Pseudomyxoma peritonei | |
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Computed tomographic scan of an abdomen showing pseudomyxoma peritonei with multiple peritoneal masses (arrow) with "scalloping effect" seen. | |
Specialty | Oncology |
Pseudomyxoma peritonei (PMP) is a clinical condition caused by cancerous cells (mucinous adenocarcinoma) that produce abundant mucin or gelatinous ascites. [1] The tumors cause fibrosis of tissues and impede digestion or organ function, and if left untreated, the tumors and mucin they produce will fill the abdominal cavity. This will result in compression of organs and will destroy the function of the colon, small intestine, stomach, or other organs.
Prognosis with treatment in many cases is optimistic, [2] but the disease is lethal if untreated, with death occurring via cachexia, bowel obstruction, or other types of complications.
This disease is most commonly caused by an appendiceal primary cancer (cancer of the appendix); mucinous tumors of the ovary have also been implicated, although in most cases ovarian involvement is favored to be a metastasis from an appendiceal or other gastrointestinal source. Disease is typically classified as low- or high-grade (with signet ring cells). When disease presents with low-grade histologic features the cancer rarely spreads through the lymphatic system or through the bloodstream.
Signs and symptoms of pseudomyxoma peritonei may include abdominal or pelvic pain and/or bloating, distension, digestive disorders, weight changes, increased girth, and infertility.[ citation needed ]
The primary tumor appears to arise from the MUC2-expressing goblet cells and most commonly from these cells in the appendix. The KRAS and p53 genes may be involved in the oncogenesis. It may be diagnosed with a range of conditions. While the majority of these cases are associated with appendiceal carcinomas, [3] other conditions may also be found, including disseminated peritoneal adenomucinosis (DPAM), peritoneal carcinomas, several mucinous tumors (mucinous adenocarcinoma, mucinous cystadenoma, and mucinous cystadenocarcinoma), as well as other disease states. [4] Other primary sites that have been reported include colon, rectum, stomach, gallbladder, bile ducts, small intestine, urinary bladder, lung, breast, fallopian tubes, and the pancreas.
This disease is often discovered during surgery for other conditions, e.g., hernia repair, following which an experienced pathologist can confirm the diagnosis. Advanced stages may present as tumors palpable on the abdomen or distention of the belly ("jelly belly" is sometimes used as a slang term for the condition).
Due to the rarity of this disease, it is important to obtain an accurate diagnosis so that appropriate treatment may be obtained from a gastrointestinal cancer surgeon. Diagnostic tests may include CT scans, examination of tissue samples obtained through laparoscopy, and the evaluation of tumor markers.
In most cases, a colonoscopy is unsuitable as a diagnostic tool, because, in most cases, appendix cancer invades the abdominal cavity but not the colon (however, spread inside the colon is occasionally reported). PET scans may be used to evaluate high-grade mucinous adenocarcinoma, but this test is not reliable for detecting low-grade tumors, because those do not take up the dye which shows up on scans. New MRI procedures are being developed for disease monitoring, but standard MRIs are not typically used as a diagnostic tool. Diagnosis is confirmed through pathology.[ citation needed ]
There is substantial debate regarding histopathologic classification of pseudomyxoma peritonei. [5] In 1995, Ronnett et al. [6] proposed separating pseudomyxoma peritonei cases into two diagnostic categories: adenoma (disseminated peritoneal adenomucinosis, DPAM) or carcinoma (peritoneal mucinous carcinomatosis, PMCA) with a third category reserved for cases with intermediate features. In this classification system, cases of DPAM were characterized by peritoneal lesions composed of abundant extracellular mucin containing scant simple to focally proliferative mucinous epithelium with little cytologic atypia or mitotic activity (in other words, most cells looked fairly normal and there was no evidence of mitosis which would indicate that cells were rapidly dividing), with or without an associated appendiceal mucinous adenoma. Cases of PMCA were characterized by peritoneal lesions composed of more abundant mucinous epithelium with the architectural and cytologic features of carcinoma (irregular cells, evidence that cells were rapidly dividing, and other criteria), with or without an associated primary mucinous adenocarcinoma. Bradley et al. (2007) [7] argued that continued use of non-malignant terms, i.e., adenoma, for those frequent cases with low-grade features (such as DPAM), is misleading because pseudomyxoma peritonei is a disease state that results from invasion of the abdominal cavity by cells with uncontrolled growth. Bradley states that an adenoma, by definition, is a tumor confined to the appendiceal mucosa with absolutely no evidence of invasion beyond the muscularis mucosae.
