A serial section study of visually normal pelvic peritoneum in patients with endometriosis

When you see nothing at all: Outcomes following a negative laparoscopy. A systematic review

BACKGROUND

Persistent pelvic pain (PPP) is a complex and often debilitating condition. While widely accepted to be multifactorial in nature, the precise aetiology of PPP remains elusive. In many cases, women who undergo laparoscopy for PPP will have no visible pathology identified (a 'negative' laparoscopy). Currently, there are no consensus guidelines which outline the recommended management following a negative laparoscopy, and the woman's experiences and outcomes are not widely known.

AIMS

This review aims to identify and summarise the literature surrounding the experiences of women with PPP who have a negative laparoscopy; specifically, their outcomes of pain, quality of life (QoL), satisfaction with care, and their overall management.

MATERIALS AND METHODS

A systematic search of the electronic databases Ovid Medline, PubMed and Embase was performed. Studies in English exploring the outcomes of women with PPP following a negative laparoscopy were included.

RESULTS

Four studies consisting of a total of 200 women were included. Results were inconsistent. Three studies concluded that the majority of women with PPP had persistent pain following a negative laparoscopy. A single study found that pain significantly improved after negative laparoscopy. QoL outcomes varied, with two studies reporting a positive impact and two studies reporting a deleterious impact on QoL following a negative laparoscopy.

CONCLUSIONS

The impact on pain outcomes and QoL following a laparoscopy that does not diagnose pathology remains unknown, and the available evidence is insufficient to guide evidence-based practice. This review highlights a significant gap in our understanding of surgical management for PPP.

SonoPODography: A new diagnostic technique for visualizing superficial endometriosis

OBJECTIVE

To perform a pilot diagnostic accuracy study of a novel transvaginal ultrasonography procedure called saline-infusion sonoPODography to predict superficial endometriosis in patients with suspected endometriosis.

STUDY DESIGN

A prospective single-center diagnostic accuracy study was performed from September 2019-November 2019. The index test sonoPODography was performed and the results were documented in a standardized fashion. SonoPODography was performed by installing saline into the pouch of Douglas (POD) via an intrauterine balloon catheter to create an acoustic window between the ultrasound probe and surrounding structures. The pelvis was then assessed for the presence or absence of superficial endometriosis using pre-defined features. Direct visualization at laparoscopy and histological assessment of excised endometriosis confirmed the outcome. The diagnostic performance of sonoPODography was evaluated.

RESULTS

42 consecutive participants underwent sonoPODography. Superficial endometriosis was identified by sonoPODography in 24/42 (57.1 %) and in 37/42 (88.1 %) participants by direct visualization at laparoscopy. The overall diagnostic performance of sonoPODography was: accuracy 69.1 %, sensitivity 64.9 %, specificity 100.0 %, positive predictive value 100.0 %, negative predictive value 27.8 %. Amongst those without deep endometriosis/endometriomas/pouch of Douglas obliteration, the diagnostic performance was: accuracy 80.0 %, sensitivity 77.7 %, specificity 100.0 %, positive predictive value 100.0 %, negative predictive value 33.3 %. The pouch of Douglas peritoneum was the most common site of superficial endometriosis.

CONCLUSIONS

SonoPODography is a novel ultrasound-based procedure that permits the direct visualization of superficial with respectable diagnostic accuracy. The findings of this pilot study are promising and justify the initiation of a larger outpatient study. SonoPODography may establish new avenues for the non-invasive diagnosis and investigation of endometriosis.

Prevalence of occult microscopic endometriosis in clinically negative peritoneum during laparoscopy for chronic pelvic pain

OBJECTIVE

 To determine the prevalence of occult microscopic endometriosis in patients with chronic pelvic pain and negative laparoscopy.

METHODS

A retrospective cross-sectional study included women who underwent laparoscopic evaluation for chronic pelvic pain by three fellowship-trained gynecologic surgeons at a community hospital from January 2011 to December 2016. The aim was to evaluate the prevalence of microscopic endometriosis in this population.

