Pseudomyxoma peritonei differential diagnosis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nima Nasiri, M.D.[2]

Overview

Pseudomyxoma peritonei must be differentiated from peritoneal carcinomatosis without mucinous ascites, peritoneal sarcomatosis, and tuberculosis peritonitis.

Differential Diagnosis

Differentiating pseudomyxoma peritonei from other diseases

• On the basis of findings on CT scan such as visceral scalloping and histopathology, pseudomyxoma peritonei must be differentiated from other similar rare diseases such as peritoneal carcinomatosis without muscinous ascites, tuberculosis peritonitis, sarcomatosis peritonei.

Diseases	Clinical manifestations			Para-clinical findings				Gold standard	Additional findings
	Symptoms		Signs
				Lab Findings	Imaging		Histopathology
	Symptom	Constitutional symptoms	Physical exam	Other lab values	CT Scan	Ultrasound
Pseudomyxoma peritonei	Bloating Abdominal distention	–	Abdominal tenderness	Non specific	Low-attenuation Scalloping of the visceral surfaces differentiates pseudomyxoma from other causes of peritonitis. Typically does not invade visceral organs or spread by lymphatic or hematogenous routes unlike mucinous carcinomatosis	The echoes within pseudomyxoma peritonei are not mobile. Echogenic septations within the gelatinous ascites. Scalloping of the hepatic and splenic margins	Depending on WHO classification, whether it's low or high grade with cellular atypia or acellular mucin. ( DPAM, PMCA) Gelatinous ascites in peritoneum and visceral organs,usually underneath the right hemidiaphragm, liver. Omental cake	Diagnostic laparoscopy/laparotomy	Immunohistochemistry CK 20 CDX2 MUC2 MUC5AC
Peritoneal carcinomatosis without mucinous ascites	Abdominal pain Abdominal distention	–	Abdominal distention Abdominal tenderness	Positive cytology indicating malignant ascites on paracentesis.	Pleural effusion and/or masses in chest Mesenteric or retroperitoneal lymphadenopathy Omental caking, and invasion into parenchymal organs	Echoes are mobile No scalloping of visceral organs.	Depending on primary tumor origin ( colorectal,ovary, appendix)	Laparoscopy/laparotomy tissue sampling	Immunohistochemistry CEA CA 19-9 CDX2 MUC2 MUC5AC
Peritoneal sarcomatosis	Abdominal pain Abdominal distention Bloating Nausea	–	Abdominal mass	Neutrophilia Reduced hemoglobin Lymphopenia Thrombocytosis	Heterogeneous bulky masses Hypervascularity with or without hemoperitoneum Variable presence of ascites.	Hyperechogenic mass Little ascites	Soft-tissue implants along the peritoneum Dense fibrotic sarcoma mass	CT-guided percutaneous tissue biopsy	Associated conditions: Sarcoma gastrointestinal stromal tumors (GISTs) Liposarcomas, Leiomyosarcomas.
Lymphomatosis	Abdominal pain Bloating Swollen lymph node	+	Splenomegaly Lymphadenopathy Abdominal mass Abdominal tenderness	Anemia Pancytopenia Thrombocytopenia Thrombocytosis	Omental cake Aneurysmal dilatation of the bowel loop with wall thickening. Enlarged supraclavicular, mediastinal and para-aortic lymph nodes.	Large ascitic fluid	Atypical lymphoid cells	Biopsy and histology	Rare manifestation of lymphoma, seen most frequently with non-Hodgkin lymphoma Associated with Herpes virus 8 (HHV-8), which is also associated with Kaposi sarcoma, and Epstein-Barr virus Immunohistochemistry: CD20 CD79a CD10
Tuberculosis Peritonitis	Abdominal pain	+	Abdominal tenderness Abdominal mass or bulging of flanks	A positive tuberculin skin test Ascitic fluid will have an elevated white blood cell count with a lymphocytic predominance	Miliary microabscesses in the liver or spleen lymph node calcification Inflammatory thickening of the terminal ileum and cecum low-attenuation lymphadenopathy	Ascites/loculated fluid Adnexal mass Peritoneal thickening Omental thickening	Caseating granuloma with central area of necrotic acellular debris surrounded by histiocytes	Laparoscopy and peritoneal biopsy	Immunohistochemistry Elevated serum CA-125 level Normal serum CA 19-9, and CEA associated with lymphocyte predominant benign ascites
