Desmoplastic fibroma with perineural spread: conventional and diffusion-weighted magnetic resonance imaging findings

Neuromuscular choristoma-associated desmoid-type fibromatosis: Establishing a nerve territory concept

INTRODUCTION

Desmoid-type fibromatosis (DTF) frequently arises in patients with neuromuscular choristoma (NMC). We hypothesize that NMC-associated DTF occurs in soft tissues innervated by the NMC-affected nerve, and arises from CTNNB1-mutated (myo) fibroblasts within or directly adjacent to the NMC.

MATERIALS AND METHODS

A retrospective review of patients treated at our institution was performed for patients with biopsy-confirmed diagnosis of NMC-DTF. Clinical presentation, physical examination, electrodiagnostic findings and radiological features (MR and FDG PET/CT images for each NMC-DTF) and pathologic re-review of available materials were analyzed. A literature review was also performed.

RESULTS

Eight patients from our institution met the inclusion criteria. All patients presented with neuropathic symptoms and soft tissue or bone changes in the nerve territory innervated by the NMC. All MR images (N=8 cases) showed the characteristic features of NMC, and also showed direct contact between unifocal (N=5) or multifocal (N=3) DTF(s) and the NMC-affected nerve NMC. FDG PET/CT (N=2 cases) showed diffuse, increased FDG uptake along the entire affected nerve segment, contiguous with the FDG-avid DTF. In all cases, the DTFs arose in the soft tissues of the NMC-affected nerve's territory. No patient developed DTF at any other anatomic site.

CONCLUSIONS

These data demonstrate that NMC-DTF arises solely within the NMC-affected nerve territory, and has direct contact with the NMC itself. Based on all these findings and the multifocality of NMC in several cases, we recommend imaging and surveillance of the entire NMC-affected nerve (from spine to distal extremity) to identify clinically-occult DTF in patients with NMC.

Recurrent desmoid-type fibromatosis associated with underlying neuromuscular choristoma

OBJECTIVE

Desmoid-type fibromatosis (DTF) presents a therapeutic dilemma. While lacking metastatic potential, it is a locally aggressive tumor with a strong propensity for occurrence near nerve(s) and recurrence following resection. In this study, the authors introduce the association of an occult neuromuscular choristoma (NMC) identified in patients with DTF.

METHODS

After experiencing a case of DTF found to have an occult NMC, the authors performed a retrospective database review of all other cases of biopsy-proven DTF involving the extremities or limb girdles in patients with available MRI data. Two musculoskeletal radiologists with expertise in peripheral nerve imaging reviewed the MRI studies of the eligible cases for evidence of previously unrecognized NMC.

RESULTS

The initial case of a patient with an occult sciatic NMC is described. The database review yielded 40 patients with DTF-18 (45%) in the upper limb and 22 (55%) in the lower limb. Two cases (5%) had MRI findings of NMC associated with the DTF, one in the proximal sciatic nerve and the other in the proximal tibial and sural nerves.

CONCLUSIONS

The coexistence of NMC may be under-recognized in a subset of patients with extremity DTF. This finding poses implications for DTF treatment and the likelihood of recurrence after resection or biopsy. Further study may reveal crucial links between the pathogenesis of NMC and DTF and offer novel therapeutic strategies.

Ischiofemoral impingement secondary to valgus intertrochanteric osteotomy: a case report

We report an unusual case of ischiofemoral impingement secondary to valgus intertrochanteric osteotomy. The osteotomy was performed for treatment of epiphysiolysis of the left femoral head.

Diagnostic performance of magnetic resonance imaging in the assessment of periosteal reactions in bone sarcomas using conventional radiography as the reference

Objective:

To evaluate the performance of magnetic resonance imaging (MRI) in detecting periosteal reactions and to compare MRI and conventional radiography (CR) in terms of the classification of periosteal reactions.

Materials and Methods:

Retrospective study of 42 consecutive patients (mean age, 22 years; 20 men) with a confirmed diagnosis of osteosarcoma or Ewing's sarcoma, MRI and CR images having been acquired pretreatment. Three blinded radiologists detected periosteal reactions and evaluated each periosteal reaction subtype in CR and MRI images: Codman's triangle; laminated; and spiculated. The CR was used as a benchmark to calculate the diagnostic performance. We used the kappa coefficient to assess interobserver reproducibility. A two-tailed Fisher's exact test was used in order to assess contingency between CR and MRI classifications.

Results:

In the detection of periosteal reactions, MRI showed high specificity, a high negative predictive value, and low-to-moderate sensitivity. For CR and for MRI, the interobserver agreement for periosteal reaction was almost perfect, whereas, for the classification of different subtypes of periosteal reaction, it was higher for the Codman's triangle subtype and lower for the spiculated subtype. There was no significant difference between MRI and CR in terms of the classifications (p < 0.05).

Conclusion:

We found no difference between MRI and CR in terms of their ability to classify periosteal reactions. MRI showed high specificity and almost perfect interobserver agreement for the detection of periosteal reactions. The interobserver agreement was variable for the different subtypes of periosteal reaction.

Evaluation of the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer, according to the American College of Radiology criteria

Objective

To evaluate the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer.

Materials and Methods

This was a retrospective, single-center study, conducted by reviewing medical records and imaging reports. We included 1060 female patients who underwent magnetic resonance imaging of the pelvis at a cancer center between January 2013 and June 2014. The indications for performing the examination were classified according to the American College of Radiology (ACR) criteria.

Results

The mean age of the patients was 52.6 ± 14.8 years, and 49.8% were perimenopausal or postmenopausal. The majority (63.9%) had a history of cancer, which was gynecologic in 29.5% and nongynecologic in 34.4%. Of the patients evaluated, 44.0% had clinical complaints, the most common being pelvic pain (in 11.5%) and bleeding (in 9.8%), and 34.7% of patients had previously had abnormal findings on ultrasound. Most (76.7%) of the patients met the criteria for undergoing magnetic resonance imaging, according to the ACR guidelines. The main indications were evaluation of tumor recurrence after surgical resection (in 25.9%); detection and staging of gynecologic neoplasms (in 23.3%); and evaluation of pelvic pain or of a mass (in 17.1%).

Conclusion

In the majority of the cases evaluated, magnetic resonance imaging was clearly indicated according to the ACR criteria. The main indication was local recurrence after surgical treatment of pelvic malignancies, which is consistent with the routine protocols at cancer centers.

Unusual lesions that distend the knee joint: pictorial essay

The high number of knee imaging exams at radiology clinics, together with the wide variety of knee disorders, calls for expanding the knowledge about the less common lesions seen in routine diagnostic practice. The purpose of this pictorial essay was to illustrate unusual lesions that distend the knee joint, selected by relevance and evaluated with multiple imaging modalities, including X-ray, computed tomography, and magnetic resonance imaging, as well as to perform a brief review of the literature.