Benign multicystic peritoneal mesothelioma (BMPM) is a rare condition, more common in females of reproductive age, which arises from the peritoneal mesothelium. A 33-year-old male presented to our unit with abdominal pain and constipation. His past medical history included a previous unilateral nephrectomy for Wilms’ tumor and the previous incidental finding of some intra-abdominal cystic formations at the level of the mesentery. After performing a CT scan, an exploratory laparotomy was done and a voluminous cystic mesenteric mass, composed of 3 confluent formations, was observed. Some other similar but significantly smaller lesions were found. An en bloc resection of the mesenteric mass together with the corresponding intestinal loops, an appendicectomy, and some peritoneal biopsies were performed. The postoperative period was complicated by a peritonitis due to dehiscence of the intestinal anastomosis, which required another operation, and a delayed return of normal bowel function, which was resolved through prokinetic therapy. Through histological examination, a BMPM was diagnosed. At 8 months of follow-up, the patient is free of symptoms. BMPM exact etiopathogenesis still remains uncertain. Given his high recurrence rate, a long-term follow-up is recommended.
Benign multicystic peritoneal mesothelioma (BMPM) is an uncommon benign tumor that arises from the peritoneal mesothelial cells. It usually affects females of reproductive age. Its etiopathogenesis is still controversial [
In this paper, we report a case of BMPM in a male patient submitted to unilateral nephrectomy for a right-sided Wilms’ tumor when he was a child.
A 33-year-old Caucasian male presented to our surgical unit after 3 days of progressively worsening abdominal pain. The patient also reported the onset of constipation for some days, but he denied any associated nausea or vomiting.
His past medical history included a right-sided Wilms’ tumor treated with unilateral nephrectomy when he was 2 years old. Moreover, during the follow-up for this pediatric tumor, some progressively growing intra-abdominal cystic formations, localized at the level of the mesentery, have been incidentally identified.
Physical examination revealed a hypogastric mass and diffuse abdominal tenderness without abdominal distension.
The patient underwent an abdominal CT scan (Figure
BMPM on CT scan. Contrast-enhanced CT scan shows the presence of 3 contiguous, communicating, and thin-walled cystic formations located at the level of the mesentery. The mass with larger dimensions is the most ventral one, and it is localized in contiguity with the abdominal wall, in the subumbilical region.
Due to worsening symptoms, an exploratory laparotomy was performed and a voluminous cystic mass, composed of 3 confluent formations, with a major axis equal to about 10 cm, and incorporated in the mesentery of the last ileal loops, was observed (Figure
Intraoperative images of BMPM. Voluminous cystic mass incorporated in the mesentery of the last ileal loops detected during the operation.
The postoperative period was complicated, on the 8th postoperative day, by a circumscribed peritonitis due to dehiscence of the ileoileal anastomosis. The patient was therefore submitted to another operation. On this occasion, a resection of the previous anastomosis and an ileocecal resection with ileo ascending colon anastomosis were performed.
Moreover, the postoperative period was complicated by a delayed return of normal bowel function which was resolved through prokinetic therapy with levosulpiride and neostigmine methylsulfate. The patient was finally discharged 33 days after the first operation in good condition.
Through histological examination a benign multicystic peritoneal mesothelioma was diagnosed.
At 8 months of follow-up, the patient is free of symptoms.
BMPM was first described in 1928 by Plaut, who incidentally observed some pelvic cystic lesions during surgery for uterine leiomyoma [
This tumor usually affects females of reproductive age, and it is very rare in males [
Its etiopathogenesis is still debated [
BMPM has a predilection for the pelvic peritoneum [
Surgical specimen of BMPM. Voluminous cystic formation, composed of 3 confluent masses, with a major axis equal to about 10 cm and filled with straw-coloured fluid observed after resection.
BMPM is often discovered incidentally; in fact, as in our case, the majority of patients are asymptomatic until this tumor is quite large to cause a mass effect on other organs [
Physical examination can reveal abdominal distension, abdominal tenderness, and one or more palpable abdominal and/or pelvic masses [
Preoperative diagnosis is challenging [
Ultrasound (US) and, above all, CT scan are useful for diagnosis. In addition, MRI can also be employed [
Definitive diagnosis requires histological examination, and if any doubts remain, positive immunohistochemical staining of the mesothelial cells for calretinin confirms the diagnosis [
To date, the main therapy is surgery [
Prognosis appears to be very good [
BMPM has an extremely low potential of malignant transformation. In literature, there are only 2 cases of malignant transformation [
In conclusion, a new rare case of benign multicystic peritoneal mesothelioma, uncommonly occurred in a male patient, has just been described. BMPM exact etiopathogenesis still remains unclear. The most probable theory, as also suggested by our experience, seems to be the one which considers this tumor as the result of a persistent inflammatory status involving the peritoneum, as in case of previous abdominal operations. To date, despite the various combinations of therapies which have been tested, the local recurrence rate remains high. Thus, a long-term follow-up after treatment is highly recommended.
The authors declare that there is no conflict of interest regarding the publication of this article.