosynovial Giant Cell Tumor

OBJECTIVES

To develop a novel grading system and appropriate surgical approaches for patients with diffuse type tensosynovial giant cell tumor (D-TGCT) of the temporal bone.

STUDY DESIGN

Retrospective cohort study.

METHODS

We retrospectively reviewed 31 patients with temporal bone D-TGCT between June 2012 and July 2021. All patients underwent comprehensive clinical evaluations, including clinical presentations, hearing threshold, imaging studies, surgical approaches, and prognosis. A grading system was developed based on the tumor location and adjacent neurovascular structures involvement according to imaging and intraoperative findings.

RESULTS

In this study, grade II tumors were the most common (13/31), followed by grades I (7/31), III (7/31), and IV (4/31) tumors. Seven grade I patients received the subtemporal middle cranial fossa approach (SMCF) combined with the canal wall up mastoidectomy and tympanoplasty (CWUT). Nine grade II patients underwent SMCF combined with subtotal petrosectomy (SPTR), and four grade II patients underwent SMCF combined with CWUT. Seven grade III patients received SMCF combined with SPTR and dura mater reconstruction, and four grade IV patients underwent infratemporal fossa approach type B. Gross total resection was achieved in all patients, and the median follow-up time was 30.1 months (range, 4-96 months). Three patients (one grade II, one grade III, and one grade IV) had recurrence during follow-up, and the patient with grade III tumor had two recurrences.

CONCLUSIONS

Gross total resection is the first-line treatment for patients with D-TGCT of the temporal bone. This novel grading system enables surgeons to select optimal surgical strategy. Long-term follow-up is mandatory postoperatively.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Diffuse-type tenosynovial giant cell tumor of the temporomandibular joint with skull base invasion: a report of 22 cases with literature review

OBJECTIVES

The aim of this study was to retrospectively analyze the clinical characteristics, surgical treatment, and prognosis of patients with diffuse-type tenosynovial giant cell tumor (D-TGCT) involving the temporomandibular joint (TMJ) and the skull base.

STUDY DESIGN

A retrospective study was performed in patients with D-TGCT involving the TMJ and the skull base at our institute from April 2009 to August 2018. Data on clinical characteristics, surgical treatment, and prognosis were collected and analyzed. A literature search on D-TGCT involving the TMJ was conducted and the data analyzed.

RESULTS

The study included 22 patients (14 males and 8 females), with an average age of 44 years. The main symptoms were headache and hearing limitation, accompanied by a swelling in the TMJ area. Magnetic resonance imaging (MRI) showed low signals on T1- and T2-weighted images. All lesions were completely removed. Temporal bone flap, titanium mesh, and temporal muscle flap were used for reconstruction. The recurrence rate was 4.5%. In the literature, 115 cases were reported. Surgery alone was performed in 88 cases; postoperative radiotherapy was performed in 19 cases; the tumor recurrence rates were 9.1% and 15.8% for the 2 procedures, respectively. All patients were alive at the end of the follow-up period.

CONCLUSIONS

D-TGCT involving the TMJ and the skull base is a locally aggressive but benign lesion necessitating complete resection and has a good prognosis.

Diffuse-Type Tenosynovial Giant Cell Tumor of the Thoracic Spine: Appearance on FDG PET/CT

D-TGCT (diffuse-type tenosynovial giant cell tumor) is a benign proliferative disorder of the synovial membranes that usually occurs in the appendicular skeleton, especially large joints such as the knee, hip, and elbow. It rarely involves the spine. In this report, we describe a rare case of D-TGCT in the thoracic spine, which showed a lytic lesion with high FDG uptake. It can mimic metastases or neurogenic tumors and should be included in the differential diagnosis of spinal tumors.

Imaging features for diffuse-type tenosynovial giant cell tumor of the temporomandibular joint: A case report

RATIONALE

The tenosynovial giant cell tumor (TGCT) is a benign but locally aggressive tumor that arises from the synovial membrane of joints, tendon sheaths, and bursae. Although any joint can be affected, involvement of the temporomandibular joint (TMJ) was reported very rarely, and there is no relevant report on F-FDG PET/computerized tomography (CT).

PATIENT CONCERNS AND DIAGNOSES

We present here a rare case of diffuse-type of TGCT (D-TGCT) arising from the right TMJ in a 74-year-old woman. The patient was discovered a mass of the right temporal fossa during a head CT scan. However, she did not receive any treatment and was discharged from the hospital. She visited our institution again after 4 years with worsening headache and swelling of the right preauricular area. An enhanced CT demonstrated a 6.0 × 3.4 × 5.0 cm mass of mixed density involving the right TMJ, with evident enhancement and extensive erosion of adjacent bones. Magnetic resonance imaging (MRI) showed hypointensity in the solid part of the mass but high signal intensity in the cystic part or necrosis on T2-weighted images (T2WI). In F-FDG PET/CT images, the solid portion of the mass had increased FDG uptake with a SUVmax of 19.8. It was then diagnosed as D-TGCT by postoperative pathology.

