eMedicine Specialties > Hematology > Immune System and Disorders

Splenomegaly: Differential Diagnoses & Workup

Author: David J Draper, MD, Hematology/Oncology Fellow, The University Hospital, Cincinnati, Ohio
Coauthor(s): Ronald A Sacher, MB, BCh, MD, FRCPC, Professor, Internal Medicine and Pathology, Director, Hoxworth Blood Center, University of Cincinnati Academic Health Center; Emmanuel N Dessypris, MD, Professor of Medicine, Medical College of Virginia; Chief, Medical Service, Hunter Holmes McGuire Department of Veterans Affairs Medical Center; Lewis J Kaplan, MD, FACS, FCCM, FCCP, Director, SICU and Surgical Critical Care Fellowship, Associate Professor, Department of Surgery, Section of Trauma, Surgical Critical Care, and Surgical Emergencies, Yale University School of Medicine
Contributor Information and Disclosures

Updated: Oct 4, 2009

Differential Diagnoses

Other Problems to Be Considered

Angioimmunoblastic lymphadenopathy
Banti disease
Congestive heart failure
Drug reactions with serum sickness syndromes
Gaucher disease
Histiocytosis X
Hyperlipidemias
Idiopathic splenomegaly
Immune hemolytic anemias
Leukocyte disorders
Lymphomas
Mucopolysaccharidosis
Niemann-Pick disease
Ovalocytosis
Splenic vein obstruction
Symptomatic human immunodeficiency virus (HIV) infection
Trypanosomiasis

Workup

Laboratory Studies

• Perform a complete blood cell (CBC) count with differential, platelet count, and peripheral blood smear in cases of splenomegaly.
• The term hypersplenism describes some of the sequelae that are often observed with splenomegaly. Criteria for a diagnosis of hypersplenism include anemia, leukopenia, thrombocytopenia, or combinations thereof, plus cellular bone marrow, splenomegaly, and improvement after splenectomy.
  • Anemia: The etiology of the anemia observed in splenomegaly is the result of sequestration and hemodilution.
  • Leukopenia: Increased destruction or sequestration of leukocytes causes the leukopenia observed in splenomegaly. Leukopenia is closely related to neutropenia. Neutropenia (absolute neutrophil count [ANC] <2000 × 10⁶/L) is the result of an increase in the marginated granulocyte pool, a portion of which is located in the spleen. Sequestration may also play a role in the genesis of neutropenia.
  • Thrombocytopenia: Approximately 30% of the total platelet mass exists as an exchangeable pool in the spleen. Increased splenic platelet pooling is the primary cause of the thrombocytopenia of hypersplenism. In patients with hypersplenism, as much as 90% of the total platelet mass can be found in the spleen. In hypersplenism, the platelet count is usually 50,000-150,000/µL.

Imaging Studies

• Craniocaudal measurement: A craniocaudal measurement of 11-13 cm is frequently used as the upper limit of normal for splenic size in imaging studies. However, because of wide variations in shape, no consistent correlation has been recognized between the spleen's length and its overall volume, as has been determined for other organs (eg, kidney).
• Computed tomography (CT) scanning⁴
  • The underlying histologic anatomy of the spleen largely determines its characteristic appearance on abdominal CT scan images. On unenhanced CT scan images, the spleen has an attenuation similar to that of the liver, approximately 40 henry (H). Normally, the liver and spleen densities are within 25 H on dynamic contrast-enhanced CT scan images.
  • In general, the spleen can be considered enlarged if its craniocaudal length is > 10 cm on conventional CT scans. A spleen that extends below the lower third pole of the kidney is also indicative of splenomegaly.
  • A CT scan remains the most useful preoperative investigation to measure splenic volume; to exclude lymph nodes at the splenic hilum; and to detect accessory spleens, splenic abscesses, and perisplenitis.
  • Findings that indicate radiologic distinction between benign and malignant lesions are inconsistent and cannot be relied upon to establish or refute a diagnosis of malignancy.
  • CT scanning is the imaging study of choice for identification of inflammatory changes.
  • CT scanning is sensitive for detecting mass lesions, calcifications, infarcts, and cysts.
• Splenoportography
  • This modality is used to evaluate portal vein patency and the distribution of collateral vessels before shunt operations for cirrhosis.
  • Findings can help identify the cause of idiopathic splenomegaly, especially in children.
• Angiography: Angiographic findings are used to differentiate splenic cysts from other splenic tumors.
• Liver-spleen colloid scanning
  • Erythrocytes are labeled with chromium-51 (⁵¹ Cr) , mercury-197 (¹⁹⁷ Hg), rubidium-81 (⁸¹ Rb), or technetium-99m (^99m Tc), and the cells are altered by treatment with heat, antibody, chemicals, or metal ions so that the spleen sequesters them after infusion.
  • A spleen length >14 cm is consider enlarged on liver-spleen scan
  • A spleen scan is a good noninvasive technique for evaluating spleen size; a close correlation exists between spleen length on the scan images and spleen weight after splenectomy.
  • A spleen scan is useful for detecting space-occupying lesions in the splenic substance, evaluating loss of spleen functions, assessing for the absence of a spleen, or determining the presence of an accessory spleen.
• Ultrasonography: This is a noninvasive, highly sensitive, and specific imaging technique for the evaluation of spleen size.

Procedures

History and physical examination, laboratory studies, and CT scanning can help clinicians determine the etiology of splenomegaly in greater than 90% of cases. Occasionally, it is necessary to obtain splenic tissue for pathologic evaluation.

• Splenectomy
  • Splenectomy may be considered in certain individuals to determine the etiology of splenomegaly.^5,6,7,8,9 The need for a diagnosis must be carefully weighed against the confounding morbidity associated with the asplenic state. Splenectomy is typically performed laparoscopically; even supramassive spleens can be removed by laparoscopic surgery with minimal morbidity.^9,10
  • Splenectomy is therapeutic in individuals with severe pancytopenia due to splenomegaly.
• Splenic biopsy
  • Splenic biopsy may be performed in specialized institutions. Severe bleeding is a frequent complication that limits the usefulness of this procedure.

Histologic Findings

When referring to an enlarged spleen as hypertrophied, the underlying cause may be hypertrophy or hyperplasia of individual cells. In specific diseases, the splenic architecture is remodeled. For example, in Niemann-Pick disease, sphingomyelin and cholesterol accumulate within large foamy cells, which is characteristic of this disease. With amyloidosis involving the spleen and resulting in splenomegaly, large hyaline masses are seen as lesions occupying the white pulp space. Two forms exist, including the "sago spleen," in which amyloid deposits are limited to follicles, and the "lardaceous spleen," in which amyloid is deposited in the walls of the splenic sinusoids. In a rare complication of typhoid fever, reactive splenic vasculitis may develop.

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