Endometriosis	Menstrual cramps Painful bowel movements Painful urination during menstrual periods Heavy menstrual periods Pain during or after sex	–	Immobile uterine Cervical motion tenderness Fixed and retroverted uterus Tender adnexal mass Tender uterosacral nodularity	Thomsen-Friedenreich (T) antigen (Gal beta1-3GalNAc)	CT Scan is not routinely used for diagnosing endometriosis.	Hypoechogenic linear thickening or nodules/masses	Endometrial-type glands and stroma Hemosiderin-laden macrophages Hemorrhagic, reddish brown nodules on the surfaces of peritoneum.	Visual inspection with laparascopy	Associated conditions: Increased risk of breast cancer Non-Hodgkin's lymphoma Chronic pelvic pain
Sclerosing encapsulating peritonitis	Fever Weight loss Loss of appetite Altered bowel movement Abdominal pain	–	Abdominal mass Abdominal tenderness	Increased CRP level Fibrin-fibrin degradation product Occult blood	Diffusely thickened peritoneum and ascites Small bowel may be matted within loculated fluid collections Encapsulated small bowel	Thin echogenic strands can be seen within ascitic fluid Tethered small bowel	Dense,opaque peritoneum Progressive collagen formation with an associated chronic inflammatory infiltrate	Histology	Most commonly in patients who undergo continuous ambulatory peritoneal dialysis. It may also be idiopathic, associated with ventriculoperitoneal shunts, liver transplantation
Gliomatosis Peritonei	Abdominal pain Bloating Nausea Vomiting Constipation	–	Abdominal tenderness	SOX2+/OCT4-/NANOG- immunophenotype	Soft-tissue peritoneal nodules and masses, Omental caking and ascites Adnexal or pelvic mass	Cystic-solid pelvic mass	Mature glial tissue in the peritoneal cavity Micronodular growth pattern Multiple small peritoneal implants	Diagnostic laparoscopy and biopsy.	Associated conditions: Solid or immature ovarian teratomas Ventriculoperitoneal shunts Immunohistochemistry: S100 CK AE1/AE3 Glial fibrillary acidic protein (GFAP)
Osseous metaplasia	Abdominal pain Nausea Vomiting Bloating	–	Abdominal tenderness Abdominal distention	Reduced RBC Positive FOBT	High-attenuation, linear-branching spread along the mesentery, omentum and peritoneal surfaces.		Dystrophic calcification Benign, mature bone with lacunae. Focal “lace-like” osteoid Reactive myofibroblasts with hemorrhage and fat necrosis No tumor cell necrosis or atypical cells.	Biopsy and histology	Occurs after trauma or surgery The histologic differential diagnosis includes: Extraskeletal osteosarcoma
Splenosis	Increase in abdominal girth	–	Abdominal mass Abdominal tenderness Abdominal rigidity and guarding due to spleen rupture in some cases and retroperitoneal bleeding.	Absence of Howell-Jolly bodies.	Lobulated masses and nodules along diaphragm, and lower mediastinum of left side. Multiple calcified granulomas with fibrosis which mimic mesothelioma. Homogenous splenic tissue may be seen.		Lesions are typically multiple, small, reddish-brown nodules that range in size from a few millimeters to 7 cm	Biopsy and Histopathology	Pathogenesis: Mechanical implantation of splenic tissue after splenectomy or splenic rupture. Non-invasive diagnostic method of choice: Tc-99m-labeled heat-damaged RBC scan Liver splenosis can mimic hepatocellular carcinoma. Most common extraperitoneal site of splenosis is thoracic.
Melanosis	Majority of cases are asymptomatic Increase in abdominal girth	–	Abdominal distention in case of peritonitis,otherwise no findings.	Majority have normal lab values Positive FOBT reported in a case with colorectal polyp			Pigmentation within the dermoid, omentum, and peritoneal cavity Pigment-laden macrophages within the mucosa on PAS staining	Biopsy and histology	Associated diseases: Enteric duplication cyst Ovarian cystic teratomas Gastric triplication Immunohistochemistry: Positive for CD68 Negative melanin-A Negative HMB-45
Inflammatory Pseudotumor	Fever Weight loss Growth retardation Fatigue Symptoms related to mass effect	–	Abdominal distention Abdominal pain	Anemia Thrombocytosis Polyclonal hypergammaglobulinemia Stain positive for ALK with immunohistochemistry	CT findings are non specific ascites, masses may be seen in peritoneum,mimic neoplasm.		Loose myxoid areas with interspersed spindle cells, Variable vascularity Dense collagen, and dense spindled myofibroblasts mixed with inflammatory cells, include plasma cells and lymphocytes.	Biopsy and histology	Chromosomal translocations: ALK gene Immunochemistry: IgG4 positive plasma cell

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