LESSONS

The case report shows the imaging features of the TGCT, including CT, MRI, and F-FDG PET/CT, especially the typical hypointensity on T2WI. Careful preoperative examination and complete resection are the factors that lead to the optimal treatment of the TGCT.

Spectrum of Benign Articular and Periarticular Findings at FDG PET/CT

Whole-body fluorine 18 fluorodeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) is performed primarily for oncologic indications; however, FDG uptake is not specific for malignancy. Herein we focus on causes of increased FDG uptake in and around joints, as lesions in these locations are commonly benign. A combination of primary intra-articular processes and osseous processes that may occur near the joint space will be discussed. Causes of intra-articular and periarticular increased FDG activity can be broadly divided into infectious, inflammatory, degenerative, and benign neoplastic categories. A familiarity with the full range of these processes is important to avoid misinterpretation, in turn decreasing unnecessary follow-up studies, procedures, and treatments. Differentiation from malignancy is often possible on the basis of a different level of FDG activity, divergent response to therapy, or differing changes over time, in comparison with a patient's known primary cancer. Recognizing an intra-articular lesion location can also be critical, as intra-articular metastases are rare. In some cases, benign FDG-avid articular and periarticular entities have a specific appearance at FDG PET/CT and a correct diagnosis may be made without any additional workup. In most other cases, comparison with prior studies and/or additional imaging can afford an accurate diagnosis. This review is meant to introduce the reader to a spectrum of benign FDG-avid articular and periarticular processes that may be encountered at oncologic FDG PET/CT to increase confidence and diagnostic accuracy. (©)RSNA, 2016.

Nonsurgical giant cell tumour of the tendon sheath or of the diffuse type: are MRI or 18F-FDG PET/CT able to provide an accurate prediction of long-term outcome?

PURPOSE

To investigate whether MRI (RECIST 1.1, WHO criteria and the volumetric approach) or (18)F-FDG PET/CT (PERCIST 1.0) are able to predict long-term outcome in nonsurgical patients with giant cell tumour of the tendon sheath or of the diffuse type (GCT-TS/DT).

METHODS

Fifteen "nonsurgical" patients with a histological diagnosis of GCT-TS/DT were divided into two groups: symptomatic patients receiving targeted therapy and asymptomatic untreated patients. All 15 patients were evaluated by MRI of whom 10 were treated, and a subgroup of 7 patients were evaluated by PET/CT of whom 4 were treated. Early evolution was assessed according to MRI and PET/CT scans at baseline and during follow-up. Cohen's kappa coefficient was used to evaluate the degree of agreement between PERCIST 1.0, RECIST 1.1, WHO criteria, volumetric approaches and the reference standard (long-term outcome, delay 505 ± 457 days). The response rate in symptomatic patients with GCT-TS/DT receiving targeted therapy was also assessed in a larger population that included additional patients obtained from a review of the literature.

RESULTS

The kappa coefficients for agreement between RECIST/WHO/volumetric criteria and outcome (15 patients) were respectively: 0.35 (p = 0.06), 0.26 (p = 0.17) and 0.26 (p = 0.17). In the PET/CT subgroup (7 patients), PERCIST was in perfect agreement with the late symptomatic evolution (kappa = 1, p < 0.05). In the treated symptomatic group including the additional patients from the literature the response rates to targeted therapies according to late symptomatic assessment, and PERCIST and RECIST criteria were: 65 % (22/34), 77 % (10/13) and 26 % (10/39).

CONCLUSION

(18)F-FDG PET/CT with PERCIST is a promising approach to the prediction of the long-term outcome in GCT-TS/DT and may avoid unnecessary treatments, toxicity and costs. On MRI, WHO and volumetric approaches are not more effective than RECIST using the current thresholds.

Localized tenosynovial giant cell tumor in both knee joints

Tenosynovial giant cell tumor, previously called pigmented villonodular synovitis (PVNS), is a rare benign neoplastic process that may involve the synovium of the joint. The disorder is usually monoarticular and only a few cases have been reported on polyarticular involvement. Herein, we present a case of localized intra-articular tenosynovial giant cell tumor in a 29-year-old man involving both knee joints with a description of the MR imaging and histological findings.