Imaging of Soft Tissue Neoplasms in the Adult: Malignant Tumors

Does the apparent diffusion coefficient from diffusion-weighted MRI imaging aid in the characterization of malignant soft tissue tumors and sarcomas

OBJECTIVE

To identify trends in apparent diffusion coefficient (ADC) measurements from diffusion-weighted imaging (DWI) with respect to tumor type classification and other tumor characteristics whether common malignant soft tissue tumors can be distinguished.

MATERIALS AND METHODS

A consecutive series of extremity malignant soft tissue tumors and soft tissue sarcomas (STS) among 78 adult patients with conventional MRI and DWI were included. Each case was evaluated with respect to T1/T2 signal alterations and heterogeneity, presence of peritumoral edema, necrosis, cystic changes, internal hemorrhage, and maximum longitudinal dimension blinded to the histology. The ADC mean and minimum were obtained using a free-hand region of interest of the whole tumor and the darkest (lowest signal area) ADC area of the tumor. Kruskal-Wallis and Wilcoxon Rank-Sum Tests were used to determine associations and significance between tumor subtypes. Intraclass correlation (ICC) and kappa calculations were utilized to assess inter-reader agreements for ADC values and reader diagnosis.

RESULTS

Liposarcomas showed more heterogenous T1W images with hyperintense T1W signal when compared to tumors not classified as liposarcoma (P = 0.046 and P = 0.010, respectively). Liposarcomas were relatively consistent in demonstrating an absence of hemorrhage (81.8%) while undifferentiated pleomorphic sarcomas consistently showed intralesional hemorrhage (90%). When comparing individual tumor classifications against the rest of the samples, lymphomas registered lower mean and minimum ADC values in the whole tumor and in the most hypointense area of the tumor for both readers (P < 0.05). The interobserver agreement between the two readers was good to excellent for all four ADC measurements (ICC = 0.65-0.98).

CONCLUSION

Diffusion-weighted imaging generated ADC measurements are reproducible but currently offer limited insight in being able to differentiate among different malignant soft tissue tumor and sarcoma histologies. T1W and T2W signal characteristics also offer limited insight in differentiating between soft tissue malignancies.

Giant hemorrhagic trochanteric bursitis mimicking a high-grade soft tissue sarcoma: report of two cases

BACKGROUND

The giant haemorrhagic bursitis of the hip joint is a rare clinical condition that requires evidence-based guidelines for adequate diagnosis and management. Usually, this pathology requires conservative treatment; however, when abnormal size or clinical symptoms of compression of the surrounding noble structures are reported, an accurate differential diagnosis is required, in order to exclude other malignant conditions that can be included into differential diagnosis, and a surgical approach should be considered. The purpose of this work is to provide an appropriate description of the diagnostic and therapeutic path, providing an accurate analysis of the possible differential diagnoses.

METHODS

We report 2 cases of symptomatic haemorrhagic bursitis of the hip joint, confirmed by histological investigation. In both cases, the patients complained a peripheral nerve deficit of a single limb: one patient presented paresthesia of lateral femoral cutaneous nerve while the second peripheral edema due to compression of the proximal venous and lymphatic circulation.

RESULTS

Both cases were successfully managed by complete surgical excision of the mass, with no  recurrence. There were no major complications, but in first case the nerve deficit was permanent.

CONCLUSIONS

Giant hemorrhagic trochanteric bursitis is a rare condition, but it should be included in the differential diagnosis of soft tissue masses arising from the hip joint. Due to the rarity of this entity, a cautious exclusion process of all plausible differential diagnosis must be undertaken, in order to not miss the possibility of soft-tissue tumors, primarily malignant high-grade sarcomas.

Diagnosis and management of primary malignant tumors in the upper extremity

Bone and soft tissue sarcomas of the upper extremity are relatively uncommon. In many cases, they are discovered incidentally during evaluation of traumatic injuries or common ailments such as rotator cuff tendonitis or tennis elbow. Thus, it is important for all orthopedic surgeons to understand the differential diagnosis, workup, and treatment for upper extremity lesions. An appreciation of the clinical and radiographic features of primary malignant lesions aids in identifying patients that need referral to an orthopedic oncologist and a multidisciplinary team.

Conventional MR and diffusion-weighted imaging of musculoskeletal soft tissue malignancy: correlation with histologic grading

AIM

To evaluate proven soft tissue musculoskeletal malignancies blinded to their Fédération Nationale des Centres de Lutte Contre le Cancer histologic grades to identify the predictive values of conventional MR findings and best fit region of interest (ROI) apparent diffusion coefficient (ADC) measurements.

MATERIALS AND METHODS

Fifty-one consecutive patients with different histologic grades were evaluated by four readers (R1-4) of different experience levels. Quantitatively, the maximum longitudinal size, tumor to muscle signal intensity ratios, and ADC measurements and, qualitatively, the spatial location of the tumor, its signal alterations, heterogeneity, intralesional hemorrhage or fat, and types of enhancement were assessed. Intraclass correlation, weighted kappa, ANOVA, and Fisher exact tests were used.