The term mucinous adenocarcinoma is used in different contexts depending on the reference material used by the pathologist for disease classification. For example, neoplasms characterized by high-grade features, invasive glands and or signet ring cells, are termed adenocarcinoma in pathology literature. [8] However, some pathologists (e.g., Odze and Goldblum, Surgical Pathology of the GI Tract, Liver, Biliary Tract and Pancreas, 2nd ed.) also use the term mucinous adenocarcinoma when referring to low-grade, well-differentiated tumors lacking high-grade features. Low-grade mucinous adenocarcinoma is used by the American Joint Committee on Cancer and World Health Organization and is nearly or completely synonymous with the DPAM designation. [9] For low-grade mucinous adenocarcinoma, disease may be designated as "benign" because tumors do not invade deeply into tissue and rarely metastasize to parenchyma of organs; this designation may be misleading and confusing to the layperson because pseudomyxoma peritonei is not a harmless condition, fatal if untreated. High-grade or poorly differentiated mucinous adenocarcinoma has a generally poorer prognosis, though surgical treatment with heated intra-peritoneal chemotherapy (HIPEC) is yielding promising outcomes (see surgical treatment).
Immunohistochemical features:
Treatment is variable, both due to its rarity and to its frequently slow-growing nature. Treatment ranges from watchful waiting to debulking and hyperthermic intraperitoneal chemotherapy (HIPEC, also called intraperitoneal hyperthermic chemotherapy, IPHC) with cytoreductive surgery. [11]
The standard of care for mucinous adenocarcinoma with clinical condition PMP [12] involves cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC), performed by surgical oncologists who specialize in treating PMP. Some surgeons also apply early post-operative intraperitonial chemotherapy (EPIC), adjunct to surgical cytoreduction and HIPEC. In situations where surgery is not required immediately, patients can be monitored via CT scans, tumor marker laboratory tests, and physical symptoms, to determine when, and if, surgery is warranted. Although some surgical procedures may be rather extensive, patients can and do recover from surgery, and the majority of these patients can and do live productive lives. [13]
In debulking, the surgeon attempts to remove as much tumor as possible. CRS or cytoreductive surgery involves surgical removal of the peritoneum and any adjacent organs which appear to have tumor seeding. Since the mucus tends to pool at the bottom of the abdominal cavity, it is common to remove the ovaries, fallopian tubes, uterus, and parts of the large intestine. Depending upon the spread of the tumor, other organs might be removed, including but not limited to the gallbladder, spleen, and portions of the small intestine and/or stomach. For organs that cannot be removed safely (like the liver), the surgeon strips off the tumor from the surface. [14]
Chemotherapy (typically utilising the chemotherapeutic agent Mitomycin C) may be infused directly into the abdominal cavity after cytoreductive surgery (surgery removing all visible disease to kill remaining microscopic cancerous tumors and free floating cells). The heated chemotherapy (HIPEC) is perfused throughout the abdominal cavity for an hour or two as the last step in the surgery, or ports are installed to allow circulation and/or drainage of the chemicals for one to five days after surgery, known as early postoperative intraperitoneal chemotherapy (EPIC). EPIC may be given in multiple cycles for several months after surgery. [15]
Systemic chemotherapy may be administered as additional or adjuvant treatment. Due to the increased availability of new chemotherapies developed for colorectal cancer patients, some patients have experienced stability in tumor growth with systemic chemotherapy. Systemic chemotherapy is generally reserved for patients with advanced disease, recurrent disease, or disease that has spread to the lymph nodes or distant sites.[ citation needed ]
This disease may recur following surgery and chemotherapy. Periodic post operative CT scans and tumor marker laboratory tests are used to monitor patients for disease progression.
