Abstract
Introduction:
Well-differentiated papillary mesothelioma (WDPM) is a very rare neoplasm. Most of WDPM are asymptomatic and are often incidentally detected during surgery. This report describes a case of WDPM of the peritoneum unexpectedly diagnosed in a male with a spontaneous intraperitoneal bladder rupture.
Case presentation:
A 65-year-old male presented to our Emergency Department in November 2019 with a two-day history of anuria, abdominal pain, distention, and sepsis. The CT scan reported a large amount of extra and intraperitoneal free fluid. The CT cystogram showed bladder perforations on the dome and on the left lateral wall which was repaired through exploratory laparotomy. Intraoperatively, we encountered extensive suppurative peritonitis with large fibrino-purulent exudation. The purulent perivesical peritoneum was dissected and sent for histopathological examination which unexpectedly resulted in WDPM of the peritoneum.
Conclusion:
Although we can’t affirm with certainty, this case would seem to suggest that WDPM had played a role in patient’s clinical presentation. However, further research is necessary to draw stronger conclusion.
Introduction
Well-differentiated papillary mesothelioma (WDPM) is a very uncommon subtype of mesothelial neoplasm that is often incidentally detected during abdominal surgery. WDPM is apparently unrelated to asbestos and most commonly occurs in women during the reproductive years.1,2 To the best of our known, no more than 50 cases have been reported in the literature. 3
Concerns have been raised regarding WDPM origin, considering it as a reactive mesothelial hyperplasia or a benign tumor, up to a precursor of epithelial malignant mesotheliomas. However, recent preliminary researches on genomic sequencing seem to suggest the distinct nature of WDPM, with unique histopathological and genetic patterns. 2
Primarily arising from the peritoneal surfaces of the abdomen and pelvis, WDPM can rarely occur in the pleura and pericardium. Occasionally, they can originate from the tunica vaginalis of the testis as a paratesticular mass. Short series and case reports are present in Literature focusing on the rarity of this histopathological finding and on the difficulty in clearly categorizing the cases either as WDPM or malignant mesothelioma. 4
There is still considerable controversy surrounding the differential diagnosis between WDPM and malignant mesothelioma, being the latter more aggressive and prognostically worse. The major difficulty usually regards the initial steps of the assessments, when the invasive growth cannot be completely established. 4
Although generally considered a tumor of indolent behavior, WDPM may range from benign course to disseminated and recurrent disease resulting in death. 5
There is no general agreement on the disease course and, consequently, the treatment is not well-established ranging from observation alone or systemic chemotherapy and excisional biopsy. Generally, WDPM prognosis is favorable, with an indolent post-surgical clinical behavior 1 and a median survival of 12 years. 3
We report a case of WDPM of the peritoneum incidentally detected in a male presented at our Institution with a spontaneous intraperitoneal bladder rupture.
Case presentation
A 65-year-old male presented to our Emergency Department (SS Biagio e Cesare Arrigo Hospital—Alessandria, Italy) in November 2019 with a two-day history of anuria accompanied by abdominal pain and distention.
Review of his medical history showed that in July 2019 he had undergone transurethral resection of a low-grade pTa bladder tumor (TURBT), and subsequently a single early intravesical instillation of Mitomycin C (MMC) in another Institute. According to the operative report, the tumor size was about 1.5 cm and no obvious bladder wall perforation was mentioned. The patient referred that the urethral catheter removal occurred on postoperative day 2.
No pre- or post-operative imaging was available. A prostate volume of about 70 mL measured by transrectal ultrasound (TRUS) was only reported.
Moreover, he described moderate lower urinary tracts symptoms (LUTS) according to the International Prostate Symptom Score. 6
In particular, he had noticed his urinary stream slowed during the last months, but denied difficulty in emptying the bladder, urine flow intermittency, nocturia, or severe urgency. Otherwise, his history was unremarkable.
When he presented to our Institution, the laboratory workup revealed a white blood cell count of 23.3 × 109/L, serum creatinine 7.04 mg/dL, C-reactive protein 32.14 mg/dL. He did not report any recent significant traumatic accident.
CT scan revealed bilateral mild excretory system dilatation and the presence of a moderate amount of extra and intraperitoneal free fluid. Furthermore, diffuse and irregular bladder wall thickening, in particular on the right side, was detected. The urinary tract mildly obstruction was attributed to the thickened bladder wall and to the irregular perivesical tissue.
Bladder perforation on the dome and on the right lateral wall was suspected at a CT cystogram (shown in Figure 1). We didn’t know if it corresponded to the site of the previous resection.
Bladder perforation on the dome and on the right lateral wall at a CT cystogram.
Considering both the patient’s doubtfulness to undergo surgery and his clinical stability, we firstly opted for a conservative approach.
A 22F Foley catheter was placed draining about 100 mL of purulent urine.