RESULTS

There were 22/51 (43%) men (mean age ± SD = 52 ± 16 years) and 29/51 (57%) women (mean age ± SD = 54± 17 years), with the majority of tumors 38/51 (75%) in the lower extremities. Histologic grades were I in 8/51 (16%), II in 17/51 (33%), and III in 26/51 (51%), respectively. The longitudinal dimensions were different among three grades (p = 0.0015), largest with grade I. More central enhancements and deep locations were seen in grade III tumors (p = 0.0191, 0.0246). The ADC mean was significantly lower in grade III than in grade I or II (p < 0.0001 and p = 0.04). The ADC min was significantly lower in grade III than in grade I (p = 0.02). Good to excellent agreements were seen for T1/T2 tumor/muscle ratios, longitudinal dimension, and ADC (ICC = 0.60-0.98).

CONCLUSION

Longitudinal tumor dimension, central enhancement, and ADC values differentiate histology grades in musculoskeletal soft tissue malignancy with good to excellent inter-reader reliability.

KEY POINTS

• The longitudinal tumor dimension of grade III malignancy is smaller than that of grade I (p < 0.0001), and higher-grade tumors are located deeper (p = 0.0246). • The ADC mean is significantly lower in grade III than in grade I or grade II (p < 0.0001 and p = 0.04). • The ADC minimum is significantly lower in grade III than in grade I (p = 0.02).

A rare case of localised pigmented villonodular synovitis in the knee of a 24-year-old female soccer player: diagnosis, management and summary of tenosynovial giant cell tumours

Localised pigmented villonodular synovitis (PVNS) of the knee is a rare diagnosis, with clinical signs and symptoms mimicking meniscal damage or other common knee injuries.We report the case of a 24-year-old female soccer player, seeking treatment after 7 months of persisting knee pain. Additionally, we present an overview of tenosynovial giant cell tumours.On examination, the patient was found to have tenderness in the medial joint space of the knee. MRI revealed a heterogeneous formation in the central part of the knee. The formation was completely enucleated arthroscopically, histological analyses confirmed the diagnosis of localised PVNS. The patient was subsequently free of symptoms with no signs of recurrence on MRI and had resumed soccer practice at the 1-year follow-up appointment.

Malignant nerve sheath tumor involving glossopharyngeal, vagus and spinal nerve with intracranial-extracranial extension and systemic metastases in a patient with type 1 neurofibromatosis: A case report

INTRODUCTION

Intracranial malignant peripheral nerve sheath tumors are an extremely rare pathology with a high morbidity and mortality. Epidemiological, clinical and prognostic data are scarce and with little certainty in the literature. The aim of this paper is to report for first time in English literature, the case of a patient with type 1 neurofibromatosis, who presented a malignant peripheral nerve sheath tumor that involved the left glossopharyngeal, vagus and spinal nerves with intracranial and extracranial extension through jugular foramen and systemic metastases.

PRESENTATION OF CASE

A 37 years-old female patient with malnutrition and Villaret́s syndrome. It was confirmed by brain magnetic resonance imaging and PET-CT the presence of a neoplasic lesion which was radiologically compatible with malignant peripheral nerve sheath tumor with systemic metastases. Partial surgical resection was performed; the patient postoperative course was without significant clinical improvement but with added peripheral facial palsy. The patient did not accept adjuvant management because of personal reasons.

DISCUSSION AND CONCLUSION

Behavior therapy is unclear due to the low frequency of the disease and the lack of case series, representing a challenge for the physician in its approach and a poor prognosis for the patient.

A rare case study of a retropharyngeal neurofibroma and a brief literature review

INTRODUCTION

Space occupying lesions in the retropharyngeal space are rare.

CASE REPORT

Here, we present a rare case of a retropharyngeal neurofibroma treated surgically through an open cervical approach without any complication.

DISCUSSION

Neurofibromas are benign, slowly growing neoplasms that could be associated or not with neurofibromatosis. They are derived from peripheral nerves. Diagnostic work-up should include CT-scan and MRI as well as a biopsy to confirm the diagnosis. Treatment of localized and diffuse neurofibromas is often surgical resection, which may require sacrifice of the nerve. Malignant transformation of these lesions, without association to NF-1, is rare and exceptionally documented in the literature.

CONCLUSION

We presented a rare case of solitary neurofibroma of the retropharyngeal space. Complete resection of the lesion was performed without any complication. We also presented a brief review of the literature about neurofibromas.