The overall incidence was previously estimated at 0.5 to 1 cases per 100,000 people per year. [16] Recent research in Europe indicates that the previous estimate of 1-2 persons per million may be underestimating the actual rate by approximately half, with the real incidence being approximately 3.2 persons per million, and the prevalence being 22 persons per million. [17] It is slightly more common in women than men (male:female ratio of approximately 1:1.3, [18] [19] ), although the actual ratio is difficult to identify due to potential misdiagnoses and possibly inclusion bias in reported studies. The median age at presentation is typically about 50 years with a range of 20–25 years, but PMP may strike persons of any age. [20] [21]
The first case was described by Carl F. Rokitansky in 1842. Werth in 1884 coined the term pseudomyxoma peritonei, describing it in association with a mucinous ovarian tumor.
In 1901, Frankel described the first case associated with a cyst of the appendix.
Audrey Hepburn died of pseudomyxoma peritonei in 1993.
A Krukenberg tumor refers to a malignancy in the ovary that metastasized from a primary site, classically the gastrointestinal tract, although it can arise in other tissues such as the breast. Gastric adenocarcinoma, especially at the pylorus, is the most common source. Krukenberg tumors are often found in both ovaries, consistent with its metastatic nature.
Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different cell types including epithelial cells, germ cells, and stromal cells. When these cells become abnormal, they have the ability to divide and form tumors. These cells can also invade or spread to other parts of the body. When this process begins, there may be no or only vague symptoms. Symptoms become more noticeable as the cancer progresses. These symptoms may include bloating, vaginal bleeding, pelvic pain, abdominal swelling, constipation, and loss of appetite, among others. Common areas to which the cancer may spread include the lining of the abdomen, lymph nodes, lungs, and liver.
Surface epithelial-stromal tumors are a class of ovarian neoplasms that may be benign or malignant. Neoplasms in this group are thought to be derived from the ovarian surface epithelium or from ectopic endometrial or fallopian tube (tubal) tissue. Tumors of this type are also called ovarian adenocarcinoma. This group of tumors accounts for 90% to 95% of all cases of ovarian cancer; however is mainly only found in postmenopausal women with the exception of the United States where 7% of cases occur in women under the age of 40. Serum CA-125 is often elevated but is only 50% accurate so it is not a useful tumor marker to assess the progress of treatment. 75% of women with epithelial ovarian cancer are found within the advanced-stages; however younger patients are more likely to have better prognoses than older patients.
Desmoplastic small-round-cell tumor (DSRCT) is an aggressive and rare cancer that primarily occurs as masses in the abdomen. Other areas affected may include the lymph nodes, the lining of the abdomen, diaphragm, spleen, liver, chest wall, skull, spinal cord, large intestine, small intestine, bladder, brain, lungs, testicles, ovaries, and the pelvis. Reported sites of metastatic spread include the liver, lungs, lymph nodes, brain, skull, and bones. It is characterized by the EWS-WT1 fusion protein.
Appendix cancer, also known as appendiceal cancer, is a very rare malignant tumor that forms in the vermiform appendix.
Omental cake is a radiologic sign indicative of an abnormally thickened greater omentum. It refers to infiltration of the normal omental structure by other types of soft-tissue or chronic inflammation resulting in a thickened, or cake-like appearance.
Carcinosis, or carcinomatosis, is disseminated cancer, forms of metastasis, whether used generally or in specific patterns of spread.
An immature teratoma is a teratoma that contains anaplastic immature elements, and is often synonymous with malignant teratoma. A teratoma is a tumor of germ cell origin, containing tissues from more than one germ cell line, It can be ovarian or testicular in its origin. and are almost always benign. An immature teratoma is thus a very rare tumor, representing 1% of all teratomas, 1% of all ovarian cancers, and 35.6% of malignant ovarian germ cell tumors. It displays a specific age of incidence, occurring most frequently in the first two decades of life and almost never after menopause. Unlike a mature cystic teratoma, an immature teratoma contains immature or embryonic structures. It can coexist with mature cystic teratomas and can constitute of a combination of both adult and embryonic tissue. The most common symptoms noted are abdominal distension and masses. Prognosis and treatment options vary and largely depend on grade, stage and karyotype of the tumor itself.
