Porth's Essentials of Pathophysiology, 4e

1031

Disorders of the Female Genitourinary System

C h a p t e r 4 0

Umbilicus

Ovary

Small bowel

Colon

Fallopian tube

Uterine serosa

Rectouterine pouch

Peritoneum

Bladder

Uterovesical fold

FIGURE 40-10. Common locations of endometriosis in the pelvis and abdomen.

to five decades. Approximately 5% to 10% of repro- ductive-age women have some degree of endometrio- sis. 28,30 Risk factors may include early menarche and late menopause; short menstrual cycles (<28 days), lon- ger duration (>5 days) or heavier flow cycles; increased menstrual pain; and other first-degree relatives with the condition. Several theories attempt to explain the origin of the dispersed endometrial lesions that occur in women with endometriosis. 6,7,28 One theory, the regurgitation/implan- tation theory , suggests that menstrual blood containing fragments of endometrium is forced upward through the fallopian tubes into the peritoneal cavity. Retrograde menstruation is not an uncommon phenomenon, and it is unknown why endometrial cells implant and grow in some women but not in others. A second theory, the vas- cular or lymphatic theory , suggests that the endometrial tissue may metastasize through the lymphatics or vascular system. Another theory, the metaplastic theory , proposes that dormant, immature cellular elements, spread over a wide area during embryonic development, persist into adult life and then differentiate into endometrial tissue. Genetic and immune factors also have been studied as contributing factors to the development of endometriosis. Endometriosis usually becomes apparent in the reproductive years when the lesions are stimulated by ovarian hormones in the same way as normal endome- trium, becoming proliferative, then secretory, and finally undergoing menstrual breakdown. Bleeding into the surrounding structures can cause pain and the develop- ment of significant pelvic adhesions. Symptoms tend to be more severe premenstrually, subsiding after cessation of menstruation. Pelvic pain is the most common pre- senting symptom; other symptoms include back pain, dyspareunia, and pain on defecation and micturition. Endometriosis is associated with infertility because of adhesions that distort the pelvic anatomy and cause impaired ovum release and transport.

The gross pathologic changes that occur in endome- triosis differ with location and duration. In the ovary, the endometrial tissue may form cysts (i.e., endome- triomas filled with old blood that resembles choco- late syrup [chocolate cysts]). 6 Rupture of these cysts can cause peritonitis and adhesions. Elsewhere in the pelvis, the tissue may take the form of small hemor- rhagic lesions that may be black, bluish, red, clear, or opaque (Fig. 40-11). Some may be surrounded by scar tissue. Endometriosis may be difficult to diagnose because its symptoms mimic those of other pelvic disorders and the severity of the symptoms does not always reflect the

FIGURE 40-11. Endometriosis. Implants of endometrium on the ovary appear as red-blue nodules. (From Mutter GL, Prat J, Schwartz DA.The female reproductive system, the peritoneum and pregnancy. In: Rubin R, Strayer DS, eds. Rubin’s Pathology: Clinicopathologic Foundations of Medicine. 6th ed. Philadelphia, PA: Wolters Kluwer Health | Lippincott Williams & Wilkins; 2012:903.)