Omental tumors are relatively rare, typically originating from adipose tissue, blood vessels, and lymphatic vessels within the omentum. In cases of leiomyomas from the greater omentum, PLs might play a role in their pathogenesis[5]. The pathological assessment in our case identified the omental mass as "uterine leiomyoma." Given the patient's prior laparoscopic myomectomy, it's likely that residual uterine leiomyoma tissue attached to the greater omentum, depending on its vascular supply for nourishment. The elongated pedicle of the mass was prone to multiple rotations, leading to acute abdominal pain. The characteristic clinical signs of parasitic leiomyoma torsion include the sudden onset of abdominal pain that intensifies over time[6], with subsequent infection from ischemic necrosis causing fever and increased inflammatory markers.
Literature search was conducted using the PubMed database with the keywords: “parasitic leiomyoma”, “parasitic myoma”, and “omentum”, identifying 12 English-language reports[2, 5, 7–16]. Detailed information regarding the size, number, and torsion status of PLs in the greater omentum, as well as patient age, symptoms, previous surgical history, and the use of a morcellator during surgery, was extracted from these studies. The average age at diagnosis was 39 years (range: 26–58 years). Natural postmenopause was reported in one patient. Pain was the primary symptom in seven cases (58.3%). Uterine leiomyoma-related surgeries had been performed in seven cases, including four laparoscopic myomectomies, two transabdominal myomectomies, and one combined laparoscopic myomectomy/total laparoscopic hysterectomy, with a morcellator used in five cases (71.4%). The average time between the initial surgery and the discovery of PL was 6.8 years (range: 0.6 to 13 years); five cases (41.7%) had no history of uterine leiomyoma-related surgeries. The average diameter of the leiomyomas was 13.3 cm (range: 3.8–34 cm), with eight cases (66.7%) presenting a single leiomyoma and four cases (33.3%) experiencing torsion. This review is summarized in Table 1, highlighting that intraperitoneal PLs primarily affect women of reproductive age. Although most cases are linked to previous uterine leiomyoma-related surgeries, especially those involving morcellators, it's crucial to also consider patients without surgical history. Owing to their rich blood supply from the omentum, these tumors can grow rapidly. Typically larger than PLs found in other locations, they may cause compression symptoms or even signs of intestinal obstruction, presenting with abdominal pain, bloating, nausea, vomiting, and discomfort. Additionally, the omentum's spaciousness allows for the possible torsion and necrosis of medium-sized or small-volume leiomyomas, leading to acute abdomen. These characteristics are key in distinguishing PLs in the greater omentum from those occurring in other areas.
Currently, there is no standardized treatment protocol for PL on the greater omentum. It shares the hormone dependence characteristic of uterine leiomyomas[17], making it less common in postmenopausal women[18–20]. A case study documented a 46-year-old female who underwent three surgeries within three years after laparoscopic subtotal hysterectomy due to recurrent PL. Ultimately, bilateral oophorectomy was performed to successfully terminate the recurrence, highlighting the significant role of hormonal levels in PL growth[21]. Research has shown that ER and PR are highly expressed in the nuclei of PL cells[21], leading to reports on the use of gonadotropin-releasing hormone analogs for PL treatment[22]. However, its unusual location and nonspecific clinical signs make differentiating PL from other pelvic and abdominal masses challenging. Therefore, securing a pathological diagnosis is essential before starting drug treatment. Moreover, differentiating between benign leiomyoma and malignant leiomyosarcoma poses challenges in cases of large tumors or suspected malignancy, making surgical resection the primary treatment for PL[23]. Matteo Bruno et al.[24] reported on the ultrasound-guided histological diagnosis and non-surgical treatment of a PL occurring twenty years after a total laparotomic hysterectomy and bilateral adnexectomy in a patient with multiple comorbidities, suggesting conservative non-surgical methods as an alternative treatment for select cases. However, biopsy false negatives can occur. If fibroids continue to grow or rapidly increase in the short term, surgical intervention should be considered. Unlike PL in other locations, PL of the greater omentum tends to have increased mobility and larger size, leading to severe complications such as organ compression, intestinal obstruction, or torsion and necrosis, making surgical intervention the preferred treatment for nearly all documented cases.
The literature strongly indicates a link between PL and residual leiomyoma fragments from prior surgeries[25]. As such, prevention should be a primary focus, requiring surgeons to be vigilant about the potential for iatrogenic PLs on the greater omentum. This involves careful collection and fragmentation of leiomyomas during surgery, along with a thorough inspection of the abdominal cavity before concluding the operation. Strategies include the early placement of a specimen collection bag in the peritoneal cavity during myomectomy to capture small leiomyomas; fragmentation of leiomyomas within this bag to prevent tissue dispersion; and, after adjusting head elevation and hip depression, comprehensive irrigation of the pelvic cavity and puncture site with a significant volume of warm saline solution (recommended: 2000–3000 mL), followed by a thorough inspection to ensure no tissue fragments are left behind.
Moreover, the importance of regular postoperative imaging for early detection of potential issues cannot be overstated. Reports have noted the shortest recurrence time post-surgery as four months, with a PL reaching up to 7.5 cm in diameter[21]. For patients with a history of uterine fibroids and presenting omental masses, the possibility of PLs should be considered. Immediate pathological examination during surgery is critical to prevent unwarranted expansion of the surgical scope and potential additional harm to the patient. It's also vital to acknowledge the potential for PLs to be present across various organ surfaces and to thoroughly explore the extensive areas within the pelvic and abdominal cavities during surgery. This includes hidden regions like the intestinal surface, omentum, peritoneum, and even scars from previous abdominal surgeries. In our case, the largest PL was found on the omentum surface. A more detailed investigation revealed two additional PLs measuring between 0.5 and 2.0 cm in diameter on the bladder peritoneal reflection and left ovarian surface, highlighting the need for a comprehensive examination of both pelvic and abdominal cavities.