orm localized cystic structures having the potential for spontaneous rupture. In particular, ovarian cysts--or endometriomas--can become quite large. Their size derives from repeated bleedings. As this coagulated blood progressively accumulates it can result in massive deposits of a chocolate-like material (12:35).
In addition to pelvic endometriosis, endometriotic lesions may also occur in other anatomic regions. This "extrapelvic endometriosis" may be classified according to its location. Hence, the four major subdivisions of extrapelvic endometriosis are as follows: (1) intestinal tract endometriosis; (2) urinary tract endometriosis; (3) pulmonary and thoracic endometriosis; and (4) endometriosis of other sites. In general, lesion frequency tends to decrease with increasing distance from the uterus and fallopian tubes. Moreover, within the abdominal cavity, endometriosis of the intestinal tract occurs more frequently than endometriosis of the urinary tract. Furthermore, although virtually every organ system and tissue in the human female body is susceptible to this disease, outside of the abdominal cavity the most common site of endometriotic implantation is the thorax. The only organ which seems to exhibit a resistance to endometriotic involvement is the spleen (14:151-180).
Thirdly, one disease which is very similar to endometriosis is adenomyosis, or "internal endometriosis (8:157)." Adenomyosis involves aberrant growth of endometrial glands and stroma within the uterine wall. It differs from endometriosis in that it is not responsive to cyclic ovarian hormone production. Such abnormal cellular growth generally occurs at a depth of at least 2.5 mm from the basalis layer of the endometrium. Like endometriosis, it may give rise to either a diffuse or a localized form of disease. With diffuse adenomyosis, lesions may be scattered throughout the uterine musculature. In contrast, localized disease may give ri...