RESULTS

 In 142 patients with clinically negative peritoneum on laparoscopy, 39% had occult microscopic endometriosis. Cramping pain score during menses was found to be lower in the positive biopsy group (6.9 vs 8.0, P=0.046). No differences were appreciated in age of menarche, pain during various parts of the menstrual cycle, or duration of symptoms. The biopsy-positive group had a younger age at time of evaluation, although not statistically significant (P=0.179). Current use of hormones affected neither biopsy results nor menstrual or pain characteristics. Detection was similar between robotic and laparoscopic cases and operative morbidity was minimal.

CONCLUSION

Occult microscopic endometriosis may be present in approximately 39% of patients with clinically negative appearing peritoneum undergoing laparoscopy for chronic pelvic pain. Given this, biopsies should be performed in patients undergoing laparoscopy who do not have visible lesions.

Occult microscopic endometriosis: undetectable by laparoscopy in normal peritoneum

STUDY QUESTION

Is there any occurrence of hidden (occult) endometriotic lesions in normal peritoneum of women with and without visible endometriosis?

SUMMARY ANSWER

We detected a slightly higher occurrence of occult microscopic endometriosis (OME) in normal peritoneum of women with visible endometriosis than in control women.

WHAT IS KNOWN ALREADY

Based on a small number of cases, the concept of invisible microscopic endometriosis in visually normal peritoneum has been reported for more than a decade but there is controversy regarding their tissue activity and clinical significance.

STUDY DESIGN, SIZE, DURATION

This case-controlled research study was conducted with prospectively collected normal peritoneal samples from 151 women with and 62 women without visible endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Normal peritoneal biopsy specimens from different pelvic sites of were collected during laparoscopy. A histological search of all peritoneal biopsy specimens for the detection of invisible endometriosis was done by immunoreaction to Ber-EP4 (epithelial cell marker), CD10 (stromal cell marker) and Calretinin (mesothelial cell marker). Tissue expression of estrogen/progesterone receptors (ER/PR) and cell proliferation marker, Ki-67, was performed by immunohistochemistry to identify tissue activity.

MAIN RESULTS AND THE ROLE OF CHANCE

Three different patterns of OME were detected based on (I) the presence of typical gland/stroma, (II) reactive hyperplastic change of endometrioid epithelial cells with surrounding stroma and (III) single-layered epithelium-lined cystic lesions with surrounding stroma. A higher tendency toward the occurrence of OME was found in women with visible endometriosis (15.2%, 23/151) compared with control women (6.4%, 4/62) (P = 0.06, χ(2) test). The epithelial cells and/or stromal cells of OME lesions were immunoreactive to Ber-EP4 and CD10 but not reactive to Calretinin. ER and PR expression was observed in all patterns of OME lesions. Ki-67 index was significantly higher in pattern I/II OME lesions than in pattern III OME lesions (P< 0.05 for each).

LIMITATIONS, REASONS FOR CAUTION

Bias in the incidence rate of OME lesions in this study cannot be ignored, because we could not analyze biopsy specimens from the Pouch of Douglas of women with revised classification of the American Society of Reproductive Medicine Stage III-IV endometriosis due to the presence of adhesions in the pelvis.

WIDER IMPLICATIONS OF THE FINDINGS

We re-confirmed a decade long old concept of invisible (occult) endometriosis in visually normal peritoneum of women with visible endometriosis. The existence of a variable amount of tissue activity in these occult lesions may contribute to the recurrence/occurrence of endometriosis or persistence/recurrence of pain manifestation in women even after successful ablation or excision of visible lesions by laparoscopy.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported in part by Grants-in-aid for Scientific Research from the Japan Society for the Promotion of Science. There is no conflict of interest related to this study.

TRIAL REGISTRATION NUMBER

Not applicable.

Endometriosis in adolescence

Endometriosis is a common cause of pelvic pain and infertility. The majority of women report symptoms since adolescence, and there are rare cases of endometriosis in premenarchal age patients. Symptoms in adolescence are similar to those in adulthood. Treatment usually consists of oral contraceptives and nonsteroidal anti-inflammatory drugs. In cases where this treatment is not successful, laparoscopy and biopsy of the lesions are necessary for diagnosis. However, emerging new technologies provide new options, in particular the use of serological markers.

