Myometrium: Non—Neoplastic Conditions and Miscellaneous Neoplasms

Abstract

This is a disease principally of parous women in the later years of their reproductive life, and is characterized by the presence of endometrial tissue deep within the myometrium (Figure 17.1): there is almost invariably an associated hypertrophy of smooth muscle fibres around the islands of ectopic endometrium. When considering this condition it has always to be borne in mind that the interface between the normal endometrium and the myometrium is often very irregular, and that tangential cutting of the basal endometrium may produce apparently isolated islands of endometrial tissue surrounded by myometrium. It is for this reason that the word 'deep' is insisted upon in the definition of adenomyosis though there has been considerable dispute as to its interpretation. Very often it has been suggested that to justify a diagnosis of adenomyosis the ectopic endometrium should be one high power microscopic field, or a proportion of a low power microscopic field, below the base of the endometrium; but these are poorly defined criteria which take no account of variations in myometrial thickness, and the defining criterion that the intramyometrial glands must be at a distance of more than one quarter of the full thickness of the uterine wall below the endometrial—myometrial junction is to be preferred.