Journals | Policy | Permission

Journal of Clinical Gynecology & Obstetrics

Case Report

Volume 5, Number 1, March 2016, pages 32-36

Pseudomyxoma Peritonei: A Case Report of an Incidental Finding at Cesarean Section

Cancer during pregnancy is rare, occurring in approximately 1 in 1,000 women. The cancers most likely occurring during pregnancy are those of the breast, uterine cervix, ovary, lymphomas and the colorectum, in declining order [1]. Of the colorectal neoplasms, approximately 1% are appendiceal in origin [2]. Some of these tumors arise from mucin-2 expressing goblet cells and in some cases, the appendix may perforate and goblet cells proliferate throughout the abdominal cavity. Large volumes of mucinous material can rapidly amass within the peritoneum. This is a condition known as pseudomyxoma peritonei (PMP).

The case reported below is a rare presentation of an incidental finding of PMP at cesarean section. As Donegan (1983) [1] attests to, and this case illustrates, symptoms of cancer are too often mistakenly attributed to the changes of pregnancy.

A review of the literature in light of the case presentation is discussed. Suggestions are made regarding diagnosis and management of this extremely rare disease.

A 27-year-old nulliparous patient was found to have a right-sided 7.6 cm heterogenous adnexal mass on routine antenatal ultrasound (morphology scan) at 20 weeks gestation. She was given the tentative diagnosis of an ovarian dermoid cyst and a follow-up ultrasound was arranged at 28 weeks gestation. The follow-up ultrasound was subsequently abandoned given that the working diagnosis was a dermoid cyst, the patient was asymptomatic and the fetus was growing normally.

Aside from a reassuring review for decreased fetal movements at 31 weeks, her pregnancy continued uneventfully. At 36 weeks gestation, the fetus was found to be breech on a routine antenatal visit. This was confirmed sonographically and, at the same time, it was observed that the “dermoid cyst” had grown to 18 cm and was occupying the pouch of Douglas.

Following an unsuccessful external cephalic version, she was consented for an elective cesarean section and right ovarian dermoid cystectomy at 38 weeks. On the day prior to surgery, she attended hospital for an anesthetic assessment. She reported ongoing pelvic pain, exacerbated with movement, which was attributed to her dermoid cyst.

The following day, she underwent an elective cesarean section. Under spinal anesthetic, the abdomen was entered through a Pfannensteil incision and routine entry, and was found to be grossly abnormal. Both ovaries were enlarged, multicystic and mucinous. A right salpingo-oopherectomy and left ovarian cystectomy were performed. The appendix similarly demonstrated enlarged mucinous cysts. Cystic deposits were evident throughout the omentum and palpable over the right side of the liver and the right diaphragm. The findings were consistent with PMP.

Intraoperative pathology samples confirmed low grade mucinous adenocarcinoma likely of appendiceal origin. Following delivery of a healthy male infant, she made an uneventful postoperative recovery.

The subsequent staging CT abdomen showed a ruptured mucinous tumor of the appendix with no appreciable metastases within the liver, surrounding bone or beyond the peritoneal cavity. Low density material was associated with the left ovary and pouch of Douglas but it was unclear whether this was free fluid or tumor deposits.

The patient was referred to St George’s Hospital in Sydney for further assessment and management.

A plan was made for cytoreductive surgery. This was initially delayed for social reasons but at 6 months following her cesarean section, the patient underwent extensive cytoreductive surgery. She had extensive “jelly-like” disease intra-abdominally; the appendix was the obvious site of primary disease. Bilateral diaphragms, the liver surface, her pericardium and her pelvis were stripped of deposits. Due to the extent of disease, a splenectomy, cholecystectomy, right hemicolectomy, terminal ileectomy and greater and lesser omentectomy were performed. She then received 90 min of intraoperative intraperitoneal heated chemotherapy (mitomycin C at 41.5 °C). The peritoneal cancer index (PCI) score was 24. Early postoperative intraperitoneal chemotherapy (EPIC) was performed the following day.

Pathology results concluded low grade appendiceal mucinous neoplasm with perforation. The intraoperative peritoneal deposits confirmed low grade PMP equivalent to disseminated peritoneal adenomucinosis (DPAM).

