Brosens J J, de Souza N M, Barker F G
Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, London, UK.
Lancet. 1995 Aug 26;346(8974):558-60. doi: 10.1016/s0140-6736(95)91387-4.
The myometrium is usually thought of as a homogeneous mass of smooth muscle fibres. However, magnetic resonance studies of the uterus have revealed two distinct zones--the subendometrial myometrium or junctional zone and the outer myometrium. The junctional zone is not only structurally but also functionally different from the outer myometrium. For instance, myometrial contractions in a non-pregnant woman originate exclusively from the junctional zone, and their amplitude, frequency, and direction depend on the phase of the cycle. Irregular thickening of the junctional zone has been proposed as the magnetic resonance criterion for the diagnosis of diffuse adenomyosis. However, this magnetic resonance appearance relies on the disruption of the inner myometrial architecture secondary to smooth muscle hyperplasia but does not provide proof of mucosal invasion of the myometrium. We postulate that adenomyosis is a dichotomous disease characterised primarily by disruption of the inner myometrial architecture and function, with secondary infiltration of endometrial elements into the myometrium under certain circumstances. This hypothesis focuses on the inner myometrium and may explain the high incidence of superficial adenomyosis in dysfunctional uterine bleeding.
子宫肌层通常被认为是由平滑肌纤维构成的均质团块。然而，对子宫的磁共振研究显示出两个不同的区域——子宫内膜下肌层或结合带以及外层肌层。结合带不仅在结构上而且在功能上都与外层肌层不同。例如，非孕期女性的子宫肌层收缩仅起源于结合带，其幅度、频率和方向取决于月经周期的阶段。结合带的不规则增厚已被提议作为磁共振诊断弥漫性子宫腺肌病的标准。然而，这种磁共振表现依赖于平滑肌增生继发的子宫肌层内部结构破坏，但并未提供子宫肌层黏膜浸润的证据。我们推测子宫腺肌病是一种二分性疾病，其主要特征是子宫肌层内部结构和功能的破坏，在某些情况下子宫内膜成分会继发浸润到子宫肌层。这一假说聚焦于子宫肌层内部，可能解释了功能失调性子宫出血中浅表性子宫腺肌病的高发病率。