In a few hours hemodynamic problems occurred so catecholaminergic therapy, fluid resuscitation and antibiotic treatments were administered stabilizing the patient’s vital signs. The following day patient’s health newly deteriorated with severe lower abdominal tenderness and signs of peritonism so he consented to exploratory laparotomy.
Intraoperatively, we encountered extensive suppurative peritonitis with large fibrino-purulent exudation. The perivesical peritoneum was tenaciously adherent to the intestinal loops and the bladder wall resulted very friable with multiple fissures. The abdominal cavity was further explored, and peritoneal lavage was carried out. Debridement of the purulent perivesical peritoneum was performed and perycistic tissue was sent for histopathological examination. The bladder was repaired as far as possible.
Unexpectedly, the histopathological evaluation revealed WDPM of the peritoneum (shown in Figures 2 and 3).
Histology displays fibrous papillae lined by a single layer of cuboidal or flat mesothelial cells without significant cytologic atypia. Mitotic figures are absent (Hematoxylin and Eosin, ×10).
The cells are positive for calretinin (immunohistochemical stain for calretinin, ×20).
After surgery, the patient was transferred to the Intensive Care Unit where he developed acute heart failure within 48 h after admission. Echocardiography revealed a left ventricular ejection fraction of only 22% with apical hypokinesis and severe aortic regurgitation. Although further cardiological tests and eventually valvular surgery were strongly recommended, he refused any other diagnostic and therapeutic procedure. A negative cystography for extravasation performed 30 days after the surgery allowed the Foley catheter removal.
Unfortunately, the following week the patient newly presented to our ED complaining of fatigue, oliguria, and abdominal discomfort. The catheter was replaced draining purulent urine. The CT-cystogram showed bladder rupture and free fluid in the peritoneal cavity. Conservative management was provided. Another attempt to catheter removal failed at 40 days. He refused any surgical intervention and insisted on conservative care. The severe cardiovascular comorbidities led to his death few days after the admission.
Discussion
WDPM is a very rare condition. Usually asymptomatic and incidentally detected during surgeries. 7
Acute abdomen is a very uncommon presentation of peritoneal WDPM, with less than 10 cases reported in literature, to date. The main causes described of acute abdomen are hemoperitoneum due to bleeding of one of the WDPM lesions and intestinal obstruction. 7
In our case, the patient presented with a two-day history of anuria accompanied by abdominal pain and distention. Spontaneous urinary bladder perforation was suspected based on instrumental investigations.
After an attempt at conservative care, the patient underwent surgery and, unexpectedly, the perycistic tissue histopathological examination revealed WDPM.
Spontaneous bladder rupture is a rare occurrence, with an incidence of 1: 126,000 and a mortality rate of 47%, 8 and it is often the result of an underlying pathology such as inflammation, infections, retention of urine, pelvic irradiation, or invasive tumor. 9
To the best of our knowledge, no cases of spontaneous urinary bladder perforation as primary symptom of WDPM are reported in literature.
Although we can’t affirm with certainty, we hypothesize that WDPM played a role in patient’s clinical presentation. Indeed, the intraoperative findings may be considered as underlying factor behind bladder wall weakness and eventually rupture. Naturally, there may be other possible explanations. Considering patient’s history of urothelial bladder cancer, we reasonably highlight that TURBT and the early intravesical instillation of MMC 4 months earlier are both confounding factors regarding the genesis of spontaneous bladder perforation, making this situation hardly replicable.
According to patient’s medical history, urinary retention was excluded, and, in-any-case, retention of urine alone rarely causes spontaneous urinary bladder perforation. 9
Finally, it may be also assumed that spontaneous bladder rupture could be a delayed complication of TURBT performed 4 months earlier for a low-grade pTa bladder tumor.
Bladder wall perforation is considered the second most frequent complication of TURBT, with a presumed incidence of 1.3% to 5%. 8 Anyway, only few cases of delayed perforation after TURBT are reported in Literature and they are usually associated with muscle invasive bladder cancer. 10
On the other hand, WDPM, determining tenacious adherences between pericystic tissue and perivesical peritoneum, may have hidden an early perforation during TURBT, revealing it 4 months later.
The real cause of the patient’s spontaneous bladder rupture remained unclear, although it cannot be ignored the unexpected histopathological finding. The most reasonable hypothesis is that multiple causes contributed to the patient’s clinical presentation.
Conclusion
Well-differentiated papillary mesotheliomas are uncommon mesothelial tumors, usually asymptomatic. The most common presentation of peritoneal WDPM is acute or chronic abdominal pain.
Our experience would seem to suggest that spontaneous urinary bladder perforation is likely to be a primary manifestation of WDPM or, more reasonably, an underling factor contributing to the bladder rupture.
Our hypothesis clearly has some limitations. Never-theless, we believe that our work could be the starting point for future research. Further investigations on this topic are necessary to draw stronger conclusion.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Statement of ethics
Written informed consent was obtained from the patient’s next of kin for publication of this case report and the accompanying images.
