Multifocal Desmoid-Type Fibromatosis: Case Series and Potential Relationship to Neuronal Spread.

Multifocal desmoid-type fibromatosis (DTF) is very rare and usually regional. We report three cases that initially appeared to be multifocal, but subsequent detailed imaging revealed unsuspected tracking along nerves in two cases. This neural spread is reminiscent of neuromuscular choristoma (NMC), a rare developmental lesion in which mature skeletal muscle cells, or rarely smooth muscle cells, infiltrate and enlarge peripheral nerves. NMC is frequently associated with DTF. These two cases suggest that DTF spread along nerves and appeared as distinct multifocal lesions while actually being contiguous. The third case was felt to represent true multifocal tumor development, possibly due to tumor seeding at the time of chest surgery. The relationship of DTF to NMC is discussed.

Evaluation of lesion and overlying articular cartilage in patients with juvenile osteochondritis dissecans of the knee using quantitative diffusion MRI.

Current clinical MRI of patients with juvenile osteochondritis dissecans (JOCD) is limited by the low reproducibility of lesion instability evaluation and inability to predict which lesions will heal after nonoperative treatment and which will later require surgery. The aim of this study is to verify the ability of apparent diffusion coefficient (ADC) to detect differences in lesion microstructure between different JOCD stages, treatment groups, and healthy, unaffected contralateral knees. Pediatric patients with JOCD received quantitative diffusion MRI between January 2016 and September 2020 in this prospective research study. A disease stage (I-IV) and stability of each JOCD lesion was evaluated. ADCs were calculated in progeny lesion, interface, parent bone, cartilage overlying lesion, control bone, and control cartilage regions. ADC differences were evaluated using linear mixed models with Bonferroni correction. Evaluated were 30 patients (mean age, 13 years; 21 males), with 40 JOCD-affected and 12 healthy knees. Nine patients received surgical treatment after MRI. Negative Spearman rank correlations were found between ADCs and JOCD stage in the progeny lesion (ρ = -0.572; p < 0.001), interface (ρ = -0.324; p = 0.041), and parent bone (ρ = -0.610; p < 0.001), demonstrating the sensitivity of ADC to microstructural differences in lesions at different JOCD stages. We observed a significant increase in the interface ADCs (p = 0.007) between operative (mean [95% CI] = 1.79 [1.56-2.01] × 10-3 mm2 /s) and nonoperative group (1.27 [0.98-1.57] × 10-3 mm2 /s). Quantitative diffusion MRI detects microstructural differences in lesions at different stages of JOCD progression towards healing and reveals differences between patients assigned for operative versus nonoperative treatment.

Longitudinal 3T MRI T2 * mapping of Juvenile osteochondritis dissecans (JOCD) lesions differentiates operative from non-operative patients-Pilot study.

Juvenile osteochondritis dissecans (JOCD) is an orthopedic joint disorder of children and adolescents that can lead to premature osteoarthritis. Thirteen patients (mean age: 12.3 years, 4 females), 15 JOCD-affected and five contralateral healthy knees, that had a baseline and a follow-up magnetic resonance imaging (MRI) (mean interval of 8.9 months) and were treated nonoperatively during this interval were included. Retrospectively, patients were assigned to operative or nonoperative groups based on their electronic medical records. Volumetric mean T2 * values were calculated within regions of interest (progeny lesion, interface, parent bone) and region matched control bone in healthy contralateral knees and condyles. The normalized percentage difference of T2 * between baseline and follow up MRI in nonoperative patients significantly increased in progeny lesion (-47.8%, p < 0.001), parent bone (-13.9%, p < 0.001), and interface (-32.3%, p = 0.011), whereas the differences in operative patients were nonsignificant and below 11%. In nonoperative patients, the progeny lesion (p < 0.001) and interface T2 * values (p = 0.012) were significantly higher than control bone T2 * at baseline, but not at follow-up (p = 0.219, p = 1.000, respectively). In operative patients, the progeny lesion and interface T2 * values remained significantly elevated compared to the control bone both at baseline (p < 0.001, p < 0.001) and follow-up (p < 0.001, p < 0.001), respectively. Clinical Significance: Longitudinal T2 * mapping differentiated nonhealing from healing JOCD lesions following initial nonoperative treatment, which may assist in prognosis and improve the ability of surgeons to make recommendations regarding operative versus nonoperative treatment.

