The value of clinical parameters combined with magnetic resonance imaging (MRI) features for preoperatively distinguishing different subtypes of uterine sarcomas: An observational study (STROBE compliant)

Sonographic and Magnetic Resonance Characteristics of Gynecological Sarcoma

INTRODUCTION

Gynecological sarcomas are rare malignant tumors with an incidence of 1.5-3/100,000 and are 3-9% of all malignant uterine tumors. The preoperative differentiation between sarcoma and myoma becomes increasingly important with the development of minimally invasive treatments for myomas, as this means undertreatment for sarcoma. There are currently no reliable laboratory tests or imaging-characteristics to detect sarcomas. The objective of this article is to gain an overview of sarcoma US/MRI characteristics and assess their accuracy for preoperative diagnosis.

METHODS

A systematic literature review was performed and 12 studies on ultrasound and 21 studies on MRI were included.

RESULTS

For the ultrasound, these key features were gathered: solid tumor > 8 cm, unsharp borders, heterogeneous echogenicity, no acoustic shadowing, rich vascularization, and cystic changes within. For the MRI, these key features were gathered: irregular borders; heterogeneous; high signal on T2WI intensity; and hemorrhagic and necrotic changes, with central non-enhancement, hyperintensity on DWI, and low values for ADC.

CONCLUSIONS

These features are supported by the current literature. In retrospective analyses, the ultrasound did not show a sufficient accuracy for diagnosing sarcoma preoperatively and could also not differentiate between the different subtypes. The MRI showed mixed results: various studies achieved high sensitivities in their analysis, when combining multiple characteristics. Overall, these findings need further verification in prospective studies with larger study populations.

Methodological considerations on segmenting rhabdomyosarcoma with diffusion-weighted imaging-What can we do better?

PURPOSE

Diffusion-weighted MRI is a promising technique to monitor response to treatment in pediatric rhabdomyosarcoma. However, its validation in clinical practice remains challenging. This study aims to investigate how the tumor segmentation strategy can affect the apparent diffusion coefficient (ADC) measured in pediatric rhabdomyosarcoma.

MATERIALS AND METHODS

A literature review was performed in PubMed using search terms relating to MRI and sarcomas to identify commonly applied segmentation strategies. Seventy-six articles were included, and their presented segmentation methods were evaluated. Commonly reported segmentation strategies were then evaluated on diffusion-weighted imaging of five pediatric rhabdomyosarcoma patients to assess their impact on ADC.

RESULTS

We found that studies applied different segmentation strategies to define the shape of the region of interest (ROI)(outline 60%, circular ROI 27%), to define the segmentation volume (2D 44%, multislice 9%, 3D 21%), and to define the segmentation area (excludes edge 7%, excludes other region 19%, specific area 27%, whole tumor 48%). In addition, details of the segmentation strategy are often unreported. When implementing and comparing these strategies on in-house data, we found that excluding necrotic, cystic, and hemorrhagic areas from segmentations resulted in on average 5.6% lower mean ADC. Additionally, the slice location used in 2D segmentation methods could affect ADC by as much as 66%.

CONCLUSION

Diffusion-weighted MRI studies in pediatric sarcoma currently employ a variety of segmentation methods. Our study shows that different segmentation strategies can result in vastly different ADC measurements, highlighting the importance to further investigate and standardize segmentation.

Ultrasound features of highly vascularized uterine myomas (uterine smooth muscle tumors) and correlation with histopathology

OBJECTIVE

To correlate the ultrasound appearance of highly vascularized uterine myomas with their histopathological diagnosis.

METHODS

This was a prospective observational study of patients with a preoperative ultrasound diagnosis of a highly vascularized uterine myoma (color score of 3 or 4, according to the Morphological Uterus Sonographic Assessment (MUSA) criteria), characterized by circumferential and intralesional vascular pattern, who underwent myomectomy or hysterectomy. For each patient, ultrasound characteristics were recorded at baseline, including the number of lesions, the size, echogenicity and border regularity of the lesion, presence of cystic areas and shadowing within the myoma, and visualization of the endometrium. Ultrasound features were correlated with the definitive histological diagnosis. Ultrasound features were then compared between malignant and benign lesions.

RESULTS

We included 70 patients with highly vascularized uterine myomas on power/color Doppler. Their mean age was 46.5 ± 11.4 years and 13 (18.6%) were postmenopausal. At histological examination, 65 (92.9%) uterine myomas were benign lesions, comprising 32 typical leiomyomas, 29 leiomyoma variants and four adenomyomas. The remaining five (7.1%) uterine myomas were malignant masses, comprising two uterine sarcomas, one leiomyosarcoma, one neuroendocrine tumor and one uterine smooth muscle tumor of uncertain malignant potential (STUMP). The mean age of patients with a malignant lesion was significantly higher than the age of those with a benign lesion (64.8 ± 16.0 vs 42.4 ± 5.1; P < 0.001). Four out of five patients with a malignant lesion were over 45 years old. Ultrasound demonstrated cystic areas within the lesion in 10/32 (31.3%) typical leiomyomas, 16/29 (55.2%) leiomyoma variants, all four adenomyomas and in the cases of STUMP and leiomyosarcoma. Lesion borders were regular in 64/65 (98.5%) benign lesions and 2/5 (40%) malignant lesions (P < 0.05). No significant differences were observed between benign and malignant lesions with respect to echogenicity, presence of shadowing and size. The endometrium was visible in 55/65 women with benign lesions and in 2/5 with malignant lesions (P = 0.03).

CONCLUSIONS

Our results showed that ultrasound features of uterine myomas, such as circumferential and intralesional vascularity, cystic areas and lesion borders, are important parameters for differential diagnosis, especially when combined with the patient's age. Such features could be useful to differentiate typical myomas from benign variants and malignant lesions in a preoperative setting and to select patients that may benefit from conservative management rather than surgery. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

MR Imaging of uterine sarcomas: a comprehensive review with radiologic-pathologic correlation

The aim of this article is to summarize the MRI features of each sarcoma subtype and to correlate them with its pathological findings. Literature review through PubMed/Medline database to identify relevant articles on uterine sarcomas, with a special emphasis on their MRI findings and pathological features. While several, more generalistic, MRI findings of a uterine tumour should raise suspicion for malignancy (including irregular contour, intra-tumoral necrosis/hemorrhage and low ADC values), some particular features may suggest their specific histological subtype such as the gross lymphovascular invasion associated with endometrial stromal sarcomas, the "bag of worms" appearance of the low-grade endometrial stromal sarcoma and the "lattice-like" aspect of adenosarcomas which results from the mixed composition of solid and multiseptated cystic components. Knowledge of the different histological uterine sarcoma subtypes, their specific MRI features and comprehension of their pathological background allows for a more confident diagnosis and may indicate the correct histological subtype.

Benign Uterine Disease: The Added Role of Imaging

Benign uterine diseases are very common gynecologic conditions that affect women mostly in reproductive age. Ultrasound examination is the first-line imaging technique, but MRI is more accurate for diagnosis, characterization, and patient management. In this review, we especially highlight the added value of MRI in the diagnosis of benign uterine disease, discuss their imaging characteristics, and describe the therapeutic options and the added value of MRI in the treatment planning.