Ureteral Endometriosis - A Clinicopathological Overview

Introduction

Menstrual disorders are the most common types of gynecological disorders. Endometriosis is a rare type of gynecological condition caused by the implantation of endometrium in other sites. In some conditions, this implantation may occur in the renal system, which leads to renal complications.

What Is Endometriosis?

Around 190 million women of reproductive age suffer from endometriosis worldwide. This chronic inflammatory condition is characterized by the presence of endometrium-like (innermost lining of the uterus) tissue outside the uterus. These tissue-like structures can be found in genital structures like fallopian tubes, vagina, ovaries, and uterosacral ligament (tissue that connects the lower part of the uterus to the ligament) and the outer surface of the uterus. These tissues can also be found in extragenital structures like the gastrointestinal tract, pleura, pericardium, rectum, or central nervous system.

What Are the Causes of Endometriosis?

The causes associated with these conditions are unknown. According to some researchers, genetic factors are crucial in this condition. Genes such as WNT4, ZNF366, FN1, and GERB 1 are associated with this condition. Several others have put forward different hypotheses. These are:

• Retrograde Menstruation - This theory is proposed by Sampson. According to this theory, during the menstrual cycle, blood products and cells of the menstrual cycle flow backward from the Fallopian tubes to the peritoneum. This is mainly seen in patients with open fallopian tubes. These cells are implanted in the deep tissue sites and grow and form endometrial tissues.

• Lymphatic and Vascular Metastasis Theory - According to the theory by Meyer, the parietal peritoneum epithelium (layer of the abdominal cavity) is stimulated by several factors like cytokines and growth factors. These cells differentiate and form endometrial cells. Stem cells of bone marrow may give rise to endometriosis.

As a result of these factors, the body's systemic response is altered. Persons suffering from endometriosis show higher levels of estrogen and lower levels of progesterone. Also, a high amount of pro-inflammatory mediators can be observed due to the activation of the cyclooxygenase-2 pathway.

What Are the Symptoms of Endometriosis?

The clinical presentation of endometriosis are:

1. Dysmenorrhea: Patients complain of severe pain in the lower back region during periods. Pain may persist even before or after the period. Sometimes it is associated with severe cramping of the abdomen.

2. Menorrhagia: Patients often suffer from abnormally heavy bleeding during period days. But in some cases, inconsistent bleeding is also noticed.

3. Dysuria: Pain during urination and during bowel movements.

4. Dyspareunia: Pain during intercourse is also associated with this.

5. Patients suffer from several mental disorders like frequent mood swings, depression, anxiety, and fatigue.

What Is Urethral Endometriosis?

Urethral endometriosis is a rare phenomenon. It is seen in 0.1 to 0.4 percent of cases of endometriosis. Ureter is the second most common site for renal endometriosis following endometriosis of the urinary bladder. The first case of urethral endometriosis was described by Cullen in 1917. So far, only 150 cases are being documented. The distal segment of the left ureter is most commonly involved.

Pathogenesis:

The exact pathogenesis of this disease is not known. But according to some research, endometriosis is developed from the retroperitoneum. In some cases, embryonic remains of the Mullerian duct (the embryonic structure that helps in the development of female genital organs) present in the retroperitoneum become stimulated and form endometrium-like tissues. According to others, the left sigmoid colon and microenvironment created by this plays a crucial role in the formation of urethral endometriosis. The position of the left sigmoid colon prevents the immune cells from reaching endometrial cells coming from the left fallopian tube into the peritoneal environment. As a result, the endometrial cells are implanted, which leads to the formation of urethral endometriosis.

There are two pathological types of urethral endometriosis. In the extrinsic type, glandular and stromal overgrowth can be seen in the submucosal region. Intrinsic endometriosis is the less common type which involves the uroepithelial and submucosal layers.

Symptoms:

Typical symptoms of endometriosis, like pain in the lower abdomen during periods, pain during urination, and abnormal bleeding during periods, are present. Apart from this, symptoms like blood in the urine are seen in almost 15 percent of cases. Other abnormal symptoms are:

• Inconsistent urination. Patients often complain of the fullness of the bladder even after urination.

• Decreased urinary output.

• Frequent urination at night time, especially during sleeping.

• Inability to start urine flow. Patients often complain of the absence of a urine stream.

All these symptoms are caused by the mechanical obstruction of the urinary bladder.

What Are the Diagnostic Processes of Urethral Endometriosis?

The diagnostic procedure for urethral endometriosis are:

1. Magnetic Resonance Imaging (MRI): It is one of the most commonly used imaging methods for the detection of extension of the disorder. This technique can be used to differentiate between extrinsic and intrinsic forms.

2. Ureteroscopy: In this procedure, direct visualization inside ureters and kidneys is possible. This is also helpful in collecting histological samples.

3. Other than this, abdominal and vaginal ultrasound can be used for the detection of abnormal tissue growth.

What Are the Treatment Options?

The treatment options in such cases are:

1. In the early stages of the disease, hormonal therapy can be used. Such treatment options are helpful for women of childbearing age. The hormonal therapy includes the use of the estrogen-progestin combination (Medroxyprogesterone) and progestin alone. In some cases, GnRH agonists (Leuprolide and Goserelin) can also be used. Local application of progesterone with the help of an intrauterine levonorgestrel device can also be done.

2. Uteroscopic techniques include surgical removal of the affected area with the help of laser ablation. Also, balloon dilation with stent placement can also be done with this technique.

3. Ureterolysis is done in extrinsic cases of urethral endometriosis where the size of the lesion is less than 3 millimeters. This procedure is contraindicated in cases of intrinsic urethral endometriosis.

4. For extensive cases, surgical removal of tissue with laparotomy is done.

5. Ureteral resection with ureteral reconstruction can be done in cases of intrinsic endometriosis. In such cases, the size of the lesion is more than three centimeters situated below the level of the iliac vessels and hydroureteronephrosis. In such procedures, ureteral-ureteral anastomosis (end-to-end joining of two segments of the ureter) can be done where the ureteral stenosis is limited to the ovarian fossa. In cases where ureteral stenosis is close to the vesicoureteral junction, procedures like ureteroneocystostomy (implantation of the ureter into the bladder) can be performed.

Conclusion

Endometriosis is a chronic inflammatory condition caused by hormonal dysregulation. Implantation of endometrial tissue may cause various gynecological problems. In some rare cases, tissues may be implanted into the urinary bladder. Patients suffering from such conditions may complain of urinary problems. Such cases can be treated by hormonal therapy and surgical excision.