Stages of Endometriosis

Endometriosis is classified into four stages (minimal, mild, moderate, and severe) based on lesion size, depth, and spread.

• The disease’s location,
• The extent and depth of endometriosis implants,
• The presence and size of ovarian endometriomas,
• The presence and severity of adhesions.

How are stages assigned?

The criteria that make up the stages of endometriosis are graded on a point system to determine classification. First developed in 1973, the classification scheme has been revised and refined three times for a more precise method of documentation. A score of 1-15 indicates minimal or mild endometriosis. A score of 16 or higher indicates moderate to severe endometriosis.

• Stage 1 (minimal) involves a few small, shallow implants with little to no scar tissue.
• Stage 2 (mild) includes more and slightly deeper lesions.
• In stage 3 (moderate), implants are deeper, with some scar tissue and possibly small ovarian cysts.
• Stage 4 (severe) features widespread lesions, large cysts, and dense adhesions affecting multiple pelvic organs.

Staging helps guide treatment but doesn’t always reflect symptom severity. Even minimal endometriosis can cause significant pain or infertility. Laparoscopy is the standard method for accurate staging and diagnosis.

What is the problem with this method of classification?

The scoring and stage of the disease are not indicative of the level of pain the patient experiences. Instead, this system was fundamentally developed as an indicator of endometriosis-associated infertility, and, therefore, has no specific correlation with any symptoms. This means that a woman in stage IV can be asymptomatic, while a stage 1 patient might be in debilitating pain.

How do I know what stage my endometriosis is?

You can only definitively confirm your endometriosis stage through a surgical procedure known as laparoscopy. Doctors cannot diagnose the exact stage using only physical exams, blood tests, or standard imaging scans. During this surgery, a specialist inserts a camera to visually inspect the location and depth of implants.

They evaluate the size of the tissue and look for any scar tissue or adhesions on organs. Based on a standard scoring system from these findings, they classify the disease from Stage I to IV. It is crucial to remember that the severity of your pain does not indicate your stage.

Stages of endometriosis and their symptoms

The Characteristics of Stage 1 Minimal Endometriosis

The first stage of endometriosis is classified as minimal and represents the earliest or least physically intrusive form of the disease. In this phase the endometrial implants are small, few in number and located superficially on the pelvic organs or the lining of the pelvis. These lesions are often described as isolated implants that have not yet created significant scar tissue or adhesions between organs. Visually these implants can vary in appearance looking like small red, white or clear blisters on the surface of the tissue. Because they are superficial they have not burrowed deep into the organ structures which theoretically makes them easier to remove during surgery.

However the term minimal can be incredibly misleading when it comes to the patient experience of pain. These small and active lesions produce inflammatory chemicals known as prostaglandins which irritate the surrounding nerves and cause intense cramping or pelvic pain. The body reacts to these small invaders with a strong immune response which contributes to the sensation of pain and fatigue. Diagnosis at this stage can be difficult because these small lesions rarely show up on standard imaging tests like ultrasounds or MRIs. They are often only visible to the surgeon’s eye during a laparoscopic exploration. Treating stage one often focuses on pain management and suppressing the menstrual cycle to prevent the lesions from growing or spreading further.

Progression to Stage 2 Mild Endometriosis

As the disease progresses to stage two it is categorized as mild endometriosis which indicates a slightly higher number of implants and a deeper level of tissue invasion. At this point the lesions are no longer just sitting on the surface but have started to root themselves into the pelvic lining or the surface of the ovaries. The total area covered by the disease is larger than in stage one and there may be some very minor scarring present. The structural integrity of the pelvic organs is usually still intact meaning the ovaries and tubes are not stuck together or distorted.

The symptoms experienced in stage two are often similar to stage one but may occur with greater frequency or intensity depending on where the lesions are located. If an implant is located near the bowel or the bladder the patient might start to experience specific pain associated with urination or bowel movements during their period. The risk of infertility begins to rise slightly in this stage not necessarily because of structural blockage but because the inflammatory environment in the pelvis can be toxic to eggs and sperm. Surgical intervention at this stage involves excising or ablating these deeper implants to provide relief and improve the environment for conception.