At 5 weeks postoperatively, she developed a transient small bowel obstruction that was conservatively managed. By 3 months postoperatively, she had returned to her activities of daily living at home, was eating well, exercising and had returned to paid work.

At 5 months postoperatively, repeat CT demonstrated no residual or recurrent disease.

PMP is a rare condition with approximately 500 cases discussed in the medical literature [3]. To our knowledge, there are only four cases of this entity occurring in pregnancy, only one of which was discovered at cesarean section [4].

The notable Bohemian physician and pathologist, Carl von Rokitansky, first described PMP in 1842 [5]. The understanding of PMP pathogenesis has evolved considerably since then. As in our patient, the vast majority of cases are primary appendiceal mucinous neoplasms [6-8], but there are cases that have been related to an ovarian primary [9]. The pathologic process begins with neoplastic transformation of the appendiceal goblet cells that, upon appendiceal perforation, continue to proliferate into the peritoneal cavity. Through maintenance of mucin expression, intraperitoneal mucin amasses resulting in voluminous PMP [10].

The clinical presentation of PMP is highly variable and non-specific with up to 20% of cases diagnosed incidentally at laparoscopy or laparotomy [11, 12]. The most common symptom in both men and women is gradually increasing abdominal girth (Table 1) [13]. Twenty to thirty percent of patients will present with non-specific symptoms such as lower abdominal pain, pelvic pressure and nausea [14, 15]. Women often develop an ovarian mass, usually on the right side, which is commonly diagnosed at a routine gynecological examination, and men can have new-onset hernia as the primary complaint [13].

Click to view

Table 1. Frequency of Symptoms and Signs of Pseudomyxoma Peritonei [13]

Pregnancy can mask and misconstrue the interpretation of all these symptoms and signs.

In diagnosing PMP, CT appears to be the most useful diagnostic tool. Diffuse loculations with mucin deposits exhibiting densities higher than non-mucinous or typical ascites are suggestive of PMP. The mucin deposits are loosely adherent to underlying surfaces; therefore, there is characteristic sparing of motile viscera such as the small bowel, and accumulation over non-motile organs, such as the liver and spleen [13, 16, 17]. Visceral “scalloping” arising from mucinous compression and fibrosis of organs [18] is pathognomonic of PMP.

Though CT may be of most diagnostic utility, its use in pregnancy is heavily guarded. To complicate diagnosis further, imaging by ultrasound can be misleading because the mucinous ascites can be mistaken for free intraperitoneal fluid [12]. However, there are sonographic features that can assist the clinician in distinguishing PMP (Table 2). When surrounded by benign ascites, the bowel floats freely and demonstrates positional shifting. Conversely, in PMP the gelatinous mucin tends to fix the bowel in position [19]. Koyama et al suggested that the finding of ascitic septations should alert the experienced clinician to the possibility of PMP [20]. Certainly, ascites, if present, is typically complex with multiple foci of echogenicity reflecting the mucinous composition [21]. Thus, in contrast to benign ascites, PMP varies in its gravity dependence due to its organ adherence. Lastly, the scalloping of hepatic margins evident on CT can typically be seen sonographically as well [19].

Click to view

Table 2. Sonographic Features of Pseudomyxoma Peritonei

The role of tumor markers remains unclear but, as with most cancers of gastrointestinal origin, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are frequently elevated in appendiceal neoplasms [13].

Therefore, a step up approach to investigation of lesions identified during pregnancy appears to be the safest and most sensible. Sonography is effective in routine screening and follow-up. CT is crucial in surgical evaluation. The risk of teratogenesis after 15 weeks gestation is extremely low [22]. The risk of carcinogenesis is less clear but certainly a single abdominal CT scan falls well below the carcinogenic dose estimated for a fetus [22]. In retrospect, this should have been the follow-up our patient received of the “dermoid cyst” uncovered at routine antenatal scan at 20 weeks gestation. If surgery is warranted, this is often safest in the second trimester, when the risk of spontaneous abortion or preterm labor is least [23].

Classification of the PMP entity has been shrouded with controversy and lacks standardization.

