Abdominal mass resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: , Javaria Anwer M.D.[2]
Synonyms and keywords: abdominal lump resident survival guide

Overview

An abdominal mass is a vast entity in oncology.

Causes

Life Threatening Causes

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated. The life-threatening causes of an abdominal mass include:

• Abdominal aortic aneurysm, specifically ruptured abdominal aortic aneurysm.
  • Tenth most common cause of death in the Western world.
  • Total mortality is estimated to be 80–90 %.
  • The 2013 mortality rate of US population above 44 years of age was 2.5 per 100,000. The incidence is on the decrease for the past two decades after a plateau. (the mortality rates act as a surrogate of incidence).
• Volvulus

Common Causes

Common causes of an abdominal mass described below follow a descending order. The list is based on a retrospective study from Turkey among 45 adult patients who underwent surgery because of an intra-abdominal mass (between May 2010 and May 2017).

Benign pathologies

• Mesenteric cyst
• Endometriosis
• Hydatid cyst
• Fibroma
• Dystrophic calcification
• Aberrant pancreas
• Leiomyoma
• Pseudocyst

Malignant pathologies

• Gastrointestinal stromal tumor (GIST)
• Liposarcoma
• Ovarian tumor
• Chondrosarcoma
• Neuroendocrine tumor
• Malignt mesenchymal tumor
• Lymphoma
• Schwannoma
• The following chart illustrates the probable causes of an abdominal mass based on the location and salient features.

Causes of abdominal mass

Abdominal wall mass ❑ Primary tumors (WHO classification) ❑ Adipocytic tumors (lipoma, liposarcoma) ❑ Fibroblastic/myofibroblastic tumors (desmoid tumor) ❑ Nerve sheath tumors (schwannoma, neurofibroma) ❑ Hemangiomas ❑ Undifferentiated pleomorphic sarcomas ❑ Metastasis ❑ Tumor-like mass ❑ Endometriosis, abscess, hematoma ❑ Hernias (epigastric, umbilical, incisional, and spigelian)

Intra-abdominal/ retroperitoneal mass

Hepatic mass ❑ Hepatitis (infectious, DILI, alcoholic, NASH, autoimmune, Wilson's disease ❑ Storage diseases (glycogen storage disease, lysosomal storage disease, lipid storage disease, hemochromatosis) ❑ Tumors ❑ Primary Benign:adenoma, FNH ❑ Primary malignant:HCC, cholangiocarcinoma ❑ Metastatic: Hemangioma, lymphoma, myeloma and solid tumors. ❑ Cholestasis (PBC, PSC)

Splenic mass ❑ Infectious (IM, liver abscess, echinococcosis) ❑ Myeloproliferative (lymphomas and leukemias) ❑ Storage (Gaucher's, Niemann-Pick disease) ❑ Infiltrative:amyloidosis, sarcoidosis ❑ Miscellineous (PH, metastases (lung cancer or breast cancer, Felty's syndrome)

Gastrointestinal and Genitourinary mass ❑ Gastrointestinal ❑ Volvulus ❑ IBD ❑ Colon cancer ❑ Gastric cancer ❑ Cholecystitis ❑ Genitourinary system ❑ Bladder distension ❑ Ovarian cyst/ ovarian cancer ❑ Leiomyoma ❑ Ureteropelvic junction obstruction/ urinomas ❑ Testicular cancer

Pancreatic mass ❑ Pancreatic cyst ❑ Neoplastic (mucinous, serous, intraductal papillary, and solid pseudopapillary) ❑ Non-neoplastic (true, mucinous) ❑ Inflammatory (pseudocyst, acute fluid collection) ❑ Solid: ❑ Adenocarcinomas (ductal, bile duct, ampullar and duodenal) ❑ Pancreatic neuroendocrine tumors ❑ Others (lymphoma and metastasis)

Retroperitoneal mass (majority tumors are malignant)

Neoplastic ❑ Solid ❑ Lymphoma ❑ Hydronephrosis ❑ Leiomyosarcoma ❑ Germ cell tumors ❑ Liposarcoma/ sarcoma ❑ Renal cell carcinoma ❑ Abdominal Aortic Aneurysm(AAA) ❑ Cystic ❑ Cystadenoma/ cystadenocarcinoma ❑ Mature teratoma

Non-neoplastic ❑ Solid ❑ Extramedullary hematopoiesis ❑ Retroperitoneal fibrosis ❑ Erdheim-Chester disease ❑ Cystic ❑ Epidermoid cyst ❑ Non-pancreatic pseudocyst ❑ Lymphoceles, hematoma ❑ Bronchogenic cyst

Diagnosis

Shown below is an algorithm summarizing the diagnosis and management of a pulsatile abdominal mass.

