Disseminated peritoneal leiomyomatosis: A case report

Abstract

This report describes the case of a patient in her early 40s with a history of laparoscopic myomectomy who presented to the Beijing Shunyi District Maternal and Child Health Hospital (Beijing, China) in December 2024 with menstrual disturbances and a pelvic mass. The patient had disseminated peritoneal leiomyomatosis, a rare benign neoplastic condition characterized by multifocal smooth muscle nodules on the peritoneal surface. Its nonspecific clinical and radiological features often lead to misdiagnosis as malignant peritoneal carcinomatosis. Pelvic magnetic resonance imaging revealed a 9.5-cm cervical mass, an 11.4-cm right pelvic mass, and multiple T2-hypointense uterine lesions, with the largest lesion measuring 14.9 cm. The patient underwent a total laparoscopic hysterectomy with bilateral salpingectomy and resection of multiple mesenteric tumors, with an aggregate specimen weight of 4600 g. Histopathological examination confirmed benign leiomyomatosis, thereby establishing the diagnosis of disseminated peritoneal leiomyomatosis. This case demonstrates a causal link between uncontained morcellation and disseminated peritoneal leiomyomatosis, underscores the role of magnetic resonance imaging T2 hypointensity in differentiating this benign condition from malignancies such as leiomyosarcoma, and confirms surgery as the cornerstone of management when fertility is not a concern. Long-term surveillance remains imperative due to risks of recurrence and rare sarcomatous transformation. Written informed consent was obtained from the patient for treatment and publication, and all patients details have been deidentified to protect anonymity.

Introduction

Initially reported by Willson and Peale in 1952 and later named by Taubert et al. in 1965, ¹ leiomyomatosis peritonealis disseminata (LPD) is a rare benign condition defined by the presence of numerous smooth muscle nodules on the peritoneal surface. This disease remains exceedingly rare, with approximately 200 cases reported worldwide, ² resulting in limited epidemiological data. LPD is often clinically silent or presents with nonspecific symptoms and is most commonly an incidental finding during imaging or surgery. ³ The rarity of LPD has precluded the establishment of a standardized management protocol. Therefore, treatment must be individualized and currently revolves around two main modalities: surgical intervention and endocrine therapy. This report details a case of LPD, with an emphasis on its pathogenesis, diagnostic challenges, and therapeutic approaches.

Case presentation

The reporting of this case conforms to the Case Report (CARE) guidelines. ⁴ A woman in her early 40s presented to the Beijing Shunyi District Maternal and Child Health Hospital in December 2024 with a 2-month history of menstrual irregularities and a palpable pelvic mass. Initial transvaginal ultrasound revealed multiple masses: a 9.5 ×7.5 × 7.2-cm hypoechoic mass in the posterior cervical lip, an 11.4 × 8.5 × 7.3-cm inhomogeneous hypoechoic lesion in the right pelvis, and a 7.5 × 6.1-cm mass on the left side of the uterus, associated with endometrial thickening (4.9 cm). Color Doppler flow imaging indicated internal vascularity with a resistance index of 0.5. The levels of all serum tumor markers were within the normal ranges.

Her past surgical history included a laparoscopic myomectomy (2011) and two full-term cesarean sections (in 2012 and 2017). Physical examination revealed a myoma-like mass in the left vaginal fornix and irregular uterine enlargement with broad ligament nodularity (8.0 × 7.0 cm); a Mirena® IUD was properly positioned. As illustrated in Figure 1, pelvic magnetic resonance imaging (MRI) demonstrated numerous leiomyomas affecting the uterus (International Federation of Gynecology and Obstetrics (FIGO) types 5–8), cervix, and bilateral broad ligaments. The largest lesion, located in the right broad ligament (149 × 59.5 ×71.5 mm), was T1 hypointense and exhibited heterogeneous T2 hypointensity with internal hyperintense foci, consistent with degeneration. The scan also revealed secondary cervical canal stenosis, rectal compression, and minimal pelvic fluid.