Options for hormone therapy in women who have had a hysterectomy

OBJECTIVE

To review postmenopausal hormone therapy for women who have undergone hysterectomy with or without bilateral oophorectomy and to make clinical recommendations regarding changes in regimens compared with those for women with their uterus in place.

DESIGN

We conducted a literature review, including a review of current guidelines.

RESULTS

When the uterus is absent, estrogen treatment is all that is needed when hot flashes and/or genital atrophic symptoms are associated with surgical or natural menopause. Reasons to add a progestogen to an estrogen-only therapy regimen after hysterectomy include the need to reduce the risk for unopposed estrogen-dependent conditions, chief among which are endometriosis or endometrial neoplasia. Multiple lines of evidence suggest that regimens containing both estrogen and progestogen versus estrogen alone are associated with a greater relative risk of breast cancer without additional improvement in relief of hot flashes or vaginal symptoms. When a bilateral oophorectomy is performed before natural menopause, the onset of menopausal symptoms, primarily vasomotor symptoms, genital tract atrophy, and/or a decline in sexual function, is rapid, and the symptoms are more severe. Thus, the need for a decision on the use of hormone therapy is accelerated.

CONCLUSIONS

The decision to use or not use menopausal hormone therapy in women without a uterus should involve an individualized risk/benefit analysis just as it should when the uterus is present. After hysterectomy, for most patients, current literature results favor not including a progestogen. Data suggest an attenuation of the potential cardiovascular benefit of estrogen therapy in this situation, yet no better protection against bone fractures and an increase in the risk for breast cancer when both estrogen and progestogen are used.

Histopathologic findings on uterosacral ligaments in women with chronic pelvic pain and visually normal pelvis at laparoscopy

STUDY OBJECTIVE

To determine the prevalence and type of microscopic findings on laparoscopically resected uterosacral ligaments in women with chronic pelvic pain and no visible pelvic disease. The effect of this procedure on the patients' level of pain also was assessed as a secondary objective.

DESIGN

Prospective follow-up (Canadian Task Force classification II-2).

SETTING

University-affiliated hospital.

PATIENTS

Twenty-seven premenopausal women undergoing diagnostic laparoscopy for chronic pelvic pain had a normal pelvis on visual inspection. All patients underwent resection and histologic evaluation of the uterosacral ligaments. Pain relief was evaluated by use of a questionnaire administered before and at 3, 6, and 12 months after surgery.

MEASUREMENTS AND MAIN RESULTS

Microscopic examination identified endometriosis in 2 (7.4%), endosalpingiosis in 3 (11.1%), and inflammation in 14 (51.9%) patients. Laparoscopic uterosacral ligament resection was associated with a reduction in dysmenorrhea (p < or = .001), with 14 (52%) patients reporting improved or resolved symptoms. There was a statistically significant decrease in dyspareunia (p < or = .01) and in the severity of noncyclical pain (p < or = .002). Thirty-five percent of patients no longer required medication for pain control (p < or = .005). The number of days needed off work also decreased.

CONCLUSION

Despite normal laparoscopic appearance, microscopic endometriosis, endosalpingiosis, and inflammatory changes were found in uterosacral ligaments in 17 (63%) women with chronic pelvic pain. Laparoscopic resection of uterosacral ligaments improved dysmenorrhea, dyspareunia, and noncyclical pain and decreased the number of days lost from work, as well as the proportion of patients who required medication for pain control.

Interobserver variability in the diagnosis of minimal and mild endometriosis

STUDY OBJECTIVE

To evaluate the observer's influence on the diagnosis and classification of endometriosis according to the rASRM classification.

DESIGN

: Prospective analysis.

SETTING

University hospital.

PATIENTS

Digital videotapes of laparoscopies in three patients with typical endometriotic disorders (rASRM I, II and no endometriosis).

INTERVENTION

One hundred and eight gynecologic surgeons were asked to indicate the endometriotic lesions on a prepared surgical sketch and to classify the site according to the rASRM classification.