A mucinous neoplasm is an abnormal and excessive growth of tissue (neoplasia) with associated mucin. It arises from epithelial cells that line certain internal organs and skin, and produce mucin. A malignant mucinous neoplasm is called a mucinous carcinoma. For example, for ovarian mucinous tumors, approximately 75% are benign, 10% are borderline and 15% are malignant.
Primary fallopian tube cancer (PFTC), also known as tubal cancer, is a malignant neoplasm that originates from the fallopian tube. Along with primary ovarian and peritoneal carcinomas, it is grouped under epithelial ovarian cancers; cancers of the ovary that originate from a fallopian tube precursor.
Mucinous cystadenoma is a benign cystic tumor lined by a mucinous epithelium. It is a type of cystic adenoma (cystadenoma).
Peritoneal mesothelioma is the name given to the cancer that attacks the lining of the abdomen. This type of cancer affects the lining that protects the contents of the abdomen and which also provides a lubricating fluid to enable the organs to move and work properly.
Hyperthermic intraperitoneal chemotherapy (HIPEC) is a type of hyperthermia therapy used in combination with surgery in the treatment of advanced abdominal cancers. In this procedure, warmed anti-cancer medications are infused and circulated in the peritoneal cavity (abdomen) for a short period of time. The chemotherapeutic agents generally infused during IPHC are mitomycin-C and cisplatin.
Hyperthermic intrathoracic chemotherapy (HITOC) is part of a surgical strategy employed in the treatment of various pleural malignancies. The pleura in this situation could be considered to include the surface linings of the chest wall, lungs, mediastinum, and diaphragm. HITOC is the chest counterpart of HIPEC. Traditionally used in the treatment of malignant mesothelioma, a primary malignancy of the pleura, this modality has recently been evaluated in the treatment of secondary pleural malignancies.
Cytoreductive surgery (CRS) is a surgical procedure that aims to reduce the amount of cancer cells in the abdominal cavity for patients with tumors that have spread intraabdominally. It is often used to treat ovarian cancer but can also be used for other abdominal malignancies.
Paul Hendrick Sugarbaker is an American surgeon at the Washington Cancer Institute. He is known for developments in surgical oncology of the abdomen, including cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy, or HIPEC, a treatment alternately referred to as the Sugarbaker Procedure.
Ovarian germ cell tumors (OGCTs) are heterogeneous tumors that are derived from the primitive germ cells of the embryonic gonad, which accounts for about 2.6% of all ovarian malignancies. There are four main types of OGCTs, namely dysgerminomas, yolk sac tumor, teratoma, and choriocarcinoma.
Andrea A. Hayes Dixon is an American surgeon. She was the first pediatric surgeon to perform a high-risk, life-saving procedure in children with a rare form of cancer and developed the first orthotropic xenograft model of metastatic Ewing's sarcoma. In 2002, she became the first African American female pediatric surgeon board-certified in the United States.
Somashekhar SP is an Indian robotic surgeon, author and chairman of medical advisory board at Aster DM Healthcare - GCC & India. He is also the global director of Aster International Institute of Oncology in GCC & India. He is the president of the Association of Breast Surgeons of India, editor in chief of the IJGO Springer Indian Journal of Gynec Oncology and council member of The Association of Surgeons of India. He is also the editor of Annals of Breast Diseases.
Ovarian squamous cell carcinoma (oSCC) or squamous ovarian carcinoma (SOC) is a rare tumor that accounts for 1% of ovarian cancers. Included in the World Health Organization's classification of ovarian cancer, it mainly affects women above 45 years of age. Survival depends on how advanced the disease is and how different or similar the individual cancer cells are.