In 1997, Ronnett and colleagues [7], based on the findings from 109 cases, devised a classification system for PMP based on malignant potential and histopathology results. Under this system, PMP is sub-classified into three groups, with cases in each group exhibiting homogenous histology. DPAM exhibits histologically benign peritoneal lesions that follow an indolent course progressing over several years. In contrast, peritoneal mucinous carcinomatoses (PMCAs), usually with signet ring morphology, exhibit poor cellular differentiation and a rapid aggressive clinical course. A refinement of Ronnett et al’s original classification introduced the third sub-classification of PMCA-I (intermediate) describing lesions that would behave like PMCAs but with a less aggressive course and therefore better survival outcomes.

Bradley et al [24] in a case series of 101 patients with PMP found no difference in survival outcomes at 1, 3 and 5 years between patients classified as DPAM or PMCA-I (but found PMCA patients had significantly worse clinical courses). Based on these findings and some confusion over terminology, they suggested classifying PMP as either low or high grade mucinous adenocarcinoma based on the grade of epithelium within the peritoneal mucin. In 2010, the American Joint Committee on Cancer (AJCC) and the World Health Organization (WHO) adopted Bradley’s classification system. However, it has not been widely adopted by the medical community and Ronnett’s revised classification remains commonly reported by pathology services.

The importance of accurate classification and terminology has implications for the management of this disease.

Traditionally, appendiceal neoplasms with associated PMP carried a median survival of 3 years [13]. Serial surgical debulking was the mainstay of management and was repeated until no further benefits for the patient were achieved. The treatment was largely considered to be a palliative one.

Over the last three decades, a new standard of care has emerged. The “Sugarbaker technique” involves extensive abdominal surgery comprised of peritonectomy, heated intraoperative peritoneal chemotherapy (HIPEC) and EPIC. Systemic chemotherapy is rarely indicated because lymphatic and hematogenous metastasis is rare in appendiceal neoplasms [12, 25]. It may be of use in patients with recurrent or progressive disease [26].

No double blinded trials have been undertaken to compare the traditional approach versus the Sugarbaker technique. However, with serial surgical debulking alone, only 3-4% of patients will be disease-free at 10 years [27]. In a case series of 60 patients managed according to the Sugarbaker technique, 70% of patients remained disease-free 10 years postoperatively [28]. Understandably, the treatment itself is risky. Butterworth and colleagues reported a morbidity and mortality rate of 56% and 11%, respectively associated with intraperitoneal chemotherapy [29]. Complications included prolonged ileus, enteric fistulae, pancreatitis, pulmonary embolism, chronic abdominal pain and intra-abdominal abscesses. Given the considerable risks involved with this procedure, it is imperative to assess suitability to this management.

Research is increasingly turning to the crucial role of mucin in the pathogenesis of this disease. Amini and co-workers explored several novel approaches to mucin production including glucocorticoids and COX inhibition amongst others [10]. This may present an adjunct area of treatment in the future.

Prognosis is dependent on the histologic grade of disease and whether operative cytoreduction is complete or not. In a case report of 385 patients, partial cytoreduction did not confer any survival benefit over grossly inadequate cytoreduction [13]. A review of 274 cases of PMP classified according to the AJCC/WHO criteria revealed a 5-year survival of 63% for low grade mucinous adenocarcinoma and 23% for high grade mucinous adenocarcinoma [30].

In our patient, a delay in definitive treatment undoubtedly allowed an increase in tumor volume to occur. Initial exploration of the abdomen at cesarean section gave a PCI of 6. Six months later, at the time of peritonectomy, the PCI was 24. However, since the disease was low grade and surgical cytoreduction was complete, minimal compromise in the prognosis was expected. Early identification of the histological grade of the disease and subsequent completeness of cytoreduction are imperative in prognostication of PMP.

If a pregnant patient, in their second trimester or beyond, is diagnosed with low grade disease, definitive treatment can be deferred until 34 - 35 weeks when the infant can be delivered safely. If a cesarean is obstetrically warranted at this time, a vertical incision carries a lower risk of mucin deposits seeding into the abdominal wall [23]. Haase and colleagues reported a case of a patient diagnosed with PMP at 17 weeks gestation. Pregnancy was preserved till 35 weeks gestation and she underwent cytoreductive surgery at 2.5 weeks post-delivery. At 5-year follow-up, the patient remained disease-free [23].