MEASUREMENTS AND MAIN RESULTS

Total number, location and morphology of endometriotic lesions, rASRM classification. The interobserver correlation concerning the number of lesions ranged between 18% (rASRM II) and 30%. (rASRM I). There was marginal correlation regarding the location of endometriotic lesions. Kendall W coefficient ranged from 0.14 (rASRM II) to 0.44 (rASRM I) (p < 0.001). Only 13% (rASRM II) to 22% (rASRM I) of observers used the correct endometriotic classification. None of the participants specified the morphological characteristics of endometriotic lesions according to the rASRM classification.

CONCLUSION

Visual assessment of an operative situs with minimal and mild endometriosis is subject to a considerable interindividual variability. One and the same lesion is assessed quite differently by different observers. Histopathological verification seems to be necessary to objectify the diagnosis of endometriosis.

Detection of Nonpigmented Endometriotic Lesions with 5-Aminolevulinic Acid-Induced Fluorescence

STUDY OBJECTIVE

To evaluate the feasibility of fluorescence diagnosis of nonpigmented (red and white) endometriotic lesions with 20 mg/kg of 5-aminolevulinc acid (5-ALA) 5-7 and 10-14 hours before surgery.

DESIGN

Prospective analysis (Canadian Task Force classification II-2).

SETTING

University hospital.

PATIENTS

Twenty-four consecutive patients with suspected endometriosis undergoing laparoscopy.

INTERVENTION

Laparoscopic surgery under white light illumination and fluorescence diagnosis.

MEASUREMENTS AND MAIN RESULTS

The total number of endometriotic lesions detected under white light illumination was compared with the number of lesions detected with fluorescence diagnosis. Fluorescence diagnosis yielded an overall improvement of 35% in the detection of nonpigmented endometriotic lesions compared with white light illumination. Sensitivity (91%) and specificity (79%) were similar 5-7 and 10-14 hours before surgery.

CONCLUSION

The dosage of 20 mg/kg body weight of 5-ALA is feasible for fluorescence diagnosis of nonpigmented endometriosis. Sensitivity of fluorescence diagnosis with 20 mg/kg is similar to that achieved with a 30-mg/kg dose. Sensitivity does not change within the application period 5-7 and 10-14 hours before surgery.

Laparoscopic Spectral Analysis of Endometriosis

STUDY OBJECTIVE

To determine if lesions of endometriosis will preferentially absorb light of the blue spectrum thus enabling the detection of nonvisualized disease.

DESIGN

Retrospective analysis (Canadian Task Force classification II-2).

SETTING

University based teaching hospital.

PATIENTS

Twenty-five women with pain suggestive of endometriosis.

INTERVENTION

A noninvasive technique was employed to better visualize lesions of endometriosis at time of diagnostic laparoscopy.

MEASUREMENTS AND MAIN RESULTS

A Storz PDD light source, which delivers a blue light at a specified frequency of 440 Hz, was used concurrently with full-spectrum white light. A Storz PDD laparoscope, which utilizes filters to detect the blue spectrum of light, was then coupled to the blue-light source. Lesions of endometriosis were compared using standard white light to that of blue light. The new lesions seen using blue light were sampled to confirm pathology. Using standard white light, black, red, and clear lesions were identified, and the borders of the lesions were marked. The same lesions were observed using the blue spectrum of light. The lesions absorbed blue light, but nonvisible endometriosis surrounding the classic lesions were also identified. Biopsies confirmed endometriosis in newly visible lesions.

CONCLUSION

Lesions of endometriosis preferentially absorb the blue-light spectrum. Laparoscopic spectral analysis enables visualization of previously nonvisible endometriosis and makes other visible lesions easier to identify.

Scanning electron microscopy of endometriotic lesions in the pelvic peritoneum and the histogenesis of endometriosis

OBJECTIVE

To determine whether the epithelium of an endometriotic lesion has eutopic endometrial glandular epithelium morphology or not for the histogenesis of endometriosis.

METHOD

Scanning electron microscopy (SEM) of the endometrium was done for 25 cases. Histologically proven endometriotic lesions of 10 of these 25 cases were processed for SEM. Peroneum samples of another 15 cases without histological endometriosis were also studied.

RESULT

Three of 10 cases with histologically proven endometriotic lesions revealed endometrium-like morphology by SEM, whereas normal appearing peritoneum without histological endometriosis in 15 cases showed no endometrium-like structures by SEM.