Pulsatile abdominal mass ❑ History (such as associated pain, past medical, surgical history) ❑ Physical exam (such as location and extent of the mass, change in size) ❑ Risk factors for the development of Abdominal Aortic Aneurysm (AAA)

Assess hemodynamic stability

Unsable

Stable

❑ Airway, Breathing and Circulation (ABC) ❑ Clinical diagnosis of ruptured AAA considered if patient is/was a smoker, >60 years old, HTN history, an existing diagnosis of AAA, and abdominal/back pain. ❑ Immediate bedside aortic US ❑ Systolic BP >70 acceptable (permissive hypotension)

❑ Abdominal ultrasound scan (US) ❑ Abdominal US (100% Sn and Sp but visualization among 1-3% patients) ❑ CTA (after normal RFTs) serves as first line modality but gold standard to assess AAA in few cases

Emergency repair (open or endovascular) if expertise are available

Transfer to a facility with vascular specialist expertise

AAA not demonstrated

AAA demonstrated

Look for other possible causes on a CT scan ❑ Heart failure (hepatomegaly, portal hypertension, pulmonary edema, and contrast reflux into IVC and hepatic veins) ❑ Colonic diverticula with peri-colic inflammation and fluid collection ❑ Dilatation of renal pelvicalyceal systems, splenomegaly ❑ Tumors (distinct mass or diffuse organ infiltration, LAD, metastasis to other organs) ❑ Pancreatic pseudocyst (Large cyst/multiple cysts in and around the pancreas with calcifications maybe, splenic vein thrombosis, and pseudoaneurysms of splenic artery, bleeding into a pseudocyst

<5.5cm

≥5.5cm

No pain demonstrated Rupture risk < operative repair risk (1 year)

Pain is present Search for risk factors: female, smoker, height, age, HTN history or other causes

No Pain demonstrated Rupture risk > operative repair risk (1 year)

Pain is present High rupture risk

Other causes (low rupture risk)

No other causes (moderate-high risk of rupture)

Elective repair is considered

❑ RFTs ❑ Crt<2mg/dl=CTA ❑ Crt>2mg/dl or dye allergy=MRA

❑ Follow-up in 6M ❑ Repair of aneurysm if it grows >0.4cm/year or becomes symptomatic ❑ Patient education

❑ Unruptured AAA (moderate risk) ❑ Hyperattenuating crescent sign, >150% normal diameter of aorta, mural thrombus and calcification ❑ Consider elective repair

❑ Ruptured AAA ❑ Contrast extravasation, draped aorta sign, and retroperitoneal hematoma with perirenal and pararenal space extension. ❑ Emergency repair

Treatment

Shown below is an algorithm summarizing the treatment of abdominal mass according the the [...] guidelines.

Do's

• Start the assessment of a patient with an abdominal mass using the pneumonic "ABC:" airway, breathing and circulation, to identify an unstable patient.
• Taking careful history, and thorough physical examination are crucial to creating narrow differential diagnoses.
• Among females of childbearing age (average age 12 and 51 or start of menstrual cycle till menopause), pregnancy screening (usually a urine pregnancy test) should be performed before diagnostic radiation exposure or interventions such as fluoroscopy‐guided interventions.
• Order an ultrasound or MRI among pregnant females to avoid exposure to radiation.
• Perform a pelvic and testicular examination among patients with lower abdominal pain.
• Correlate the CD4 count in HIV positive patients with the most commonly occurring pathology.
• Abdominal aortic aneurysm and malignancy are more important considerations among patients above 50 years of age than for younger patients.
• Suspect ruptured abdominal aortic aneurysm in old patients presenting with a pulsating mass, associated abdominal pain and a history of tobacco use.
• CT angiography is the gold standard and imaging modality of choice for the evaluation of abdominal aortic aneurysm.

Don'ts

• The content in this section is in bullet points.

References

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