Case Report: Low-grade endometrial stromal sarcoma with intravenous and intracardiac extension: a case after misdiagnosis of endometrial stromal nodule as submucosal fibroid

We present herein a rare case of large vascular and cardiac metastases of low-grade endometrial stromal sarcoma (LG-ESS) in a female patient, which occurred after misdiagnosis of endometrial stromal nodule (ESN) as submucosal leiomyoma 7 years ago. Preoperative three-dimensional CT reconstruction was used to assess the extent of the lesion. The patient underwent radical resection: thrombectomy and total hysterectomy with bilateral salpingo-oophorectomy without establishing the cardiopulmonary bypass. Intraoperative transesophageal ultrasound (TEE) was used to monitor whether the intracardiac mass was removed completely. To date, this patient is alive without any evidence of recurrence 3 years after surgery. The differential diagnosis of ESN and LG-ESS is often difficult. A clear distinction can only be reliably made after histological analysis of the tumor's entire interface with the neighboring myometrium. This case highlights that follow-ups of patients with ESN are important. Regular follow-up can detect metastasis and recurrence of misdiagnosed LG-ESS as early as possible. Distant metastasis of LG-ESS is rare, especially involving large vessels or the heart. The treatment should largely rely on multidisciplinary cooperation. Although the surgery is traumatic, the perioperative mortality rate is low, and patients can avoid death from congestive heart failure or sudden death.

Update on Endometrial Stromal Tumours of the Uterus

Endometrial stromal tumours (ESTs) are rare, intriguing uterine mesenchymal neoplasms with variegated histopathological, immunohistochemical and molecular characteristics. Morphologically, ESTs resemble endometrial stromal cells in the proliferative phase of the menstrual cycle. In 1966 Norris and Taylor classified ESTs into benign and malignant categories according to the mitotic count. In the most recent classification by the WHO (2020), ESTs have been divided into four categories: Endometrial Stromal Nodules (ESNs), Low-Grade Endometrial Stromal Sarcomas (LG-ESSs), High-Grade Endometrial Stromal Sarcomas (HG-ESSs) and Undifferentiated Uterine Sarcomas (UUSs). ESNs are clinically benign. LG-ESSs are tumours of low malignant potential, often with indolent clinical behaviour, with some cases presented with a late recurrence after hysterectomy. HG-ESSs are tumours of high malignant potential with more aggressive clinical outcome. UUSs show high-grade morphological features with very aggressive clinical behavior. With the advent of molecular techniques, the morphological classification of ESTs can be integrated with molecular findings in enhanced classification of these tumours. In the future, the morphological and immunohistochemical features correlated with molecular categorisation of ESTs, will become a robust means to plan therapeutic decisions, especially in recurrences and metastatic disease. In this review, we summarise the morphological, immunohistochemical and molecular features of ESTs with particular reference to the most recent molecular findings.

Uterine Endometrial Stromal Tumors With Limited Infiltration: First Report of a Case Series Indicating Potential for Malignant Behavior

The distinction between a uterine endometrial stromal nodule (ESN) and low-grade endometrial stromal sarcoma (LGESS) is based on the nature of the interface between the lesion and the surrounding myometrium and the presence or absence of vascular invasion. Most LGESS exhibit widespread irregular myometrial invasion with or without vascular invasion, whereas ESNs are well-circumscribed without vascular invasion. Tavassoli and Norris proposed that minor marginal irregularity (up to 3 protrusions, each <3 mm beyond the main mass) is allowable in an ESN and these criteria have been incorporated into the World Health Organization Classification. There is a small group of neoplasms with marginal irregularity greater than that allowable in ESN but without the widespread myometrial infiltration typical of most LGESS. Such neoplasms have been categorized as endometrial stromal tumor with limited infiltration but there have been no studies which have provided follow-up in this group of neoplasms. We aimed to determine the clinical behavior of this uncommon group of neoplasms. From a series of 19 endometrial stromal tumors with limited infiltration, mainly from consultation practice, we obtained follow-up information in 16 cases by contacting referring pathologists and clinicians. The patient age ranged from 32 to 84 yr (median: 54 yr) and follow-up ranged from 16 to 187 mo (median: 52 mo). Two of 16 patients (12.5%) developed metastatic disease to the small intestine and peritoneum (1 case-metastasis at 23 mo) and bone and lung (1 case-humeral metastasis at 135 mo; lung and sacral metastases subsequently). No patient died from disease during the follow-up period. A small percentage of endometrial stromal tumors with limited infiltration exhibit malignant behavior with distant metastasis. Such neoplasms should be regarded as potentially malignant and the term LGESS with limited infiltration is an appropriate designation.

Endometrial Stromal Nodule: A Rarity and a Pathological Challenge

Endometrial stromal tumors are rare, and endometrial stromal nodule is the least common. In the region of Middle Jutland, Denmark, only two cases are reported since 1995. The nodules are benign; nevertheless, hysterectomy is the treatment of choice. Tumor margins are required for diagnosis and essential to differentiate it from an invasive stromal sarcoma whose prognosis is very different. We report a rare case of a 38-year-old woman, with presurgical diagnosis of a uterine tumor/polyp. She presented with nausea and changes in bleeding pattern and initially had a transcervical polyp resection performed. Histopathological examination showed the presence of an endometrial stromal tumor with unclear margins, and an invasive malignant endometrial sarcoma could not be excluded. Pathological examination revealed an endometrial stromal nodule with invasion, not exceeding three mm. Endometrial stromal tumors are interesting due to their rare existence and difficulties in establishing a histological diagnosis. Although endometrial stromal nodules are benign entities, they must be differentiated from the other invasive malignant stromal tumors, which may change the final prognosis. No preoperative diagnostic tools are at hand, and benign as well as malignant tumors are treated with hysterectomy.