Diagnosing endometrial hyperplasia: why is it so difficult to agree?

Endometrial polyps and the risk of atypical hyperplasia on biopsies of unremarkable endometrium: a study on 694 patients with benign endometrial polyps

The objective of our study was to examine the relationship between benign endometrial polyps and the underlying endometrium, analyzing factors associated with endometrial hyperplasia with and without atypia. Six hundred and ninety-four consecutive patients with benign endometrial polyps underwent hysteroscopic removal of the polyps combined with 2 biopsies of unremarkable endometrium. Hysteroscopic removal of endometrial polyps with 2 endometrial biopsies far from the base of the polyp were performed. The weight of each polyp was determined. Multivariable logistic regression analysis was used examining factors potentially associated with endometrial hyperplasia with and without atypia on endometrial biopsies. Overall, 18% of women had hyperplasia without atypia and 7.3% had atypia (with simple/complex hyperplasia) on hysteroscopically unremarkable endometrium. In postmenopause, 21.6% had hyperplasia without atypia, 12% atypia, and 1.2% adenocarcinoma on the sampled endometrium. At multivariable analysis, postmenopausal women with larger polyps had a 3.6-fold higher likelihood of atypia (odds ratio=3.6; 95% confidence interval: 1.3-10.3); in premenopause the likelihood of atypia was significantly associated with polyp weight and age above 40 years. Our findings suggest that important endometrial lesions are not always evident by hysteroscopic visualization. Therefore, endometrial biopsies should not be limited only to hysteroscopically evident lesions. Polypectomy should be combined with a histopathologic evaluation of the background endometrium, particularly in women with higher-risk characteristics.

Strategies in the histologic diagnosis of low-grade glandular endometrial neoplasm

PURPOSE OF REVIEW

Histological diagnosis of well differentiated endometrioid adenocarcinoma (WDA) has been challenging over the years. Considering the impact of this diagnosis on treatment and follow-up of the patient, in this review, we have discussed and evaluated the most useful of the proposed histological criteria for diagnosis of WDA and its distinction from mimic lesions.

RECENT FINDINGS

Diagnostic criteria for WDA are proposed regarding histologic features predicting the presence of myometrial or endometrial stromal invasion by proliferating glands, or aggressive behavior.

SUMMARY

Most useful diagnostic histological features in WDA, such as cribriform, labyrinthine, and confluent glandular patterns, and stromal desmoplasia are highlighted. Presence of these features differentiates WDA from mimics and justifies aggressive treatment.

Complex atypical endometrial hyperplasia: the risk of unrecognized adenocarcinoma and value of preoperative dilation and curettage

OBJECTIVE

To evaluate whether preoperative dilation and curettage (D&C) lowers the risk of unexpected cancer at hysterectomy.

METHODS

Women with complex atypical endometrial hyperplasia on sampling from January 2000 to May 2008 who underwent hysterectomy within 6 months were identified using a pathology database. Patient age, sampling procedures, and hysterectomy pathology were recorded. Women were categorized as having either an office biopsy-based evaluation or a curettage-based evaluation. The proportion of women with cancer at surgery was estimated and compared for the two groups.

RESULTS

Of 824 women with complex atypical endometrial hyperplasia on initial sampling, 48% were found to have cancer. For 100 women, cancer was diagnosed preoperatively by additional sampling before hysterectomy. For the remaining 724, 298 (41%) had unexpected cancer at hysterectomy. The diagnosis of complex atypical endometrial hyperplasia was biopsy-based for 531 (73%) and curettage-based for 193 (27%). The risk of cancer for women who had a D&C was significantly lower than for those who had biopsy, but still of concern (30% compared with 45%, P<.001), as was the risk of myometrial invasion (18% compared with 25%, P=.05). Age was strongly correlated to risk of cancer, invasive cancer, and deeply invasive or grade 3 disease.

