Initial Workup for Splenomegaly of Unknown Etiology

Confirming Splenomegaly

Abdominal ultrasound is the first-line imaging modality to confirm splenomegaly and assess for focal lesions, hepatomegaly, and lymphadenopathy 1
Spleen size 11-13cm represents mild splenomegaly, while >13cm is clinically significant and warrants aggressive workup 1, 2
Physical examination should document exact spleen size below the costal margin with careful percussion and palpation, measuring liver span at the mid-clavicular line 1

Complete blood count with differential to identify cytopenias, leukocytosis, lymphocytosis, or abnormal cell populations suggesting hematologic malignancy 1, 2
Peripheral blood smear review is critical to identify blasts, atypical lymphocytes, or other abnormal cells suggestive of leukemia or lymphoma 1, 2
Comprehensive metabolic panel to assess liver function, as liver disease is one of the three most common causes of splenomegaly in the United States 1
Lactate dehydrogenase (LDH) to screen for hemolysis or malignancy 1

Test for EBV, CMV, HIV, and hepatitis viruses as infectious causes are among the top three etiologies in developed countries 1

Flow cytometry of peripheral blood for immunophenotyping should be performed immediately if lymphoproliferative disorder is suspected based on CBC findings 1, 2
Testing for JAK2, CALR, and MPL mutations if myeloproliferative neoplasm is suspected (particularly with leukocytosis, thrombocytosis, or unexplained splenomegaly) 1, 2
Bone marrow aspiration and biopsy is indicated when abnormal cells are found in peripheral blood, unexplained cytopenias are present, or myeloproliferative or lymphoproliferative disorder is suspected 1, 2

CT or MRI of the abdomen should be obtained if ultrasound findings are equivocal, lymphadenopathy needs characterization, or focal splenic lesions are present 1
Imaging should evaluate for hepatomegaly, lymphadenopathy, and focal splenic lesions that may require tissue diagnosis 1

Do not delay bone marrow evaluation in patients with concerning peripheral blood findings (blasts, significant cytopenias, or abnormal cell populations) 1
Do not miss lymphoma-associated HLH: approximately 40-70% of adult HLH cases are malignancy-associated, particularly with Hodgkin lymphoma, diffuse large B-cell lymphoma, and T-cell lymphomas 3
Consider PET-guided imaging and repetitive tissue sampling if lymphoma is suspected but initial biopsies are negative, as tumor-infiltrating reactive lymphocytes can mask underlying lymphoma 3

Immediate hematology referral is warranted for peripheral smear showing blasts or abnormal lymphocytes beyond typical reactive changes, presence of cytopenias, or symptomatic splenomegaly without clear etiology after initial workup 1, 4

The American Association for the Study of Liver Diseases recommends a comprehensive metabolic panel, including liver function tests, as it is essential since liver disease is one of the three most common causes of splenomegaly in the United States 5
The American Association for the Study of Liver Diseases suggests that platelet count should be included as part of the CBC, as it helps calculate fibrosis indices that can detect advanced fibrosis and portal hypertension 5

The National Comprehensive Cancer Network recommends a disseminated intravascular coagulation panel, including D-dimer, fibrinogen, PT, and PTT, in acute presentations, particularly in acute leukemia 6
The National Comprehensive Cancer Network suggests that a tumor lysis syndrome panel, including uric acid, potassium, phosphates, and calcium, is indicated when malignancy is suspected 6

The British Society of Gastroenterology advises against assuming alcoholic liver disease in patients with alcohol use, and recommends that other causes must be excluded through appropriate testing 7

The American Association for the Study of Liver Diseases recommends performing careful percussion and palpation of the entire liver and spleen with measurement of the liver span at the mid-clavicular line, and assessing for hepatomegaly, which has a sensitivity of 60% and specificity of 44% for detecting advanced liver disease, while splenomegaly has a sensitivity of 93% and specificity of 57% 5