Compositional evaluation of lesion and parent bone in patients with juvenile osteochondritis dissecans of the knee using T2 * mapping.

Juvenile osteochondritis dissecans (JOCD) lesions contain cartilaginous, fibrous and osseous tissues which are difficult to distinguish with clinical, morphological magnetic resonance imaging (MRI). Quantitative T2 * mapping has earlier been used to evaluate microstructure and composition of all aforementioned tissues as well as bone mineral density. However, the ability of T2 * mapping to detect changes in tissue composition between different JOCD lesion regions, different disease stages, and between stable and unstable lesions has not been demonstrated. This study analyzed morphological and T2 * MRI data from 25 patients (median age, 12.1 years) with 34 JOCD-affected and 13 healthy knees. Each lesion was assigned a stage reflecting the natural history of JOCD, with stages I and IV representing early and healed lesion, respectively. T2 * values were evaluated within the progeny lesion, interface and parent bone of each lesion and in the control bone region. T2 * was negatively correlated with JOCD stage in progeny lesion (ρ = -0.871; p < 0.001) and interface regions (ρ = -0.649; p < 0.001). Stage IV progeny showed significantly lower T2 * than control bone (p = 0.028). T2 * was significantly lower in parent bone than in control bone of patients with stable lesions (p = 0.009), but not in patients with unstable lesions (p = 0.14). Clinical significance: T2 * mapping enables differentiation between different stages of JOCD and quantitative measurement of the ossification degree in progeny lesion and interface. The observed T2 * decrease in healed and stable lesions may indicate increased bone density as a result of the active repair process. T2 * mapping provides quantitative information about JOCD lesion composition.

A Novel Tongue-Based Tumor With an RREB1-MRTFB Fusion: Variant Rhabdomyosarcoma or Aggressive Variant of Ectomesenchymal Chondromyxoid Tumor.

The presence of a FOXO1 fusion in a tumor is one of the most important prognostic factors in rhabdomyosarcoma. Most histologically defined alveolar rhabdomyosarcomas bear a FOXO1 fusion. We discuss a case that was initially thought to be a rhabdomyosarcoma but was later discovered to have an RREB1-MRTFB fusion. This fusion has never been reported in rhabdomyosarcoma but typically characterizes ectomesenchymal chondromyxoid tumor (ECT), a neoplasm with typically rather benign behavior. In this article, the authors discussed whether this patient's aggressive presentation represents a variation of ECT or an unusual case of rhabdomyosarcoma.

Multiple malignant tumors in a patient with familial chordoma, a case report.

BACKGROUND: Chordoma is a rare bone tumor that is typically resistant to chemotherapy and is associated with genetic abnormalities of the T-box transcription factor T (TBXT) gene, which encodes the transcription factor brachyury. Brachyury is felt to be a major contributor to the development of chordomas. CASE PRESENTATION: We describe a 67-year-old woman who developed an undifferentiated pleomorphic sarcoma in her thigh. Despite treatment with standard chemotherapy regimens, she had a rapidly progressive course of disease with pulmonary metastases and passed away 8 months from diagnosis with pulmonary complications. Her medical history was remarkable in that she had a spheno-occipital chordoma at age 39 and later developed multiple other tumors throughout her life including Hodgkin lymphoma and squamous cell carcinoma and basal cell carcinoma of the skin. She had a family history of chordoma and her family underwent extensive genetic study in the past and were found to have a duplication of the TBXT gene. CONCLUSIONS: Brachyury has been found to associate with tumor progression, treatment resistance, and metastasis in various epithelial cancers, and it might play roles in tumorigenesis and aggressiveness in this patient with multiple rare tumors and germ line duplication of the TBXT gene. Targeting this molecule may be useful for some malignancies.

Using a simplified version of a common surgical grading scale for acetabular labral tears improves the utility of preoperative hip MRI for femoroacetabular impingement.

