Contents
Introduction
Endometrial polyps are benign tumours of the endometrium that tend to develop between 40 and 50 years of age and are also quite common after the menopause. They can present with
abnormal uterine bleeding; less commonly attempts by the uterus to expel the polyp can cause
dysmenorrhoea.
Endometrial polyps are most common in the fundus and can have a narrow or broad attachment to the underlying endometrium. The range in size is considerable.
The majority of polyps are overgrowths of the endometrium and contain glands and stroma. Smooth muscle may be present in the stroma. There tend to be thick walled blood vessels in the base of the polyp.
Some polyps have the features of endometrial hyperplasia. Other polyps have an atrophic pattern.
Polyps may develop in association with tamoxifen use.
The diagnosis may be made either via endometrial curetttings of hysteroscopic excision.
Atypical Polypoid Adenomyoma
The atypical polypoid adenomyoma occurs in the reproductive years. It macroscopically resembles an endometrial polyp. However, the lesion is composed of irregular glands which are arranged in a disorderly fashion between bundles of smooth muscle. The co-existing feature of cytological atypia in the glands can cause confusion with adenocarcinoma if the polypoid nature of the lesion is neither communicated nor appreciated.
Leiomyosarcoma
Leiomyosarcomas account for around 1.3% of uterine malignancies. The average age of onset is 52 years.
The majority of leiomyosarcomas are solitary (although this does not preclude the presence of leiomyomas in the same uterus, especially given the common nature of fibroids). Leiomyosarcomas are poorly defined masses that are soft and fleshy. They are grey-pink and their cut surfaces show haemorrhage and/or necrosis. Their size usually exceeds 50mm.
The tumours are composed of cytologically atypical smooth muscle cells which invade the adjacent myometrium. Zones of necrosis that are clearly demarcated from the surrounding tumour are an important diagnostic feature, as is increased mitotic activity (at least 10 mitoses per high power field) and hypercellularity.
Metastatic sites include the lung, brain and bone. As is not unusual for sarcomas, uterine leiomyosarcomas are not particularly interested in metastasising to lymph nodes.
The overall five year survivial is 40%. However, the long term survival if the tumour has spread beyond the uterus is very low.
Endometrial Stromal Tumour
The nomenclature of endometrial stromal tumours has been in a state of flux in recent years, partly because one of the key distinguishing features between an endometrial stromal nodule and a low grade endometrial stromal sarcoma is the circumscription of the tumour relative to the adjacent tissue, a factor which cannot be assessed in a curettage sample.
The endometrial stromal nodule is a rare lesion that can affect a wide age range, although occurs in premenopausal women in 75% of cases. The average size is 40mm. The tumour is rounded and clearly defined relative to the adjacent tissue; it may bulge into the myometrium. The tumour is composed of cells that resemble those of proliferative phase endometrium. Only minimal cytological atypia is encountered.
The low grade endometrial stromal sarcoma comprises only 10% of uterine sarcomas and is a rare neoplasm. The constituent cells are very similar to those of an endometrial stromal nodule but they invade the adjacent myometrium and the tumour lacks the circumscription of an endometrial stromal nodule; these features may not be assessable in endometrial curettings and a more generic term such as endometrial stromal tumour may need to be used in the report to indicate that both possibilities still pertain. The vascularity may be different from that of the endometrial stromal nodule.
The high grade endometrial stroma sarcoma no longer exists under that name and has become a high grade uterine sarcoma. This shift in nomenclature reflects the difficulty in determing the cell of origin of a high grade sarcoma of the uterus and that the absence of evidence of endometrial stromal differentiation does not exclude the possibility.
Clinical Features
Despite the different nature of the tumours described above their repertoire of clinical features is limited. Lesions in the uterus tend to come to attention by causing a
disorder of menstruation and tumours will lean towards menorrhagia, intermenstrual bleeding or postmenopausal bleeding.
Malignant tumours may be associated with non-specific features of malignancy that do not permit localisation of the tumour, or even a definite diagnosis of malignancy.