The Turning Point of Stage 3 Moderate Endometriosis

Stage three represents a significant escalation in the disease and is termed moderate endometriosis. The defining feature of this stage is the presence of deep implants and the formation of endometriomas which are cysts filled with old, dark blood found on the ovaries. These cysts are frequently referred to as chocolate cysts because of the thick, brown tar like fluid inside them. Alongside these cysts there are usually more extensive adhesions which are bands of scar tissue that can cause organs to stick together.

At this stage the anatomy of the pelvis may begin to distort as adhesions pull the ovaries or tubes out of their natural position. The presence of ovarian cysts is a major concern for fertility as they can damage healthy ovarian tissue and interfere with ovulation. Pain at this stage can be chronic and not just limited to the menstrual cycle because the cysts take up space and put constant pressure on surrounding structures. Diagnosing stage three is often easier than the earlier stages because ovarian cysts are usually visible on a high quality transvaginal ultrasound. Treatment often becomes more aggressive involving the surgical removal of cysts while trying to preserve as much healthy ovarian reserve as possible.

The Complexity of Stage 4 Severe Endometriosis

The final classification is stage four or severe endometriosis which is characterized by deep and widespread implants, large ovarian cysts and dense adhesions. In this advanced state the pelvic anatomy is often severely distorted causing what doctors describe as a frozen pelvis. This means the pelvic organs including the uterus, ovaries, bowel and bladder are firmly stuck together by scar tissue and cannot move freely. The fallopian tubes may be blocked or damaged which presents a significant mechanical barrier to natural conception.

This stage requires the most skilled surgical management because the disease often infiltrates vital structures like the bowel or the ureters. Removing the disease without damaging these organs requires a multidisciplinary team often including colorectal surgeons or urologists. Despite the severity of the internal damage some women with stage four disease experience manageable pain while others suffer from constant agony. The primary goals of treatment shift towards restoring anatomy, preserving organ function and often utilizing assisted reproductive technologies like IVF if pregnancy is desired.

Our Approach

What is the best way to obtain a thorough classification?

For an accurate diagnosis, it is necessary to conduct a direct visual inspection inside the pelvis and abdomen, as well as a tissue biopsy of the implants. A pathologist will observe the obtained biopsy sample under a microscope in order to view any inflammatory changes or signs of cancer, which they will then report back to the surgeon. This ultimately allows your surgeon to gain a better understanding of the extent of your disease and thus provide a more descriptive classification of your particular case of endometriosis.

What is our “descriptive classifications of endometriosis?”

Due to the factors mentioned above, your normal I through IV classification of endometriosis may be of less significance than our descriptive classifications. We define four different forms of the disease that must be considered: peritoneal disease, ovarian endometrioma, deep infiltrating endometriosis (DIE), and frozen pelvis. Though different, they are not altogether clinically distinct, and the pathophysiological mechanisms involved in all four forms remain poorly understood.

It is crucial to monitor and keep in mind the extent of your symptoms and the disease itself. Sometimes patients feel they need to mask their suffering, and it is incredibly disheartening and incorrect when their physician proceeds to tell them their pain is simply “emotional stress.” We believe that you deserve the care and attention that a complicated disease such as endometriosis deserves. This includes having honest discussions about the extent of the symptoms you may be experiencing.

Author
Tamer Seckin, MD
Date: May 20, 2020

Dr. Seckin is an endometriosis specialist and women’s reproductive health advocate. He has been in private practice for over 30 years at Lenox Hill Hospital with a team of highly skilled personnel.

Dr. Seckin specializes in advanced laparoscopic procedures and is recognized for his expertise in complex cases of deep infiltrating endometriosis of the pelvis. He is particularly dedicated to performing fertility-preserving surgeries on cases involving the ovaries.

He has developed patented surgical techniques, most notably the “Aqua Blue Excision” technique for a better visualization of endometriosis lesions. His surgical techniques are based on precision and microsurgery, emphasizing organ and fertility preservation, and adhesion and pain prevention.

Dr. Seckin is considered a pioneer and advocate in the field of endometriosis.