Original contributionPostablation neuroma of the myometrium—a report of 5 cases☆,☆☆
Introduction
Chronic pelvic pain is common, and may lead to hysterectomy. Reasons for chronic pelvic pain include endometriosis, adenomyosis, fibroids, pelvic adhesions, pelvic inflammatory disease, ovarian cysts, and polycystic ovaries, but oftentimes an explanation is lacking [1], [2], [3], [4]. Recent studies have suggested that an increase in innervation of the inner myometrium and endometrium may play a role in the pathogenesis of chronic pelvic pain [2], [3], [5]. This led us to evaluate our own experience, and to consider whether pathologists should routinely evaluate for uterine nerves in hysterectomies for pelvic pain.
In 2005, Atwal et al demonstrated an increased number of nerve fibers in the inner wall in women with advanced endometriosis [2]. They also found increased nerve fibers in women with chronic pelvic pain but without endometriosis. Since their control group was uteri removed for painless conditions, this suggested that the endometriosis itself was not the cause of pain. In 2010, Zhang et al found increased nerves in the endometrium and inner myometrium in women with painful adenomyosis and painful fibroids [3]. Again, the increased nerves were not in the lesions themselves, but in adjacent tissues.
Large areas of normal myometrium can lack demonstrable nerve fibers [5]. Normal uterine nerves in nulliparous women are mainly in three distributions: the subserosa, in sparse neurovascular bundles coursing through the myometrium, and at the endomyometrial junction [5]. Based on prior literature [2], [3], [5] and our personal experience, we classify 5 or more nerve fibers/field at 200× magnification as abnormally increased (Fig. 1A).
It has been reported that 30% of multiparous uteri had foci of abnormal clusters of small nerves, called microneuromas, whose clinical significance is not established [5]. Microneuromatous clusters may have 10 or more nerve fibers. In our experience (unpublished), microneuromas are associated with naturally occurring outer wall scars (fibrosis uteri) (Fig. 1B and C). Fibrosis uteri generally has a component of elastosis, and it was a matter of common knowledge 40 years ago that this was a marker for parity; but many recent texts have failed to cite the references to naturally occurring myometrial scars that date back more than a century [6], [7].
Since starting to evaluate hysterectomies for pain with immunostains for nerves, we encountered 5 cases in a single year with a striking pattern of uncountable small nerve proliferation (dozens or hundreds) in the myometrium. All 5 had previously undergone ablation for abnormal uterine bleeding; and all 5 ablations had gone quite deep, focally ablating the inner third of the uterine wall (Fig. 2). The purpose of this article is to describe 5 cases of postablation neuromas as the likely cause of pelvic pain, leading to hysterectomy.
Section snippets
Case
A 47-year-old woman had an endometrial ablation in 2007. She also had progressively worsening chronic pelvic pain since 2004, which increased after the ablation, leading to a hysterectomy in 2012. The 40-g uterus was symmetrical with a 1.4 cm myometrium with no gross lesions or masses. Microscopically, there was no residual endometrium (Fig. 3A). Large vessels, markers for the junction of middle and outer third of the wall, were seen close to the surface scar; indicating that this had been a
Discussion
This approach to analyzing hysterectomies for benign disease is based on a modern understanding of the uterus as a complex muscular organ with great histologic heterogeneity [8], [9], [10]; baseline myometrial tone [15], [17]; contractions during menstrual cycles [18], [19], [20], [21]; ability to contract both downward and upward towards either cornu [21]; perivascular weak points in the wall as seen in the gastrointestinal tract [22]; increased intramural pressure in the presence of bulky
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2022, Annals of Diagnostic PathologyCitation Excerpt :Tissue damage leads to granulation tissue, which has nerve growth factor. Post-ablation neuromas have been demonstrated when pain increased after a prior ablation [4]. Fig. 3c shows an outer wall bulge that was palpable on physical exam, simulating a fibroid.
Neurological disorders after hysterectomy: From pathogenesis to clinical manifestations
2022, Epilepsy and Paroxysmal ConditionsA Comparison of Hysterectomies for Bleeding With Hysterectomies for Pain
2020, International Journal of Surgical PathologyThe Autonomic Innervation and Uterine Telocyte Interplay in Leiomyoma Formation
2019, Cell TransplantationA Review and Reconsideration of Nonneoplastic Myometrial Pathology
2018, International Journal of Surgical Pathology
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This study was supported by a grant from the Genesee Hospital Foundation and the Rochester General Hospital Foundation. We thank Dawn Riedy, MD, for helpful suggestions.
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Competing interests: The authors declare no conflict of interest.