CONCLUSION

Dilation and curettage lowered the risk of unexpected cancer compared with biopsy, but 18% of women still had invasive cancer found at hysterectomy. The risk of unexpected cancer is strongly related to age. Dilation and curettage can help detect cancer preoperatively but is not reliable for excluding cancer.

LEVEL OF EVIDENCE

II.

Incidence of endometrial hyperplasia

OBJECTIVE

The objective of the study was to estimate the age-specific incidence of endometrial hyperplasia: simple, complex, and atypical, in order of increasing likelihood of progression to carcinoma.

STUDY DESIGN

Women aged 18-90 years with endometrial pathology specimens (1985-2003) at a large integrated health plan were identified using automated data. Incidence rates were obtained by dividing the number of cases by the estimated number of female health plan enrollees who retained a uterus.

RESULTS

Endometrial hyperplasia peak incidence was: simple, 142 per 100,000 woman-years, complex, 213 per 100,000 woman-years, both in the early 50s; and atypical, 56 per 100,000 woman-years in the early 60s. Age-adjusted incidence decreased over the study period, especially for atypical hyperplasia.

CONCLUSION

Endometrial hyperplasia incidence without and with atypia peaks in the early postmenopausal years and in the early 60s, respectively. Given that some cases of endometrial hyperplasia likely go undiagnosed, the figures provided should be viewed as minimum estimates of the true incidence.

Progestin therapy of complex endometrial hyperplasia with and without atypia

OBJECTIVE

To assess the likelihood of histologic persistence/progression of complex hyperplasia and atypical hyperplasia among women treated with progestin compared with those not treated, with attention to type, dose, and duration.

METHODS

This was a cohort study at an integrated health plan of women, ages 18-85 years, with complex or atypical hyperplasia on independent pathology review with a second endometrial specimen in the 2-6 months after the index diagnosis. Progestin therapy between index diagnosis and follow-up biopsy was determined from the pharmacy database. Medical record abstraction was performed. Relative risks (RRs), adjusted for age and body mass index, were calculated.

RESULTS

Among 185 women, average age 55.9 years, follow-up 16.1 weeks, 115 had complex and 70 had atypical hyperplasia. Among women with complex hyperplasia, 28.4% of those treated with progestin and 30.0% of those not treated had persistence/progression (RR 1.20, 95% confidence interval [CI] 0.53-2.72). Among women with atypical hyperplasia, 26.9% of those treated with progestin and 66.7% of those not treated had persistence/progression (RR 0.39, 95% CI 0.21-0.70); there was a suggestion that use of at least a medium dose, or a duration of at least 3 months, was associated with a particularly low probability of persistence/progression.

CONCLUSION

Although progestin treatment of women with atypical hyperplasia was associated with a substantial increase in the likelihood of regression of the lesion during the ensuing 2-6 months, persistence/progression was nonetheless present in more than one quarter of treated women. Regression of complex hyperplasia without atypia was common whether progestin had or had not been used.

Low-grade endometrial adenocarcinoma: a diagnostic algorithm for distinguishing atypical endometrial hyperplasia and other benign (and malignant) mimics

The distinction between endometrial hyperplasia and well-differentiated adenocarcinoma of the endometrium continues to be a difficult differential diagnosis in surgical pathology. Evidence-based diagnostic criteria for well-differentiated endometrial adenocarcinoma focus on histologic features that predict myoinvasion in the hysterectomy specimen. Only 2 diagnostic criteria with significant power aid in this distinction: complex glandular architectural patterns (glandular confluence, intraglandular complexity, and hierarchical papillary architecture) and marked cytologic atypia beyond that typically defined as atypical hyperplasia (ie, prominent macronucleoli visible at low power and marked nuclear pleomorphism). Application of these 2 criteria in problematic endometrial proliferations allows stratification of patients into 3 risk categories: very low risk (< 0.05% risk of myoinvasion at hysterectomy)=complex atypical hyperplasia; intermediate risk (5.5% risk of myoinvasion at hysterectomy)=complex atypical hyperplasia, cannot exclude well-differentiated adenocarcinoma (borderline); and high risk (20% risk of myoinvasion at hysterectomy)=well-differentiated adenocarcinoma. In order to optimize the use of these diagnostic criteria, a variety of gland forming lesions that may mimic well-differentiated endometrioid adenocarcinoma must first be excluded. In addition, unusual morphologic patterns of low-grade endometrioid adenocarcinoma should be recognized, as they may cause confusion with other, higher grade (and therefore, more clinically aggressive) endometrial processes.