Figure 1.

Pelvic MRI findings in a patient with disseminated peritoneal leiomyomatosis (LPD). (a) Axial T2-weighted image at the level of the cervix, showing a large, lobulated hypointense mass (arrows) occupying the right hemipelvis and (b) axial T2-weighted image at a higher pelvic level, revealing multiple additional small hypointense nodules (arrowhead) scattered along the peritoneal surface. MRI: magnetic resonance imaging.

In accordance with the patient’s request for definitive therapy and completed family planning, we performed total laparoscopic hysterectomy and bilateral salpingectomy. Intraoperative findings (Figure 2) included extensive sigmoid adhesions, an 8-cm left broad ligament myoma extending to the pelvic sidewall, and a lobulated presacral mass (15 × 12 × 9 cm) with dense rectal adhesions. Additional mesenteric nodules were excised during adhesiolysis. Gross examination revealed an 8-cm broad ligament myoma and three mesenteric leiomyomas (largest 15 × 12 × 9 cm), totaling 4600 g in weight. A diagnosis of LPD was confirmed on histopathology, which demonstrated benign leiomyomatosis across all resected specimens (uterus, cervix, and mesentery). The patient remained well during the postoperative period and was discharged on day 7. Long-term surveillance was planned without initiating adjuvant therapy, given the established risks of recurrence and sarcomatous change. Crucially, no recurrence was observed at the 1-, 3-, or 6-month postoperative follow-up.

Figure 2.

Intraoperative laparoscopic view of disseminated peritoneal leiomyomatosis (LPD). (a) Intraoperative laparoscopic view of the pelvic cavity, showing multiple, well-circumscribed, smooth-surfaced nodules (arrows) disseminated over the sigmoid colon mesentery and (b) close-up view of a cluster of nodules near the left pelvic sidewall, illustrating their benign macroscopic appearance.

Discussion

First described in the literature by Willson and Peale and later named by Taubert et al.,^1,2 LPD is a rare benign neoplasm characterized by widespread peritoneal implants that can mimic malignant dissemination. With fewer than 200 cases reported globally, ³ it overwhelmingly affects women of reproductive age, with only sporadic cases documented in postmenopausal women and men. ⁵

Although the exact etiopathogenesis of LPD is incompletely defined, four principal theories have been proposed. One leading hypothesis is the metaplasia of subperitoneal mesenchymal stem cells, according to which, LPD nodules are derived from pluripotent stem cells with the capacity to become smooth muscle or endometrial tissue.^3,6 The frequent association between LPD and endometriosis lends credence to this idea, as the lesions commonly contain both metaplastic smooth muscle and endometrial constituents.^6–8 A case report by Yu et al. ⁸ involving a nonsurgical patient with omental and mesenteric nodules showing dual differentiation provides further evidence in support of this theory.

In contrast, the iatrogenic theory attributes LPD to the mechanical dissemination of tissue fragments during laparoscopic myomectomy, especially when uncontained morcellation is used. The reported postoperative incidence of this complication ranges from 0.1% to 1.0%.^9,10 Molecular evidence strongly supports this theory. Studies by Miyake et al. ¹¹ and Sekulic et al. ¹² have demonstrated clonal identity between the original uterine leiomyomas and the resulting LPD implants through X-chromosome inactivation and cytogenetic analyses. This association is further supported by a clinical series by Li et al. ¹³ wherein 11 of the 13 LPD patients had a history of laparoscopic myomectomy, with 2 patients even exhibiting implants at the trocar insertion sites.

