Metastatic spread of malignant tumors into the peritoneum, a two-layered (parietal and visceral) mesothelial lining, is almost universally fatal within a short period of time, as only palliative therapeutic measures may be implemented at this stage of progression [1] [2] [3] [4] [5]. Neoplasms of the gastrointestinal system (particularly colorectal cancer) and the genitourinary tract, as well as hepatic, pancreatic, and primary peritoneal tumors (mesothelioma), are known for their propensity to metastasize into this anatomical landmark, and they are able to do so in several ways [1] [2] [4] [6]. Proximal masses (eg. gastrointestinal or ovarian cancers) are able to directly penetrate into the peritoneum, whereas spread via the lymphatic or hematogenous routes (typical for more distant primary malignancies, such as melanoma, lung cancer, or breast cancer), as well as intraperitoneal dissemination of the tumor through ascitic fluid (a potential complication during surgical procedures), are other possible routes [1] [2] [6]. The clinical presentation of peritoneal metastasis is quite variable, and often depends on the location and the severity of tumor invasion, but in most cases, the initial course is asymptomatic [2]. The majority of patients, however, develop symptoms of abdominal pain, distension, and discomfort (developing as a result of bowel obstruction), followed by weight loss, nausea, vomiting, and severe fatigue with cachexia [1] [2] [4].

• Weight Loss

  The clinical presentation is initially asymptomatic, but at some point, complaints of abdominal pain, weight loss, and ascites appear. [symptoma.com]

  We report an unusual presentation of chronic appendicitis with a synchronous peritoneal nodule on CT in a 76-year-old woman who presented with poor appetite, weight loss and a mass in the right iliac fossa. [ncbi.nlm.nih.gov]

  Symptoms and Diagnosis The symptoms of local spread of bowel cancer can be vague, but are likely to include unexplained pain, tenderness over the area, or unusual discharges, changed appetite or unexpected weight loss. [bowelcanceraustralia.org]

  Presents with abdominal pain and distension, fever, night sweats, weight loss, and altered bowel habits. Ascites is present in about half of cases. Abdominal mass may be felt in a third of cases. [wikidoc.org]

• High Fever

  During CCRT, she suffered from acute lower abdominal pain, high fever, and leukocytosis. [ncbi.nlm.nih.gov]

• Abdominal Pain

  The clinical presentation is initially asymptomatic, but at some point, complaints of abdominal pain, weight loss, and ascites appear. [symptoma.com]

  During CCRT, she suffered from acute lower abdominal pain, high fever, and leukocytosis. [ncbi.nlm.nih.gov]

• Constipation

  Gastrointestinal symptoms (nausea/vomiting, constipation, diarrhoea, anorexia) remained stable under PIPAC therapy. [ncbi.nlm.nih.gov]

  The beginning symptoms of peritoneal mesothelioma include abdominal distension, abdominal pain, swelling or tenderness around the abdomen and constipation or diarrhea. [asbestos.com]

  Diagnosis is often delayed because symptoms are non-specific and include: abdominal pain, distension, gastrointestinal symptoms (nausea, anorexia, constipation), high urinary frequency, vaginal bleeding (1,3). [medichub.ro]

  Symptoms of peritoneal carcinomatosis may include the following: [4] Abdominal distension Nausea Bloating Intermittent abdominal pain Vomiting Alternating diarrhea and constipation Physical Examination Patients with peritoneal carcinomatosis usually appear [wikidoc.org]

• Abdominal Mass

  The abdominal mass was 26 x 17 x 12 cm in size, as determined by magnetic resonance imaging, and was diagnosed as a peritoneal relapse of GIST. Treatment with 400 mg of imatinib daily was started. [ncbi.nlm.nih.gov]

  Peritoneal inclusion cyst in a man extending into the upper abdomen Peritoneal inclusion cyst (4) On the left images of a male patient, who presented with a lower abdominal mass. [radiologyassistant.nl]

  Abdominal mass may be felt in a third of cases. The peritoneal fluid is characterized by a protein concentration 3 g/dL with 1.1 g/dL SAAG and lymphocyte predominance of WBC. Definitive diagnosis in 80% of cases is by culture. [wikidoc.org]

