Slide 76.Adenomyosis, Uterine corpus

A. Brief Descriptions

  1. Definition: ectopic islands of endometrial tissue in the myometrium.

  2. Symptoms: menorrhagia or dysmenorrhea; general and not diagnostic.

B. Gross Findings

  1. Uterine enlargement & irregular thickening of the uterine wall, with red-brown blood pigmentation within the myometrium in some cases.

C. Micro Findings

  1. Ectopic nests of endometrial glands enclosed within a spindle cell stroma between the muscle bundles of the myometrium.

  2. The nests should be one low power field or more (2 to 3 mm) below the endomyometrial junction.

D. Others:

  1. DDx:

    Ectopic endometrial tissue in the myometrium of uterus: adenomyosis.

    Ectopic endometrial tissue in abnormal location outside the uterus: endometrisis.

E. Reference

  1. Robbins Pathologic Basis of Disease, 6th ed.  P.1057.




Fig. 76-1 (LP)Several ectopic islands of endometrial tissue embedded in the myometrium.




Fig. 76-2 (LP)Islands of endometrial tissue and myometrium.




Fig. 76-3 (HP)Endometrial tissue includes endometrial glands and endometrial stroma in this section.