Diagnosing Disseminated Peritoneal Leiomyomatosis: Malignancy-Like Presentation in a 59-Year-Old Woman

Introduction

Disseminated peritoneal leiomyomatosis (DPL) is a rare benign disease, often giving the appearance of metastatic ovarian or peritoneal carcinoma. The risk of malignant transformation is 2% to 5%. Diagnostic methods include computed tomography (CT), ultrasound, magnetic resonance imaging (MRI), and histopathological evaluation, which are essential for assessing disease extent and guiding treatment. Management strategies encompass surgical intervention, with a focus on minimizing iatrogenic risks, conservative approaches for asymptomatic patients, and advancements in hormonal treatments [1,2]. In 1952, the case of multiple peritoneal leiomyomas was initially documented by Wilson and Peale [3]. The prevalence of DPL is estimated to be less than 1 in every 10 million individuals, with approximately 200 reported cases documented in the existing literature [4]. The cause of the disease is unclear, and several theories have been proposed for DPL, including hormonal stimulation, iatrogenic factors, and genetic predispositions. DPL typically occurs in premenopausal women and is traditionally considered a benign condition [5]. Therefore, the risk of malignant transformation is extremely low. There have been a limited number of cases reporting malignant transformation of DPL in previous literature [6–11]. Little is understood about the pathogenesis or potential for malignant transformation of this condition. In this report, we present a case of DPL in a middle-aged female patient. Additionally, we conducted a literature review to analyze the clinical features, diagnosis, and pathogenesis of malignant transformation.

Case Report

A 59-year-old woman presented to our hospital with difficulty in defecation. The patient had been experiencing tenesmus and persistent vague abdominal pain for the previous 6 months. At presentation, the patient had experienced more pronounced persistent abdominal pain than before, especially after meals. The patient had a blood creatinine level of 1255 umol/L, suggesting that she may have had renal dysfunction. Due to her previous clinical presentation of hydronephrosis, she underwent bilateral ureteral stent implantation 12 days before presenting at our hospital. Medical history revealed that she had had uterine myomas confirmed by ultrasound and MRI, and had undergone a hysterectomy.

She did not have any previous history of cancer or other relevant medical conditions. Colonoscopy examination revealed a 10-cm stenosis at the entrance to the large intestine, with obvious mucosal congestion, stiffness, and disordered glandular structures occupying more than half of the abdominal cavity, and the endoscope could not pass through the lesion. Lower abdominal MRI revealed significant thickening of the bowel wall at the junction of the rectum and sigmoid colon and a mass high-density shadow at the left pelvic cavity (Figure 1). Positron emission tomography-CT (PET-CT) showed thickening of the rectum and sigmoid colon wall, with increased fludeoxyglucose (FDG) metabolism. The cells inside the lesion under the microscope were well-differentiated smooth muscle cells (Figure 2). However, other pathological studies found a small number of abnormal glandular cells and severe inflammatory changes in the rectal mucosal tissue. Additionally, there was an increase in FDG metabolism observed in the greater omentum, mesentery, cervix uteri, and left ischial area. The tumor marker test demonstrated elevated serum CA19-9 (79.49 U/mL; range <37), CA 50 (52.8 IU/mL; range <25), and CA 242 (57.9 IU/mL; range <20) levels. The CA125 was negative (13.67 U/mL, range <35). The immunohistochemical findings were CD117(−), DOG1(−), Des(+), SMA(+), Ki-67 (index 5%), S-100(−), h-cadesmon(+), Vim(+), SOX10(−), HMB45(−), Melan-A(−), ALK(D5F3) (−), ER(−), PR(−), ROS1(−), CK20(−), CDX-2(−), and SATB2(−). The diagnosis of DPL was considered in conjunction with her history and immunohistochemistry results; the patient had undergone surgery at another hospital. By 6 months after surgery, the patient had died.

Discussion

In this case, we believe that the etiology of DPL may have been related to various factors, such as changes in hormone levels and surgery. Although cases of malignant transformation are rare, they require adequate attention and more aggressive interventions in clinical practice. Most patients with DPL are asymptomatic, while a minority experience symptoms such as abdominal pain, abdominal distension, abnormal uterine bleeding, and even gastrointestinal manifestations [12,13]. Our patient had significant abdominal symptoms, and a proctoscopy revealed intestinal narrowing and inflammatory changes. Pathological examination showed a small number of abnormal glandular cells in the mucosa, which had not been documented in previous reports [14–16]. No specific serological markers had been found. The patient’s tumor marker test revealed elevated concentrations of CA19-9, CA 50, and CA 242; however, tumor markers were previously reported at normal levels in a similar case [17]. The underlying reasons for these increased values remain unknown. The tumors observed in previous cases of DPL with PET-CT scans showed mild to moderate affinity for FDG (SUVmax: 1.6–4.3) [18,19]. This can easily be confused with malignant tumors. A previously reported case of a 43-year-old woman who initially presented with right lower abdominal pain revealed the patient’s CT and MRI examinations showed multiple intraperitoneal soft tissue masses near the sigmoid mesentery, left accessory colon sulcus, and ascending colon. With the combination of peritoneal mass resection surgery, abdominal hysterectomy, and bilateral salpingectomy, the diagnosis of DPL was confirmed [20]. In addition, the case of a 41-year-old female patient with a history of laparoscopic myomectomy and pregnancy was reported. Multiple lumps were found in the patient’s abdomen, with no tenderness or other discomfort. Based on imaging examination and clinical manifestations, the preliminary diagnosis was gastrointestinal stromal tumor. However, pathological examination after surgery confirmed that it was DPL. The patient’s postoperative prognosis was good, and there was no recurrence during the follow-up period [4]. The clinical outcome for DPL is generally good; however, a study suggests that malignant transformation can occur in 2% to 5% of cases [21]. Only a limited number of reported cases have demonstrated DPL with malignant transformation, while the pathogenesis of this transformation remains unclear. Yamaguchi et al discovered a potential correlation between p53 overexpression and the development of malignancy [11]. Chiu et al suspect that epithelial-mesenchymal transition is a key process in malignant metastasis of DPL [17]. Currently, surgery is the mainstay of treatment. However, due to the rarity of DPL, there are no guidelines on the management of the disease; therefore, it is important to consider the unique circumstances of each patient when determining appropriate treatments. In some of the similar cases we presented earlier [4,20], the patients had a good prognosis without deterioration or recurrent metastasis, whereas the patient in this case had a very poor prognosis and a short overall survival after surgery. This case should cause clinicians to be more cautious about the diagnosis of patients with DPL, and to consider whether a more comprehensive examination is needed to confirm that there is no possibility of deterioration. Postoperative surveillance plays a crucial role in preventing malignant transformation.

Conclusions

In conclusion, this case demonstrates diagnostic challenges. The patient had previous clinical manifestations of hydronephrosis and had persistent non-specific gastrointestinal symptoms in the past 6 months, coupled with the uncertainty of imaging examinations, highlighting the possibility of misdiagnosis. This report emphasizes the importance of understanding the presentation and distribution of DPL, as it can mimic the deposition of malignant tumors. In clinical practice, it is necessary to integrate multiple detection methods, to confirm the benign or malignant nature of tumors.