 Discussion of Procedures by Variant Variant 1: Palpable abdominal mass. Suspected intra-abdominal neoplasm. Initial imaging. Little has been written about the use of imaging in evaluating palpable abdominal masses since the 1980s. Newer reviews and case reports have focused on evaluation of specific masses using CT, ultrasound (US), and MRI. Radiography of the abdomen and fluoroscopy play a limited role in the diagnosis and workup of a palpable intra-abdominal mass. CT Abdomen There have been no recent studies on the diagnostic yield of CT for abdominal masses; however, it is widely used and assumed to be accurate in patients presenting with varying pathologies that may cause an abdominal mass [4- 7]. Most data on diagnostic accuracy stem from studies that are >30 years old. In a controlled trial from 1981 by Dixon et al [8], CT established diagnosis more quickly and reduced inpatient workup times in patients with abdominal masses when compared against conventional radiography and workup. In another study from 1984 by Williams et al [9], CT demonstrated high positive predictive value (99%) and negative predictive value (97%) for determining the presence or absence of a mass and correctly identified the organ of origin in 93% of patients with palpable abnormalities on clinical examination. The Dixon et al [8] study demonstrated that, compared with strategies not using CT, the use of CT can result in savings in time for diagnosis. Accordingly, when US findings are indeterminate, CT imaging should be obtained in a timely manner. Organomegaly (ie, enlargement of the liver, spleen, or kidneys), may present with a palpable mass. The differential diagnosis is lengthy, including lymphoma, primary organ disease, metastatic disease, extramedullary hematopoiesis, granulomatous disease, and infections. CT can provide clues to help narrow the differential aPanel Vice-Chair, Mallinckrodt Institute of Radiology, Saint Louis, Missouri.
Palpable Abdominal Mass Suspected Neoplasm.  Discussion of Procedures by Variant Variant 1: Palpable abdominal mass. Suspected intra-abdominal neoplasm. Initial imaging. Little has been written about the use of imaging in evaluating palpable abdominal masses since the 1980s. Newer reviews and case reports have focused on evaluation of specific masses using CT, ultrasound (US), and MRI. Radiography of the abdomen and fluoroscopy play a limited role in the diagnosis and workup of a palpable intra-abdominal mass. CT Abdomen There have been no recent studies on the diagnostic yield of CT for abdominal masses; however, it is widely used and assumed to be accurate in patients presenting with varying pathologies that may cause an abdominal mass [4- 7]. Most data on diagnostic accuracy stem from studies that are >30 years old. In a controlled trial from 1981 by Dixon et al [8], CT established diagnosis more quickly and reduced inpatient workup times in patients with abdominal masses when compared against conventional radiography and workup. In another study from 1984 by Williams et al [9], CT demonstrated high positive predictive value (99%) and negative predictive value (97%) for determining the presence or absence of a mass and correctly identified the organ of origin in 93% of patients with palpable abnormalities on clinical examination. The Dixon et al [8] study demonstrated that, compared with strategies not using CT, the use of CT can result in savings in time for diagnosis. Accordingly, when US findings are indeterminate, CT imaging should be obtained in a timely manner. Organomegaly (ie, enlargement of the liver, spleen, or kidneys), may present with a palpable mass. The differential diagnosis is lengthy, including lymphoma, primary organ disease, metastatic disease, extramedullary hematopoiesis, granulomatous disease, and infections. CT can provide clues to help narrow the differential aPanel Vice-Chair, Mallinckrodt Institute of Radiology, Saint Louis, Missouri.