Conversely, if a pregnant patient in their second trimester is diagnosed with high grade disease, definitive treatment should not be delayed and termination of the pregnancy should be considered. In a Japanese case study, a patient diagnosed with PMP at 27 weeks gestation underwent cesarean section at 34 weeks gestation in consultation with the family, neonataologists and obstetricians. Although the patient was still alive 6 months postoperatively, her cancer had continued to progress [20].

An index of suspicion should be maintained with all lesions identified during pregnancy. Serial sonography is appropriate. CT scanning and surgical exploration may be necessary in rare cases. This can be delayed to later in the pregnancy in most forms of PMP but should not be delayed in patients with rapid progression of disease. Surgical cytoreduction, intraperitoneal chemotherapy and EPIC appear to be the most effective course of management. Assisted reproduction strategies should be offered as it may be a necessity in achieving future pregnancies.

Conflicts of Interest

All the authors declare no conflicts of interest.

Author Note

The PCI grades peritoneal disease based on the extent of peritoneal surface involvement. The abdominal-pelvic region is divided into 13 regions, each of which is given a score out of 3 depending on disease involvement. The PCI is hence out of 39. In typically non-invasive diseases such as PMP, the PCI bears little prognostic value but serves to score the completeness of cytoreduction.

1. Donegan WL. Cancer and pregnancy. CA Cancer J Clin. 1983;33(4):194-214.
   doi pubmed
2. Moran BJ, Cecil TD. The etiology, clinical presentation, and management of pseudomyxoma peritonei. Surg Oncol Clin N Am. 2003;12(3):585-603.
   doi
3. Sugarbaker PH. National Organization for Rare Disorders (NORD): Pseudomyxoma peritonei [Internet]. Danbury (CT): National Organization for Rare Disorders. 1991 [updated Mar 22, 2012]. Available from https://www.rarediseases.org/rare-disease-information/rare-diseases/byID/843/viewFullReport.
4. Abdu B, Hobgood D, Stallings S, Depasquale S. Incidental finding of pseudomyxoma peritonei at primary cesarean section. Am J Perinatol. 2009;26(9):633-635.
   doi pubmed
5. Weaver CH. Mucocele of the appendix with pseudomucinous degeneration. Am J Surg. 1937;36:523.
   doi
6. Ronnett BM, Kurman RJ, Zahn CM, Shmookler BM, Jablonski KA, Kass ME, Sugarbaker PH. Pseudomyxoma peritonei in women: a clinicopathologic analysis of 30 cases with emphasis on site of origin, prognosis, and relationship to ovarian mucinous tumors of low malignant potential. Hum Pathol. 1995;26(5):509-524.
   doi
7. Ronnett BM, Zahn CM, Kurman RJ, Kass ME, Sugarbaker PH, Shmookler BM. Disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis. A clinicopathologic analysis of 109 cases with emphasis on distinguishing pathologic features, site of origin, prognosis, and relationship to "pseudomyxoma peritonei". Am J Surg Pathol. 1995;19(12):1390-1408.
   doi pubmed
8. Young RH, Gilks CB, Scully RE. Mucinous tumors of the appendix associated with mucinous tumors of the ovary and pseudomyxoma peritonei. A clinicopathological analysis of 22 cases supporting an origin in the appendix. Am J Surg Pathol. 1991;15(5):415-429.
   doi pubmed
9. Ronnett BM, Seidman JD. Mucinous tumors arising in ovarian mature cystic teratomas: relationship to the clinical syndrome of pseudomyxoma peritonei. Am J Surg Pathol. 2003;27(5):650-657.
   doi
10. Amini A, Masoumi-Moghaddam S, Ehteda A, Morris DL. Secreted mucins in pseudomyxoma peritonei: pathophysiological significance and potential therapeutic prospects. Orphanet J Rare Dis. 2014;9:71.
    doi pubmed