OBJECTIVE: To evaluate whether a commonly used surgical grading scale, when applied to acetabular labral findings on MRI, could improve preoperative planning and counseling for patients undergoing hip arthroscopy. MATERIALS AND METHODS: We evaluated 76 clinical MRIs performed on patients with femoroacetabular impingement. Three musculoskeletal radiologists and one musculoskeletal fellow reviewed each scan in a blinded fashion, classifying the acetabular labrum from 12:00 to 4:00 using the Beck scale, a common surgical grading scale. Clinical correlation was provided via surgical examination and classification. Reliability was determined between readers and between reader and surgical data using Cohen's kappa and Krippendorff's alpha at each clock position and for the worst grading for each scan. In addition, a simplified version of the scale comprised of only two grades, potentially reparable and not potentially reparable, was evaluated. RESULTS: When the scale was simplified into categories of potentially reparable and not potentially reparable, the sensitivity was excellent, ranging from 85.5 to 96%. Observer agreement when using individual Beck grades was found to range from poor to fair; Kappa ranged from 0.03 to 0.19, and Alpha ranged from - 0.27 to 0.22. CONCLUSION: The simplified version of the Beck labral scale when applied to MRI is a highly sensitive predictor of potentially reparable labral pathology while excluding normal and grossly degenerative tissue. Use of this scale provides clinically relevant information that can drive preoperative planning and improve patient counseling. It does so in a standardized fashion that can be applied across practice sites and without additional cost.

Reliability of EOS compared to conventional radiographs for evaluation of lower extremity deformity in adult patients.

OBJECTIVE: The purpose of this study was to compare reliability of lower extremity imaging measurements using EOS and conventional X-ray (CR) of adult patients with mechanical axis malalignment. MATERIALS AND METHODS: Ten patients (20 lower limbs) of mean age of 31.6 years (range 21-39) with post-traumatic deformities who presented for evaluation of osteotomies and/or ligament and cartilage reconstructions were prospectively enrolled. Two independent observers performed full-length anterior-posterior (AP) measurements 2 weeks apart on both CXR and two-dimensional (2D) EOS images. Measurements included weight-bearing axis (WBA), varus/valgus angle (V/V), femoral length (FL), tibial length (TL), femoral mechanical axis (FMA), tibial mechanical axis (TMA), and total limb length (TLL). Reliability was determined with random effects modeling of intraclass correlation coefficients (ICC) set to consistency. Three statistical operations were performed to compare interrater validity in CXR and EOS: students' two-sample t test, paired two-sample t test, and Pearson's correlative r-statistical agreement. RESULTS: There was a statistically significant difference for V/V, FL, and TLL (all p < 0.01) between CXR and EOS. A relatively large proportion of the population consistently had larger V/V measures for EOS compared to CXR. In contrast, the FL and TLL measures were consistently larger for CXR compared to EOS. The differences between CXR and EOS measurements were statistically significant, though the small differences in values were not clinically meaningful. Agreement of all measures remained high (r = 0.84-0.99). CONCLUSION: Using 2D EOS for lower extremity measurements is reproducible, reliable, and comparable to the gold standard, standing long leg radiographs.

Pseudomyogenic hemangioendothelioma-A case report and review of the literature.

Pseudomyogenic hemangioendothelioma (PMH) of bone is a very rare tumor and frequently presents at multiple locations. PMH is difficult to diagnose by imaging and histopathologic features. Various and partially discordant imaging findings have been reported in case reports and small case series. We report a case of a 63-year-old man with PMH isolated to the sacrum, presenting with chronic intermittent buttock pain that was incidentally identified on imaging for acute pancreatitis. We believe that learning about PMH of bone will help to include this disease in the differential diagnosis of lytic lesions of the sacrum. Becoming aware of the various and sometimes discordant imaging findings of this rare entity is important and helpful for radiologists, pathologists, and orthopedic surgeons.

Giant Cell Tumor within the Proximal Tibia after ACL Reconstruction.

26-year-old female with prior anterior cruciate ligament reconstruction developed an enlarging lytic bone lesion around the tibial screw with sequential imaging over the course of one year demonstrating progression of this finding, which was confirmed histologically to be a giant cell tumor of bone. The lesion originated around the postoperative bed, making the diagnosis challenging during the early course of the presentation. The case demonstrates giant cell tumor which originated in the metaphysis and subsequently grew to involve the epiphysis; therefore, early course of the disease not involving the epiphysis should not exclude this diagnosis.