Unplanned excision of soft-tissue sarcomas: current concepts for management and prognosis

➤ Biopsy, staging, preoperative imaging and planning, as well as surgical treatment of soft-tissue sarcomas, are best carried out in specialized sarcoma centers, with the support of a multidisciplinary tumor board.➤ Tumor bed excision is recommended after most unplanned excisions, with a goal of obtaining complete tumor removal with an appropriately wide margin of resection.➤ The surgical resection area tends to be more extensive during tumor bed excision than during primary resection because of the need to resect potential areas of contamination, resulting in the need for more reconstructive procedures (flaps and skin grafts) and wider radiation fields.➤ Unplanned excisions are associated with an increased rate of local recurrence related to residual disease and positive margins after tumor bed excision, a deep location, and certain histologic subtypes, such as malignant peripheral nerve sheath tumor, myxofibrosarcoma, and dermatofibrosarcoma protuberans.➤ While adjuvant radiation therapy has not been found to mitigate the risk of local recurrence in unplanned excisions, it is generally utilized in the treatment of unplanned excisions as it is in the treatment of primary soft-tissue sarcomas.➤ Given the surgical and oncologic sequelae of unplanned excisions, prevention through the diffusion of concepts by means of provider education on how to approach soft-tissue masses, which can be potential soft-tissue sarcomas, is the best strategy.

Characterization of peripheral nerve sheath tumors with 3T proton MR spectroscopy

BACKGROUND AND PURPOSE

The characterization of peripheral nerve sheath tumors is challenging. The purpose here was to investigate the diagnostic value of quantitative proton MR spectroscopy at 3T for the characterization of peripheral nerve sheath tumors as benign or malignant, compared with PET.

MATERIALS AND METHODS

Twenty participants with 24 peripheral nerve sheath tumors underwent MR spectroscopy by use of a point-resolved sequence (TE, 135 ms). Six voxels were placed in 4 histologically proven malignant peripheral nerve sheath tumors and 22 voxels in 20 benign peripheral nerve sheath tumors (9 histologically proven, 11 with documented stability). The presence or absence of a trimethylamine signal was evaluated, the trimethylamine concentration estimated by use of phantom replacement methodology, and the trimethylamine fraction relative to Cr measured. MR spectroscopy results for benign and malignant peripheral nerve sheath tumors were compared by use of a Mann-Whitney test, and concordance or discordance with PET findings was recorded.

RESULTS

In all malignant tumors and in 9 of 18 benign peripheral nerve sheath tumors, a trimethylamine peak was detected, offering the presence of trimethylamine as a sensitive (100%), but not specific (50%), marker of malignant disease. Trimethylamine concentrations (2.2 ± 2.8 vs 6.6 ± 5.8 institutional units; P < .049) and the trimethylamine fraction (27 ± 42 vs 88 ± 22%; P < .012) were lower in benign than malignant peripheral nerve sheath tumors. A trimethylamine fraction threshold of 50% resulted in 100% sensitivity (95% CI, 58.0%-100%) and 72.2% (95% CI, 59.5%-75%) specificity for distinguishing benign from malignant disease. MR spectroscopy and PET results were concordant in 12 of 16 cases, (2 false-positive results for MR spectroscopy and PET each).

CONCLUSIONS

Quantitative measurement of trimethylamine concentration by use of MR spectroscopy is feasible in peripheral nerve sheath tumors and shows promise as a method for the differentiation of benign and malignant lesions. Trimethylamine presence within a peripheral nerve sheath tumor is a sensitive marker of malignant disease, but quantitative measurement of trimethylamine content is required to improve specificity.

State-of-the-art HR-US imaging findings of the most frequent musculoskeletal soft-tissue tumors

High resolution ultrasound (HR-US) including color Doppler ultrasound (CD-US), power Doppler ultrasound (PD-US), and spectral wave analysis (SWA), is a broadly available, non-invasive and relatively low-cost modality without ionizing radiation. It is increasingly used for initial assessment of an ambiguous musculoskeletal soft-tissue lesion and for sonographically guided core biopsy. The aim of this review is to provide sonographic findings of the most frequent benign and malign soft-tissue lesions. By this essay, we can show that combined with clinical features, with information on tumor-localization and patient age, many musculoskeletal lesions may be successfully characterized by HR-US. In contrast, a mere morphologic assignment of some fibrous tumors and malignant lesions remains often impossible; however, certain CD-US signs such as anarchic vascular architecture or arteriovenous shunting may be very helpful indicators for malignancy. HR-US offers a simple, quick, and reliable first-line examination of musculoskeletal soft-tissue lesions and may have an important role in the diagnostic work-up followed by magnetic resonance or multimodality imaging and guided core biopsy.

Soft-tissue masses in the shoulder girdle: an imaging perspective

We discuss the radiological assessment of soft-tissue masses presenting in the shoulder girdle and emphasise the relative strengths and weaknesses of the different imaging modalities available. The appearances of the common benign and malignant soft-tissue tumours are presented together with conditions that present with specific imaging features around the shoulder region.

Sonographic Evaluation of the Musculoskeletal Soft Tissue Masses

This article describes the sonographic appearance of a variety of soft tissue masses. We review the current indications for performing musculoskeletal sonography as a screening and diagnostic tool in the clinical management of soft tissue masses.