|Year : 2018 | Volume
| Issue : 2 | Page : 251-253
Low-grade endometrial stromal sarcoma: A report of five cases
Saba Bashir, Prema Saldanha
Department of Pathology, Yenepoya Medical College, Mangalore, Karnataka, India
|Date of Web Publication||27-Dec-2018|
Dr. Saba Bashir
Department of Pathology, Yenepoya Medical College, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
Endometrial stromal sarcoma (ESS) is a very rare uterine tumor, composed of cells resembling endometrial stromal cells. As these tumors have indistinct clinical and radiological features, they are very rarely diagnosed preoperatively. We are reporting a series of five cases clinically mistaken as benign masses. The age range of these patients was 38–65 years, with a mean age of 49 years. The patients presented with vaginal bleeding, lower abdominal pain, and abdominal mass. All the cases were clinically diagnosed on ultrasound as leiomyoma and underwent total abdominal hysterectomy. Microscopically, all the cases showed a densely cellular tumor composed of small oval cells bearing a close resemblance to normal endometrial stromal cells and were diagnosed as low-grade ESS. This is an aggressive tumor but has a better prognosis in early stage.
Keywords: Endometrial stromal sarcoma, low grade, uterus
|How to cite this article:|
Bashir S, Saldanha P. Low-grade endometrial stromal sarcoma: A report of five cases. Arch Med Health Sci 2018;6:251-3
| Introduction|| |
Endometrial stromal sarcomas (ESS) are malignant tumors of the uterus. They are composed of neoplastic cells resembling normal proliferative endometrial stromal cells. The latest WHO classification divides endometrial stromal tumors into four categories based on morphologic features: endometrial stromal nodule (ESN) (benign), low-grade ESS (LGESS), high-grade ESS (HGESS), and undifferentiated ESS. Of these, LGESS accounts for <1% of all uterine malignancies. The frequency of HGESS and undifferentiated ESS is unknown. LGESS tends to occur in middle-aged women (average age of 45 years). The clinical recognition of LGESS may be difficult, as it is frequently misdiagnosed as a benign lesion like leiomyoma or endometrial polyp and is mostly revealed on histopathological examination postoperatively.
| Case Report|| |
We encountered five cases of LGESS, the clinical details of which are shown in [Table 1].
The tumors were large in size ranging from 8 to 15 cm in greatest dimension. The cut surfaces ranged from pale white to pale brown [Figure 1].
|Figure 1: Enlarged uterus on cut surface showing pale white intramural fleshy mass|
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Microscopically, all the cases showed a densely cellular tumor composed of small oval cells bearing a close resemblance to normal endometrial stromal cells [Figure 2] and [Figure 3]a, [Figure 3]b. Small arterioles were seen within the tumor. Two cases showed occasional mitotic figures and one case also showed mild nuclear atypia and apoptotic bodies.
|Figure 2: Low-grade endometrial stromal sarcomas: The tumor cells resemble the cells of normal proliferative phase endometrial stroma (H and E, ×10). Inset: Uniform small oval tumor cells with minimal nuclear atypia (H and E, ×40)|
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|Figure 3: (a and b) Irregular sized and shaped island of cells permeating the myometrium tissue (H and E, ×4, ×10)|
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In one case, cytological examination of the ascitic fluid showed fairly uniform small-to-medium-sized cells with round-to-oval nuclei, fine nuclear chromatin, occasional nucleoli, and scant cytoplasm [Figure 4]. With this cytological picture, a malignant tumor was diagnosed and possibility of ESS was considered.
|Figure 4: Ascitic fluid showing uniform small-to-medium-sized cells in sheets and groups. Inset: small-to-medium cells with round-to-oval nuclei, fine nuclear chromatin, occasional nucleoli and scant cytoplasm|
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| Discussion|| |
LGESS are very rare malignant tumors that form <1% of all uterine malignancies. They resemble endometrial stromal cells in the proliferative stage.
ESS affects younger women and the mean age is 42–58 years. The clinical presentation of ESS is abnormal uterine bleeding that occurs in about 90% of women and 70% cases show uterine enlargement. Most tumors grow through the intramural sections of the uterus rather than intra cavitary, hence making it difficult for preoperative histopathology diagnosis. A few series of cases [Table 2] have been reported which showed a similar age group and clinical presentation. Most of the tumors in these series were also large.
|Table 2: Comparison of similar studies of low-grade endometrial stromal sarcoma|
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The ESN and LGESS fall in the lower end of the spectrum of this group of tumors. Both are typically composed of a diffuse growth of small blue cells with scant cytoplasm, and oval-to-spindle nuclei that resemble the endometrial stromal cells of the proliferative endometrium. The “tongue-like” patterns of myometrial and lymphovascular invasion are classical histological features that are important in the distinction from ESN. HGESS is characterized by a monomorphic proliferation of round cells in a vaguely nested or pseudoglandular pattern. About half of the tumors are biphasic, where the round-cell component is admixed with an LGESS-like component that is usually fibrous or fibromyxoid. Undifferentiated uterine sarcoma represents a high-grade sarcoma that lacks specific differentiation and bears no histological resemblance to endometrial stroma.
Diagnosis of LGESS is usually made postoperatively in most instances by histopathological examination since in majority of cases a preoperative clinical diagnosis of leiomyoma is made.
It is essential to diagnose it early because of its poor prognosis and metastatic potential. Therefore, in all cases of abnormal uterine bleeding, a strong clinical suspicion is recommended for better management. About one-third to one-half of patients with ESS develop recurrences, usually limited to the pelvis and lower genital tract. Distant metastasis to lungs may occur after several years.
The differential diagnosis of LGESS includes ESN, cellular leiomyoma, cellular intravenous leiomyomatosis, cellular endometrial polyp, and various soft-tissue neoplasms.
In cases where histopathology is not diagnostic, immunomarkers such as desmin, h-caldesmon, oxytocin receptors, CD10, and inhibin are useful. Cellular leiomyomas express h-caldesmon, desmin, and oxytocin receptors, while CD10 and inhibin expression is a feature of ESS. Strong and diffuse CD10 staining is observed in ESN and LGESS, whereas most leiomyomas were negative.
| Conclusion|| |
LGESS is an aggressive tumor but has a better prognosis in early stage. Clinically, it is not usually apparent and often mistaken as a benign lesion.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]