• Increased Abdominal Girth

  On the left a 33-year-old man who complains of an increasing abdominal girth, abdominal fullness, and a palpable abdominal mass. First study the images on the left and continue with the MR. [radiologyassistant.nl]

  Patients most often present with abdominal pain and later increased abdominal girth and ascites along with anorexia, weight loss and abdominal pain. Mean time from diagnosis to death is less than 1 year without treatment. [wikidoc.org]

• Pelvic Mass

  We present a case of a 36-year-old woman with cough, hemoptysis, dyspnea with detection of lung mass, and incidental detection of pelvic mass. Fine needle aspiration cytology failed to reveal the true nature of both the lesions. [ncbi.nlm.nih.gov]

  The imaging features of a peritoneal inclusion cyst are non-specific except that it has to be located in the pelvis: Multicystic pelvic mass Enhancing septa Peritoneal surfaces of uterus, bladder May extend into upper abdomen On the left a transvaginal [radiologyassistant.nl]

• Anger

  Angers, France. 33 Department of Surgical Oncology, Institut de Cancérologie de Lorraine, Vandoeuvre-lès-Nancy, France. 34 Department of Surgical Oncology, Institut Curie, Paris, France. 35 Department of Surgical Oncology, Centre Léon Bérard, Lyon, [ncbi.nlm.nih.gov]

• Communicating Hydrocephalus

  Serial imaging studies including enhanced CT and MRI were performed at the first admission, during which the patient was diagnosed with a non-malignant communicating hydrocephalus. [ncbi.nlm.nih.gov]

The clinical manifestation of peritoneal metastasis is nonspecific, but the observation of a newly formed ascites must raise suspicion toward a malignant etiology [2]. For this reason, the physician must obtain a detailed patient history that will assess the duration of symptoms, their onset, as well as progression, whereas anamnestic data of malignant diseases is crucial for making a presumptive diagnosis. In fact, up to 50% of gastric cancers and 10-35% of colorectal cancers recur as peritoneal metastasis [3]. After a thorough physical examination, imaging studies need to be employed. Abdominal ultrasonography, a common first-line procedure, provides little benefit when it comes to visualizing the metastatic deposits, but its use as a guide to obtain a viable sample of the ascitic fluid or of superficial tumors for histopathological testing is invaluable [6]. Instead, more advanced methods - computed tomography and magnetic resonance imaging are the cornerstones for identifying peritoneal metastasis and tumor spread [2] [3] [6] [7]. Typical findings range from multifocal nodules to aggressive infiltrating masses, whereas stellate lesions and calcifications might also be encountered [2] [7]. MRI is particularly effective if used with gadolinium as a contrast, and images should be obtained 5-10 minutes after the agent is administered [2]. The diagnosis can be further solidified through the use of fluorodeoxyglucose (FDG)-PET [2].

1. Bellavance EC, Alexander HR Jr. Palliative interventions in patients with peritoneal metastases and malignant bowel obstruction. J Clin Oncol. 2012;30(35):4290-4201.
2. Levy AD, Shaw JC, Sobin LH. Secondary tumors and tumorlike lesions of the peritoneal cavity: imaging features with pathologic correlation. Radiographics. 2009;29(2):347-373.
3. Coccolini F, Gheza F, Lotti M, et al. Peritoneal carcinomatosis. World J Gastroenterol. 2013;19(41):6979-6994.
4. Klaver YL, Lemmens VE, Nienhuijs SW, Luyer MD, de Hingh IH. Peritoneal carcinomatosis of colorectal origin: Incidence, prognosis and treatment options. World J Gastroenterol. 2012;18(39):5489-5494.
5. Raptopoulos V, Gourtsoyiannis N. Peritoneal carcinomatosis. Eur Radiol. 2001;11(11):2195-206.
6. Healy JC. Detection of peritoneal metastases. Cancer Imaging. 2001;1(2):4-12.
7. Agarwal A, Yeh BM, Breiman RS, Qayyum A, Coakley FV. Peritoneal calcification: causes and distinguishing features on CT. AJR Am J Roentgenol. 2004;182(2):441-445.