Stromal sarcoma is a rare cancer that originates in the connective tissues, known as the stroma, found throughout the body.
Understanding Stromal Sarcoma
Stromal sarcoma is a malignant tumor arising from mesenchymal cells within the body’s connective tissues. While it can occur in various locations, endometrial stromal sarcoma (ESS), which develops in the inner lining of the uterus, is the most frequently encountered form. ESS represents a small percentage of all uterine malignancies, accounting for approximately 0.2% to 1% of uterine cancers.
Endometrial stromal sarcomas are classified based on how aggressive their cells appear under a microscope. Low-grade ESS (LG-ESS) is characterized by cells that resemble normal endometrial stromal cells and tend to grow slowly, often infiltrating the uterine muscle wall in a worm-like pattern. High-grade ESS (HG-ESS) involves cancer cells that look more abnormal and divide more rapidly. Undifferentiated uterine sarcoma is a highly aggressive form with significant cellular atypia and high mitotic activity, often including areas of necrosis.
Recognizing the Signs
Symptoms of stromal sarcoma vary based on the tumor’s location and are often non-specific. For endometrial stromal sarcoma, common signs include abnormal vaginal bleeding, such as bleeding between periods, heavier menstrual flow, or bleeding after menopause. Some individuals might also experience unusual vaginal discharge.
Pelvic pain or pressure and abdominal swelling are additional symptoms that can arise from uterine stromal sarcoma. When stromal sarcoma develops in other parts of the body, a palpable mass may be noticed, accompanied by localized pain, swelling, or issues with organ function depending on the affected area. Given the non-specific nature of these symptoms, it is advisable to seek medical evaluation for any persistent or concerning signs.
Diagnostic Approaches
Diagnosing stromal sarcoma typically begins with a thorough medical history and physical examination, including a pelvic exam if uterine involvement is suspected. Imaging techniques play a role in identifying suspicious masses and assessing their extent. A transvaginal ultrasound provides clear images of the uterus.
Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scans are also used to visualize tumors and determine if the cancer has spread. A definitive diagnosis of stromal sarcoma relies on a tissue biopsy, where a small sample of the suspicious tissue is removed for examination. For uterine stromal sarcoma, this may involve a hysteroscopy with a biopsy or a dilation and curettage (D&C) procedure. Pathologists then analyze the tissue sample under a microscope to confirm the diagnosis, classify the specific type of stromal sarcoma, and assess its grade. Immunohistochemistry, a laboratory technique, further aids in differentiating ESS from other uterine tumors by identifying specific protein expressions like estrogen receptor (ER), progesterone receptor (PR), and CD10.
Treatment Strategies
The primary treatment for stromal sarcoma often involves surgical removal of the tumor. For uterine endometrial stromal sarcomas, this typically means a total hysterectomy (removal of the uterus) and a bilateral salpingo-oophorectomy (removal of both fallopian tubes and ovaries). In select cases of low-grade endometrial stromal sarcoma, particularly in younger individuals desiring future pregnancy, fertility-sparing surgery may be considered.
Radiation therapy may be used as an adjuvant treatment after surgery to reduce the risk of local recurrence or for local disease control, especially in advanced cases or if complete surgical removal is not possible. Chemotherapy, which uses drugs to target rapidly dividing cells, is typically reserved for high-grade or advanced stromal sarcomas that have spread. Combinations of chemotherapy drugs, such as gemcitabine and docetaxel, are sometimes employed.
Hormonal therapy is a significant treatment option for certain types of stromal sarcoma, particularly low-grade endometrial stromal sarcomas, due to their hormone receptor status. These therapies, including progestins, aromatase inhibitors (like letrozole, anastrozole, and exemestrum), and gonadotropin-releasing hormone (GnRH) analogues, work by altering hormone levels to slow tumor growth. Targeted therapies represent a newer approach, focusing on specific molecular pathways involved in cancer growth, with ongoing research exploring their role in various stromal sarcoma subtypes. Treatment decisions for stromal sarcoma are complex and are generally made by a multidisciplinary team of specialists to tailor the approach to the individual patient’s specific circumstances.