CONCLUSION

Although abovementioned results did not support retrograde menstruation and implantation, they suggested a possibility of derivation from the endometrium.

Adolescent endometriosis: diagnosis and treatment approaches

OBJECTIVES

To review the etiologies, diagnosis, and treatment options of adolescent endometriosis.

METHODS

Review of publications relating to adolescent endometriosis.

RESULTS

Endometriosis occurs in adolescents as young as 8 years of age; furthermore, there have been documented cases of endometriosis occurring prior to menarche. Adolescents presenting with pelvic pain are treated with cyclic combination oral contraceptive pills and nonsteroidal anti-inflammatory agents. If the pain does not respond to these therapies, then in adolescents as in adults, an operative laparoscopy is recommended for the diagnosis and surgical management of endometriosis. The operating gynecologist should be familiar with the appearance of the complete spectrum of various morphologies of endometriosis, as adolescents tend to have clear, red, white, and/or yellow-brown lesions more frequently than black or blue lesions. Subtle clear lesions of endometriosis may be better visualized by filling the pelvis with irrigation fluid so that the clear lesions can be appreciated in a three-dimensional appearance. Young women who are found to have endometriosis by laparoscopy may present with acyclic, cyclic, and constant pelvic pain. Adolescents with pelvic pain not responding to conventional medical therapy have approximately a 70% prevalence of endometriosis. It is known that endometriosis is a progressive disease and since there is no cure, adolescents with endometriosis require long-term medical management until the time in their lives when they have completed childbearing. Psychosocial support is extremely important for this population of young women with endometriosis.

CONCLUSIONS

Endometriosis occurs in adolescents, and presenting symptoms may vary from those seen in adult women with the disease. All health care providers must be aware of the existence of adolescent endometriosis. They should also be aware of the presenting symptoms so that the adolescent can be appropriately referred to a gynecologist comfortable with medical and surgical treatment options in this patient population. If laparoscopy is to be undertaken, the gynecologist must be prepared not only to diagnose but to surgically manage endometriosis. In addition, the subtle laparoscopic findings of endometriosis in adolescents must be recognized for an appropriate diagnosis. Long-term medical therapy will hopefully decrease pain and the progression of the disease, thus decreasing the risk of advanced-stage disease and infertility.

Intravesicular pain mapping

The lack of success with the physician-only approach to bladder pain and interstitial cystitis demonstrates the need for a fresh new method. Such an approach, in which the patient becomes an integral part of the operating team, verifying that the operative findings are the source of the pain and that treatment of these areas will lead to the resolution of the pain, needs to be examined further.

Adolescent endometriosis

PURPOSE OF REVIEW

Endometriosis can exist in the adolescent female. It can be a very disruptive disease and cause significant dysfunction at a time in life when self-esteem, school attendance, and school performance are critical to achievement of life goals. Approaches to diagnosis and management in the recent literature are reviewed, focusing on those that apply directly to the adolescent or indirectly, by extrapolation from work done in the adult population. Practical strategies for adolescent patient care are presented.

RECENT FINDINGS

Recent research has focused on the efficacy of current treatment modalities and management of potential adverse side effects. Possible etiologies of endometriosis have been proposed, and therapies directed at those causes are being explored. Methods of diagnosis, both invasive and noninvasive, have been studied in order to determine the most effective way of diagnosing the disease.

SUMMARY

A better understanding of the etiology of endometriosis would probably assist in determining the most suitable treatment strategies. Future work in adolescent endometriosis should focus on developing safe, minimally invasive, yet definitive options for diagnosis and treatment.

Was Sampson wrong?

OBJECTIVE

Sampson's theory of reflux menstruation suggests that endometriosis is one form of a condition known as an autotransplant. This study seeks to characterize autotransplants as they are described in the literature and to determine whether endometriosis resembles an autotransplant.

DESIGN

Literature review of published studies containing the following types of information: [1] characterization of the histologic features, immunohistochemistry, or structural function of autotransplants; and [2] comparisons of endometriosis with endometrium.

MAIN OUTCOME MEASURE(S)

Characteristics of multiple types of autotransplants were noted. Similarity or dissimilarity of endometriosis and endometrium was tabulated to judge qualitatively whether the bulk of the evidence supports the notion that endometriosis is an autotransplant.

