Tumores articulares y periarticulares: diagnóstico diferencial con resonancia magnética

Imaging of Adult Malignant Soft Tissue Tumors of the Spinal Canal: A Guide for Spine Surgeons

BACKGROUND

Malignant soft tissue spinal canal tumors compromise 20% of all spinal neoplasms. They may be primary or metastatic lesions, originating from a diverse range of tissues within and surrounding the spinal canal. These masses can present as diverse emergencies such as secondary cauda equina syndrome, vascular compromise, or syringomyelia. Interpretation of malignant soft tissue spinal canal tumors imaging is an essential for non-radiologists in the setting of emergencies. This task is intricate due to a great radiologic pattern overlap among entities.

METHODS

We present a step-by-step strategy that can guide nonradiologists identify a likely malignant soft tissue lesion in the spinal canal based on imaging features, as well as a review of the radiologic features of malignant soft tissue spinal canal tumors.

RESULTS

Diagnosis of soft tissue spinal canal malignancies starts with the identification of the lesion's spinal level and its relationship to the dura and medulla. The second step consists of characterizing it as likely-malignant based on radiological signs like a larger size, ill-defined margins, central necrosis, and/or increased vascularity. The third step is to identify additional imaging features such as intratumoral hemorrhage or cyst formation that can suggest specific malignancies. The physician can then formulate a differential diagnosis. The most encountered malignant soft tissue tumors of the spinal canal are anaplastic ependymomas, anaplastic astrocytomas, metastatic tumors, lymphoma, peripheral nerve sheath tumors, and central nervous system melanomas. A review of the imaging features of every type/subtype of lesion is presented in this work. Although magnetic resonance imaging remains the modality of choice for spinal tumor assessment, other techniques such as dynamic contrast agent-enhanced perfusion magnetic resonance imaging or diffusion-weighted imaging could guide diagnosis in specific situations.

CONCLUSIONS

In this review, diagnostic strategies for several spinal cord tumors were presented, including anaplastic ependymoma, metastatic spinal cord tumors, anaplastic and malignant astrocytoma, lymphoma, malignant peripheral nerve sheath tumors , and primary central nervous system melanoma. Although the characterization of spinal cord tumors can be challenging, comprehensive knowledge of imaging features can help overcome these challenges and ensure optimal management of spinal canal lesions.

Proximal Tibiofibular Joint Arthrodesis Due to Recurrent Giant Ganglion Cyst Causing Peroneal Nerve Palsy

Ganglion cysts are masses that we encounter frequently in our daily practice, usually in the upper extremity, less frequently in the lower extremities, and rarely cause compression symptoms. We present a case of a massive ganglion cyst of the lower limb causing peroneal nerve compression, managed with excision and proximal tibiofibular joint arthrodesis to prevent recurrence. Examination and radiological imaging of a 45-year-old female patient who was admitted to our clinic showed new-onset weakness in right foot movements and numbness on the dorsum of the foot and lateral cruris, a mass consistent with a ganglion cyst expanding the muscle was detected in the peroneus longus muscle. In the first surgery, the cyst was carefully resected. After three months, the patient came with a repeated mass on the lateral side of the knee. After confirmation of the ganglion cyst with clinical examination and MRI, a second surgery was planned for the patient. In this stage, we performed a proximal tibiofibular arthrodesis for the patient. Her symptoms recovered during the early follow-up period and no recurrence occurred during the two years of the follow-up period. Although the treatment of ganglion cysts seems easy, it can sometimes be challenging. We think that arthrodesis may be a good treatment option in recurrent cases.

Pediatric solid intra-articular masses of the knee: prevalence, imaging features and etiologies

BACKGROUND

The etiologies of pediatric solid intra-articular soft-tissue masses are not well described and can present diagnostic dilemmas.

OBJECTIVE

Our hypothesis was that these entities have a limited differential diagnosis and are mostly benign.

MATERIALS AND METHODS

We reviewed knee magnetic resonance imaging (MRI) scans performed at our tertiary care institution between 2001 and 2019 (n=3,915). Our inclusion criterion was knee MRI with a solid intra-articular soft-tissue mass. Our exclusion criteria were cases with no masses or non-solid intra-articular lesions with clear radiologic diagnoses. Multiple radiologic characteristics were evaluated. Radiologic and histological diagnoses were collected when available. Cases without histology were assigned a suspected diagnosis.

RESULTS

Twenty-five out of 3,915 (<1%) cases met the inclusion/exclusion criteria. Twenty patients underwent biopsy. Patient age ranged from 1 to 19 years with a mean age of 12 years. Lesion size ranged from 1 to 7 cm with a mean of 3.3 cm. The top three histological diagnoses were pigmented villonodular synovitis (PVNS) (7/20, 35%), vascular malformations (2/20, 10%) and inflammatory arthritis (2/20, 10%). There was one malignant case of synovial sarcoma (1/20, 5%). Of the five cases without biopsies, PVNS was the most common diagnosis (3/5, 60%). Five out of 10 (50%) PVNS cases were focal and 5/10 (50%) were multifocal. All PVNS cases (10/10, 100%) had hypointense signal on T2.

CONCLUSION

Solid intra-articular soft-tissue masses of the knee in children are rare, with a prevalence of <1% in our study. The vast majority are benign with PVNS being the most common diagnosis.

Feasibility of MRI in diagnosis and characterization of intra-articular synovial masses and mass-like lesions

Background

Classifications of intra-articular masses are infectious granulomatous diseases, non-infectious synovial proliferative processes (synovial chondromatosis, lipoma arborescens, rheumatoid arthritis, pigmented villonodular synovitis [PVNS]), vascular malformations, deposition disorders, neoplastic, and miscellaneous conditions. The aim of this study is to correlate the results of MRI with arthroscopy in characterization of different varieties of intra-articular synovial masses and mass-like lesions. This observational prospective study was conducted between February 2018 and August 2019. We screened 1000 routine musculoskeletal MRI examination during this period, 32 of which showed intra-articular synovial masses/mass-like lesions. The selected 32 patients (20 males and 12 females) have a mean age of 49.20 ± 2.0 years; all presented with joint swelling, pain, or difficulty of movement according to the joint affected. All patients underwent arthroscopy for histopathological correlation.

Results

The final diagnosis was synovial chondromatosis in 14 patients (43.8%), PVNS in ten patients (31.3%), and lipoma arborescens in five patients (15.6%). Synovial chondrosarcoma, synovial hematoma, and synovial ganglion cyst each in one patient (3.1%). The concordance of MRI to arthroscopy was 96.6% accuracy, 91.7% sensitivity, 99% specificity, 52.3% PPV, and 99.9% NPV.

Conclusion

Good correlation was observed between MRI and arthroscopy in diagnosis of intra-articular synovial masses/mass-like lesions.