The hormonal influence on LPD is well-documented. This theory is supported by its frequent occurrence in high-estrogen/progesterone environments, such as pregnancy, during hormone therapy, or in the context of estrogen-secreting tumors.^7,9 Additional evidence includes the observed spontaneous regression of lesions after menopause ⁹ and the nearly universal expression of estrogen receptors (ERs) and progesterone receptors (PRs) in these nodules. ¹⁴ It is hypothesized that hormones promote both metaplastic changes in stem cells and the growth of iatrogenically implanted tissue.^8,15,16

Finally, a rare genetic predisposition is suggested by a familial cluster reported by Halama et al., ¹⁷ which exhibited an autosomal dominant inheritance pattern. However, the definitive underlying genetic mechanisms require validation in larger studies. The history of laparoscopic myomectomy in our patient strongly supports an iatrogenic pathogenesis, which is consistent with the prevailing molecular evidence.^11,12

An essential aspect of managing LPD is its differentiation from malignant conditions, particularly leiomyosarcoma. In the present case, the preoperative clinical and radiological features—including the well-circumscribed nature of the masses and characteristic T2 hypointensity on MRI—were highly suggestive of benign leiomyomatosis, and there was no strong suspicion for leiomyosarcoma. However, if malignancy was suspected due to features such as rapid growth, invasive borders, and necrotic components, a more rigorous diagnostic approach would have been imperative. This would include intraoperative frozen section analysis to guide the extent of surgery, followed by comprehensive surgical staging and en bloc resection without morcellation, akin to the management of soft tissue sarcomas, to prevent iatrogenic tumor dissemination. ¹⁸

Patients with LPD are frequently asymptomatic or present with nonspecific complaints such as abdominal pain, distension, and symptoms of mass effect (e.g. ureteral and intestinal obstruction).^5,9,15,19 Consequently, imaging becomes crucial for diagnosis. Although ultrasound may detect multifocal hypoechoic nodules ²⁰ and computed tomography (CT) can visualize solid lesions, ²¹ MRI is particularly valuable due to its ability to show pathognomonic T2 hypointensity, mirroring the appearance of typical uterine leiomyomas. ¹ Conversely, the discriminatory value of positron emission tomography (PET)/CT is limited, as it may demonstrate variable ¹⁸F-fluorodeoxyglucose (FDG) avidity, with SUV_max values reaching 26.4.^1,22 The preoperative MRI findings in our case provided essential diagnostic information, thereby establishing its pivotal role in the workup of suspected LPD.

Currently, there is no standardized treatment protocol for LPD. Therefore, management is individualized, with surgical resection forming the cornerstone of therapy. The surgical approach (laparoscopic or open) is determined by the extent and location of the lesions, with strict emphasis on avoiding morcellation to prevent iatrogenic dissemination. ⁷ Fertility-preserving surgery is a viable strategy for reproductive-age women,^1,3 whereas hysterectomy with bilateral salpingo-oophorectomy is advised for those without fertility desires or when malignancy cannot be ruled out. ³ Endocrine therapy is used as an adjuvant; options include gonadotropin-releasing hormone (GnRH) agonists (achieving regression within approximately 6 months), ¹² aromatase inhibitors, ²³ and other selective progesterone modulators. However, the use of ulipristal acetate has been discontinued due to its hepatotoxic profile,^23,24 requiring clinicians to seek alternatives. Consequently, our patient, considering her age, surgical history, and large tumor burden, was treated with a definitive laparoscopic hysterectomy–salpingectomy, consistent with established guidelines.^1,3

Conclusion

LPD is a rare, benign extrauterine condition for which surgical resection remains the cornerstone of therapy, with hormonal treatment acting as an adjuvant to reduce recurrence. Nonetheless, the documented risks of recurrence (5%–30%) and sarcomatous transformation (<5%) mandate diligent long-term patient monitoring. Future multicenter studies are needed to establish standardized global management guidelines.

Supplemental Material

sj-pdf-1-imr-10.1177_03000605251411771 - Supplemental material for Disseminated peritoneal leiomyomatosis: A case report

Supplemental material, sj-pdf-1-imr-10.1177_03000605251411771 for Disseminated peritoneal leiomyomatosis: A case report by Huiyi Tan, Xin Mi and Wei Liu in Journal of International Medical Research