RESULT(S)

Autotransplants remain very similar or identical to eutopic tissues of origin, regardless of the length of time following autotransplantation. Endometriosis differs in many profound and fundamental ways from eutopic endometrium, including clonality of origin, enzymatic activity, protein expression, and histologic and morphologic characteristics. A minority of studies has found similarities between endometriosis and eutopic endometrium.

CONCLUSION(S)

Endometriosis is dissimilar to eutopic endometrium and therefore lacks characteristics of an autotransplant. Sampson's theory of origin of endometriosis is not supported by the results of this study. Studies of experimental endometriosis that have not used menstrual endometrium may be misleading.

Research aspects of endometriosis surgery

This paper asks various questions regarding endometriosis surgery. These address the research issues of the necessity of treatment, surgical technique, terminology, the definition of the rectovaginal septum, standards for research, and the impact of RBRVS/RDG.

Endometriosis: correlation between histologic and visual findings at laparoscopy

OBJECTIVE

The purpose of this study was to correlate the diagnosis of endometriosis on the basis of visualization at laparoscopy with the pathologic diagnosis.

STUDY DESIGN

A prospective study of 44 patients undergoing laparoscopy for the evaluation of chronic pelvic pain was carried out. All areas suggestive of endometriosis were excised and examined pathologically. Peritoneal biopsy specimens were obtained from areas of normal-appearing peritoneum to rule out microscopic endometriosis. All lesions were identified by anatomic site. Visual and histologic American Fertility Society scores were compared. The positive predictive value, sensitivity, negative predictive value, and specificity were determined for visually identified endometriosis versus the histologic correlate.

RESULTS

The mean prevalence of abnormalities visually consistent with endometriosis was 36%, with 18% confirmed histologically. The positive predictive value was 45%; sensitivity, 97%; negative predictive value, 99%; and specificity, 77%; for visual versus histologic diagnosis of endometriosis. Thirty-six percent of the diagnoses were downstaged on the basis of histologic findings.

CONCLUSION

A diagnosis of endometriosis should be established only after histologic confirmation.

Mapping the source and character of pain due to endometriosis by patient-assisted laparoscopy

STUDY OBJECTIVE

To determine by patient-assisted laparoscopy (PAL) the relationship of lesions of endometriosis to pelvic pain.

DESIGN

Prospective non-randomized study (Canadian Task Force classification II-1).

SETTING

University based facility.

PATIENTS

Fifty women with endometriosis.

INTERVENTION

Lesions of endometriosis were examined as to color and size, and these areas were mapped for pain.

MEASUREMENTS AND MAIN RESULTS

Lesions in all categories of colors and shapes were palpated. In lesions that did provoke a pain response, red and vascular lesions were most painful, followed by clear and white scar lesions. Least painful were black lesions. Pain extended beyond lesions to normal-looking peritoneum for up to 27 mm, but was not consistent with respect to type of lesion.

CONCLUSION

Pain of endometriosis has little relationship to location or color of lesions. It can extend beyond visible lesions to normal peritoneum. Input from patients by PAL may be essential to achieve successful therapy and eliminate excessive surgery and risk.

Reproductive disorders associated with pelvic pain

Pelvic pain is common in adolescents and can result from a number of physiological and pathological etiologies, both gynecologic and nongynecologic in origin. The evaluation, diagnosis, and management of these conditions involve both medical and surgical approaches. In this review, the authors present a comprehensive approach to the care of adolescents with pelvic pain associated with dysmenorrhea, endometriosis, and obstruction of the genital tract.

Prevalence of endometriosis in adolescent girls with chronic pelvic pain not responding to conventional therapy

STUDY OBJECTIVE

To evaluate adolescent girls with chronic pelvic pain not responding to conventional medical therapy, using advances in operative laparoscopy to determine endometriosis prevalence, clinical stage, and type of lesion.

DESIGN

A descriptive retrospective study of subjects who (1) were referred for the evaluation of chronic pelvic pain, (2) did not respond to a nonsteroidal anti-inflammatory drug and an oral contraceptive pill, and (3) underwent a laparoscopy to determine the etiology of the pelvic pain.