Presence of endometrial adenocarcinoma in situ in complex atypical endometrial hyperplasia is associated with increased incidence of endometrial carcinoma in subsequent hysterectomy

The distinction of complex atypical endometrial hyperplasia from endometrial adenocarcinoma is often problematic. Foci of back-to-back arrangement of glands or foci of cribriform arrangement of glands smaller than 2.1 mm in diameter are considered insufficient for the diagnosis of endometrial adenocarcinoma by some authors, and sufficient to be diagnosed as endometrial adenocarcinoma by other authors. We refer to these foci as endometrial adenocarcinoma in situ. In this study, we evaluated findings in subsequent hysterectomy in complex atypical endometrial hyperplasia patients with and without adenocarcinoma in situ. Follow-up findings, including the presence or absence of endometrial adenocarcinoma in the hysterectomy specimen, the grade of the carcinoma and the depth of myometrial invasion were analyzed. Of the total 87 patients with complex atypical endometrial hyperplasia, 33 patients had adenocarcinoma in situ and 54 lacked adenocarcinoma in situ. Of 33 patients 22 (66%) with adenocarcinoma in situ had endometrial adenocarcinoma on subsequent hysterectomy vs 13 of 54 (24%) patients without adenocarcinoma in situ (P=0.0001). Myoinvasive endometrial adenocarcinoma was present in 20 of 33 (61%) patients with adenocarcinoma in situ vs 8 of the 54 (15%) patients without adenocarcinoma in situ (P< or =0.0001). The depth of myometrial invasion in cases with myoinvasion was 24.5+19.4% in patients with adenocarcinoma in situ and 12.8+8.5% in patients without adenocarcinoma in situ (P=0.05). Among patients younger than age of 50, 5 of the 7 (71%) with adenocarcinoma in situ had myoinvasive carcinoma vs 2 of the 13 (15%) without adenocarcinoma in situ (P=0.02). The likelihood of finding endometrial adenocarcinoma in subsequent hysterectomy in patients with complex atypical endometrial hyperplasia is significantly increased if adenocarcinoma in situ is present in prior endometrial sampling. Endometrial adenocarcinomas in patients with adenocarcinoma in situ are far more frequently myoinvasive, and invade to a greater depth than endometrial adenocarcinomas seen in patients without adenocarcinoma in situ. Use of adenocarcinoma in situ terminology could lead to improved management of patients with complex atypical endometrial hyperplasia.

Risk of complex and atypical endometrial hyperplasia in relation to anthropometric measures and reproductive history

The authors sought to test the hypothesis that characteristics and exposures which influence the balance of estrogen and progesterone bear on the incidence of endometrial hyperplasia (EH), a noninvasive proliferation of the lining of the uterus. Cases included all female members of Group Health (Washington State) who were diagnosed with complex EH or EH with atypia during the period 1985-2003 and whose diagnoses were confirmed in a pathology review (n = 446). Controls were selected randomly from Group Health membership files and were matched to the cases by age and enrollment status at the reference date. An increased risk of EH was associated with increasing body mass index and nulliparity. There was a suggestion of a decreased risk of EH with atypia among current smokers. No association with diabetes or hypertension was found. The risk factors observed to be associated with EH in this study are similar to those associated with endometrial cancer. Whether these risk factors predispose women to cancer simply by increasing EH incidence or continue to augment cancer risk even after EH is present is currently unknown.