11. Pandey A, Mishra AK. Pseudomyxoma peritonei: disseminated peritoneal adenomucinosis variant. BMJ Case Rep. 2011;2011.
12. Smeenk RM, Verwaal VJ, Zoetmulder FA. Pseudomyxoma peritonei. Cancer Treat Rev. 2007;33(2):138-145.
    doi pubmed
13. Sugarbaker PH. New standard of care for appendiceal epithelial neoplasms and pseudomyxoma peritonei syndrome? Lancet Oncol. 2006;7(1):69-76.
    doi
14. Sugarbaker PH, Ronnett BM, Archer A, Averbach AM, Bland R, Chang D, Dalton RR, et al. Pseudomyxoma peritonei syndrome. Adv Surg. 1996;30(233-280.
15. Esquivel J, Sugarbaker PH. Clinical presentation of the Pseudomyxoma peritonei syndrome. Br J Surg. 2000;87(10):1414-1418.
    doi pubmed
16. Dixit A, Robertson JH, Mudan SS, Akle C. Appendiceal mucocoeles and pseudomyxoma peritonei. World J Gastroenterol. 2007;13(16):2381-2384.
    doi pubmed
17. Carmignani CP, Sugarbaker TA, Bromley CM, Sugarbaker PH. Intraperitoneal cancer dissemination: mechanisms of the patterns of spread. Cancer Metastasis Rev. 2003;22(4):465-472.
    doi pubmed
18. Walensky RP, Venbrux AC, Prescott CA, Osterman FA, Jr. Pseudomyxoma peritonei. AJR Am J Roentgenol. 1996;167(2):471-474.
    doi pubmed
19. Khan S, Patel AG, Jurkovic D. Incidental ultrasound diagnosis of pseudomyxoma peritonei in an asymptomatic woman. Ultrasound Obstet Gynecol. 2002;19(4):410-412.
    doi pubmed
20. Koyama S, Tomimatsu T, Sawada K, Kanagawa T, Tsutsui T, Kimura T. Pseudomyxoma peritonei originating from colorectal cancer during pregnancy. J Obstet Gynaecol Res. 2011;37(3):254-258.
    doi pubmed
21. Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 4th rev ed. Philadelphia: Elsevier Mosby; 2011. p. 533-538.
22. Coakley F, Gould R, Laros RK Jr., Thiet M. University of California, San Francisco (UCSF): CT and MR pregnancy guidelines [Internet]. San Francisco (CA): Department of Radiology & Biomedical Imaging. 2015 [updated July 17, 2012]. Available from http://radiology.ucsf.edu/patient-care/patient-safety/ct-mri-pregnancy.
23. Haase E, Yoo D, Sugarbaker PH. Management of appendiceal pseudomyxoma peritonei diagnosed during pregnancy. World J Surg Oncol. 2009;7:48.
    doi pubmed
24. Bradley RF, Stewart JHt, Russell GB, Levine EA, Geisinger KR. Pseudomyxoma peritonei of appendiceal origin: a clinicopathologic analysis of 101 patients uniformly treated at a single institution, with literature review. Am J Surg Pathol. 2006;30(5):551-559.
    doi pubmed
25. Symonds DA, Vickery AL. Mucinous carcinoma of the colon and rectum. Cancer. 1976;37(4):1891-1900.
    doi
26. Buell-Gutbrod R, Gwin K. Pathologic diagnosis, origin, and natural history of pseudomyxoma peritonei. Am Soc Clin Oncol Educ Book. 2013:221-225.
    doi pubmed
27. Rubino MS, Abdel-Misih RZ, Bennett JJ, Petrelli NJ. Peritoneal surface malignancies and regional treatment: a review of the literature. Surg Oncol. 2012;21(2):87-94.
    doi pubmed
28. Vaira M, Cioppa T, G DEM, Bing C, D'Amico S, D'Alessandro M, Fiorentini G, et al. Management of pseudomyxoma peritonei by cytoreduction+HIPEC (hyperthermic intraperitoneal chemotherapy): results analysis of a twelve-year experience. In Vivo. 2009;23(4):639-644.
29. Butterworth SA, Panton ON, Klaassen DJ, Shah AM, McGregor GI. Morbidity and mortality associated with intraperitoneal chemotherapy for Pseudomyxoma peritonei. Am J Surg. 2002;183(5):529-532.
    doi
30. Carr NJ, Finch J, Ilesley IC, Chandrakumaran K, Mohamed F, Mirnezami A, Cecil T, et al. Pathology and prognosis in pseudomyxoma peritonei: a review of 274 cases. J Clin Pathol. 2012;65(10):919-923.
    doi pubmed

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Journal of Clinical Gynecology and Obstetrics is published by Elmer Press Inc.