SETTING

Patients referred to a surgical gynecologist in a pediatric/adolescent gynecology and reproductive endocrine academic practice.

PARTICIPANTS

All patients younger than 22 years of age with chronic pelvic pain.

INTERVENTION

Operative laparoscopy to determine the etiology of the chronic pelvic pain.

MAIN OUTCOME MEASURES

Operative laparoscopy results including stage and description of endometriosis.

RESULTS

More than two thirds of the study population (69.6%) was found to have endometriosis. All subjects had either stage I or II as determined by the American Fertility Society's classification system. The nature of the pain in the 32 subjects with endometriosis was both acyclic and cyclic in 20 (62.5%), acyclic only in 9 (28.1%), and cyclic only in 3 (9.4%). Other presenting symptoms included gastrointestinal in 11 (34.3%), urinary in 4 (12.5%), and irregular menses in 3 (9.4%).

CONCLUSIONS

Adolescents with chronic pelvic pain not responding to medical therapy have a high rate of endometriosis and should be referred to a gynecologist who is experienced with the subtle laparoscopic findings of atypical endometriosis to diagnose the etiology of the pelvic pain and initiate appropriate therapy.

Clinical relevance of the baboon as a model for the study of endometriosis

OBJECTIVE

To review the value of the baboon as a model for the study of endometriosis.

DATA IDENTIFICATION AND SELECTION

Studies performed at the Institute of Primate Research in Nairobi, Kenya (1990-1994), and published in peer-reviewed journals.

RESULT(S)

Spontaneous endometriosis was found in about 25% of the baboons, and its prevalence increased with the duration of captivity. The laparoscopic appearance, pelvic localization, and microscopic aspects of the disease were similar to endometriosis in women. Microscopic endometriosis in macroscopically normal peritoneum was rare. Sampson's hypothesis (i.e., retrograde menstruation causes endometriosis) was supported by the increased incidence of retrograde menstruation in baboons with spontaneous endometriosis, the observation that cervical occlusion could cause retrograde menstruation and endometriosis, and the finding that intrapelvic injection of menstrual endometrium caused experimental moderate to severe endometriosis similar to the spontaneous disease. During follow-up of more than 2 years, endometriosis in baboons appeared to be a progressive disease, with active remodeling between several types of lesions. Progression was stimulated by high-dose immunosuppression. Fertility was normal in baboons with minimal disease but was reduced in baboons with mild, moderate, or severe endometriosis, possibly related to an increased incidence and recurrence of the luteinized unruptured follicle syndrome.

CONCLUSION(S)

The baboon is a good model for the study of endometriosis.

A serial section study of visually normal posterior pelvic peritoneum from baboons (Papio cynocephalus, Papio anubis) with and without spontaneous minimal endometriosis

OBJECTIVES

To determine if microscopic endometriosis exists in visually normal pelvic peritoneum from baboons with and without endometriosis.

DESIGN

Observational histologic study at Institute of Primate Research, Nairobi, Kenya.

SUBJECTS

Seventeen baboons including 13 adult females (5 with histologically proven endometriosis, 8 with a normal pelvis) and 4 juveniles (1 female and 3 males).

INTERVENTIONS

Diagnostic laparoscopy with identification of visually normal pelvic peritoneum before euthanasia, followed by laparotomy with excision of a large area (at least 4 x 6 cm or 24 cm2 per animal, 408 cm2 surface in all baboons) of this visually normal-appearing peritoneum.

MAIN OUTCOME MEASURE

Presence of microscopic endometriosis (endometrial glands and stroma) in serial sections of visually normal pelvic peritoneum.

RESULTS

Two adjacent glandular structures compatible with endometriosis were found in normal peritoneum obtained during menses from one female baboon without macroscopic disease. Microscopic endometriosis was not detected in the other female primates with or without macroscopic disease or in male animals.

CONCLUSION

Microscopic endometriosis was found in only 1 of 14 female baboons (prevalence 7%; 95% confidence interval 0% to 33%) with visually normal pelvic peritoneum. These findings suggest that, with the paucity of human data available, more studies are needed before concluding that massive microscopic disease exists in visually normal-appearing peritoneum of women.