Endometrial hyperplasia refers to a process in which there is a proliferation
of endometrial glands of irregular size and shape with an increase in gland/stroma
ration compared to proliferative endometrium. It is a morphological continuum
that ranges from simple glandular crowding to atypical glands with features
indistinguishable from early adenocarcinoma. Most are thought to result from
persistent, prolonged estrogenic stimulation of the endometrium. A common
cause is a succession of anovulatory cycles. It may also be caused by excessive
endogenously produced estrogen in polycystic ovary syndrome including Stein-Leventhal
syndrome, functioning granulosa cell tumors of the ovary and excessive ovarian
cortical function (cortical stromal hyperplasia) or exogenous administered
The condition most commonly occurs in perimenopausal women who then present
with abnormal bleeding.
The appearance of the endometrial cavity containing hyperplastic tissue is
variable. In many cases, the endometrium is thickened and polypoid, with abundant
tissue obtained at endometrial curettage. In others, especially postmenopausal
women, curettings are scanty.
In general, the condition is characterized by proliferation of both glands
and stroma. In spite of proliferation of both endometrial components, glandular
overcrowding occurs. Endometrial hyperplasia is histologically classified
Architecture as: simple or complex depending on the degree of glandular complexity
and crowding, and
Cytologic features as: with or without atypia.
Simple hyperplasia (cystic hyperplasia) glands are cystically
dilated and with occasional outpouching surrounded by abundant densely cellular
stroma and give a "Swiss Cheese" appearance. No cellular atypia
Simple hyperplasia with dilated glands
Complex hyperplasia glands are complex with papillary intraluminal
tufting and irregular shapes accompanied by a crowded, back-to-back arrangement
with very little intervening stroma. Cellular atypia is absent.
Simple atypical hyperplasia glands are dispersed within abundant
stroma and lined by enlarged cells with increased nuclear-cytoplasmic ratio
Complex atypical hyperplasia characterized by crowded glands
showing cellular stratification, piling of epithelium into tufts, and atypia
in the form of enlarged, pleomorphic and hyperchromatic nuclei and prominent
The process of hyperplasia may be generalized throughout the endometrial
cavity or localized to one or more areas.
Complex atypical hyperplasia with back-to-back arrangement of glands and papillary
Clinical behavior and premalignant potential
Some revert to normal spontaneously or with medical treatment, others persist
as hyperplasia, and a few progresses to endometrial adenocarcinoma. Generally,
patients with atypical hyperplasia are more likely to develop carcinoma than
those with benign endometrial lesions. The risks are:
- Complex atypical 30%
- Simple atypical 10%
- Complex 3%
- Simple 1%
Atypical hyperplasia in postmenopausal women appears to have a higher rate
of progression to adenocarcinoma.
Question: What other lesions in the female genital tract are analogous
to endometrial hyperplasia?