Endometriosis is a condition defined by the presence of endometrial-like tissue growing outside the uterus, causing chronic pain and often affecting fertility. This tissue acts like the lining of the uterus, bleeding during the menstrual cycle and establishing lesions on the ovaries, fallopian tubes, and pelvic lining. The story of how this condition was finally understood medically is a complex historical journey, evolving from ancient theories to modern pathological identification.
Early Descriptions and Ancient Theories
Symptoms now associated with endometriosis, such as severe pelvic pain and infertility, were documented long before the underlying pathology was known. In ancient Greece, medical texts attributed to Hippocrates grouped gynecological distress under the term “hysteria.” This term is derived from the Greek word for uterus, hystera, reflecting the belief that the organ was the source of the ailments.
These early theories suggested the uterus was a mobile, animal-like entity that could “wander” if left unsatisfied, particularly if a woman remained childless. The “wandering womb” was thought to move throughout the body, causing various physical pains depending on its location. Such misinterpretations show how medical understanding was constrained by the prevailing anatomical and cultural knowledge of the time.
For centuries, intense menstrual pain was dismissed as psychological or attributed to vague concepts of imbalance, preventing any true understanding of the physical cause. The medical community lacked the tools to investigate the tissue-level source of the problem. This focus on symptoms and misdiagnosis persisted through the Middle Ages and into the early modern era.
The 19th-Century Anatomical Discovery
The transition from a symptom-based understanding to a pathological one began in the 19th century, driven by advances in microscopy and surgical pathology. This era marked a shift when physicians began looking at tissue samples to identify the physical cause of disease. The first recorded pathological description of ectopic endometrial tissue was made in 1860 by the German pathologist Karl von Rokitansky.
Rokitansky described endometrial glands and stroma embedded within the muscular wall of the uterus, a condition he termed “cystosarcoma adenoids uterinum.” This condition, now known as adenomyosis, represents the first anatomical recognition of misplaced uterine lining cells. However, tissue found outside the uterus was not yet clearly distinguished or named as a separate disease entity.
At the turn of the 20th century, Thomas Stephen Cullen provided a more systematic description of these “adenomyomas,” including their presence in areas like the rectovaginal septum. Cullen detailed how the uterine mucosa seemed to invade the underlying tissue, offering a clearer picture of the ectopic tissue’s characteristics. Despite these significant observations, the condition was still referred to by various descriptive names like “adenoma” or “heterotopia.”
Coining the Term and Establishing Modern Criteria
The formal establishment of the condition as a distinct disease entity occurred in the early 20th century, thanks to the systematic work of American gynecologist John A. Sampson. Sampson is credited with coining the term “endometriosis” in the 1920s, providing a specific name for the condition. This naming was a decisive step, moving the condition beyond vague pathological descriptions toward a clinical diagnosis.
In 1927, Sampson published his influential theory of “retrograde menstruation” to explain the origin of the disease. This theory proposed that viable endometrial tissue flows backward through the fallopian tubes into the pelvic cavity, where it implants and grows. This mechanism, though not the sole explanation for all cases, provided the first major pathological framework for understanding tissue migration.
Sampson’s work formalized the condition, leading to the development of modern diagnostic criteria and research efforts. While endometriotic cysts had been described earlier, Sampson’s comprehensive study systematically detailed the clinical manifestations and pathogenesis. The shift to a specific, named disease marked the beginning of the modern medical fight against endometriosis.