A case of low-grade endometrial stromal sarcoma presented as an intramyometrial mass mimicking uterine leiomyoma on MRI.

A low-grade endometrial stromal sarcoma (ESS) has a pattern of presenting as an intramyometrial mass and is often misdiagnosed as cellular leiomyoma or degenerative uterine leiomyoma. A low-grade ESS is a malignant tumour that requires total hysterectomy with bilateral salpingo-oophorectomy; while a leiomyoma is a benign tumour and could be acceptable for enucleation. As the treatment strategies differ between a low-grade ESS and leiomyoma, radiologists should be familiar with the characteristic MRI findings of a low-grade ESS. A 51-year-old woman with abnormal uterine bleeding had been observed for 2 years at a previous hospital for a uterine leiomyoma based on MRI findings. A contrast-enhanced MRI demonstrated an intramyometrial mass composed of three components with the hypointense rim on T2-weighted images (T2WI): the first component was a homogeneous solid structure with mild hyperintensity on T2WI with a low apparent diffusion coefficient value; the second component was cystic; the third component was a structure of low signal intensity on T2WI similar to the muscle. Although a degenerative uterine leiomyoma was a differential diagnosis, these MRI findings were suggestive of a low-grade ESS. A total abdominal hysterectomy, bilateral salpingo-oophorectomy, pelvic lymphadenectomy, and partial omentectomy were performed. The pathological diagnosis was a low-grade ESS. In a low-grade ESS, there are three major patterns of MRI findings: one of these patterns is the less popular but clinically important intramyometrial mass pattern, which can be misdiagnosed as a leiomyoma, and this case conformed to this pattern.

Laryngeal schwannoma with extralaryngeal extension mimicking a thyroid tumour.

Objective: A schwannoma is a common benign tumour that can arise anywhere in the body. When it occurs in an unusual location such as the larynx, its differentiation from other tumours can be challenging. Herein, we report a case of a laryngeal schwannoma with extralaryngeal extension that mimicked a thyroid tumour, focusing on its characteristic features on MRI. Methods: A 19-year-old male presented with a mass in the left side of the neck and hoarseness for 2 years. Endoscopy showed a submucosal mass in the laryngeal region. MRI found a well-defined solid mass in the thyroid gland, extending to the larynx through the lower edge of the thyroid cartilage. T 2 weighted MRI showed slightly low signal intensity at the central part of the tumour and high signal intensity at the peripheral part of the tumour. Pre-operative imaging suggested that the tumour originated in the thyroid gland. Left thyroidectomy with tumour excision was performed; the tumour was diagnosed as a laryngeal schwannoma with extralaryngeal extension, compressing the thyroid gland. In retrospect, features such as the dumbbell-shape and known as 'target sign' on T 2 weighted MRI were typical features of schwannoma. Additionally, the tumour's extension pattern was similar to previous reports of laryngeal schwannomas with extralaryngeal extension. Conclusion: A large laryngeal schwannoma may extend outside the larynx with significant compression of the thyroid gland. Understanding the pattern of extension and familiarity with the features on MRI can improve the preoperative diagnosis accuracy.