“Not another one!” Making sense of CT and MR imaging features of focal splenic masses Sara Smolinski 1 MD, Michael Morrow 1 DO, Qiqing Ge 1 MD, Shirley McCarthy 2 MD, Alena Kreychman 1 MD, and Dmitry Rakita 1 MD 1 Baystate Medical Center, 2 Yale New Haven Hospital References 1. Abbot RM, et al. Primary Vascular Neoplasms of the Spleen: Radiologic-Pathologic Correlation. Radiographics 2004; 24:1137-1163. 2. Ahmed S, et al. Splenic Incidentalomas. Radiol Clin N Am. 2011;49: 323-47. 3. Ekeh AP, et al. The prevalence of incidental findings on abdominal computed tomography scans of trauma patients. J Emerg Med 2010;38(4):484–9. 4. Lam KY et al. Metastatic tumors of the spleen. A 25-year clinicopathologic study. Arch Pathol Lab Med. 2000; 124:526-530. 5. Levy AD, et al. Littoral cell angioma of the spleen: CT features with clinicopathologic comparison. Radiology 2004; 230:485–490. 6. Luna A, Ribes R, et al. MRI of Focal Splenic Lesions Without and With Dynamic Gadolinium Enhancement. AJR 2006; 186:1533-1547. 7. Paluska TR, et al. Incidental CT findings in trauma patients: incidence and implications for care of the injured. J Trauma 2007;62:157–61. 8. Warshauer DM, et al . Imaging Manifestations of Abdominal Sarcoidosis. AJR 2004; 182:15-28. The majority of splenic lesions are incidentally detected on routine abdominal CT, typically performed for other indications. In an emergency room population being scanned for abdominal pain or trauma, incidental splenic lesions were seen in approximately 1% of patients and the vast majority of these were considered clinically benign. 3,4 It is important to combine clinical factors with imaging findings for the most accurate evaluation. Relevant findings include abdominal pain, signs or symptoms of infection, immune status, history of malignancy, associated imaging findings or history of abdominal trauma. In this poster, we review the most common splenic lesions encountered and propose an algorithm for their diagnosis and management. Incidental Splenic Lesions Splenic Cyst “True” congenital or parasitic cysts (20%) possess an epithelial lining. Pseudocysts (80%), are posttraumatic without an epithelial lining. Typically asymptomatic, cysts may enlarge or hemorrhage, causing pain or may be the sequela of prior trauma. 1,2 images demonstrate a uniformly T2 hyperintense, non enhancing mass. The lesion was resected for symptomatic relief. Histology demonstrated a congenital cyst with stratified squamous epithelial wall. Hemangioma Composed of a proliferation of vascular channels, ranging from capillary to cavernous. Most commonly singular but may be multiple. Typically asymptomatic. Multiple hemangiomas are associated with Klippel-Trenaunay-Weber syndrome or Kasabach-Merritt syndrome. 1,2 Figure 2. 44 year old male with history of melanoma found to have an enhancing splenic mass on a contrast enhanced staging CT (a). (b) SSFSE image demonstrates a T2 hyperintense mass. (c-e) T1 fat suppressed GRE images obtained pre, immediately and 1 minute post contrast administration demonstrate a T1 hypointense mass with initial peripheral and subsequent homogeneous enhancement, consistent with a splenic hemangioma. Follow up imaging demonstrated one year stability. Hamartoma Composed of a disorganized vascular channels and fibrotic red or white pulp elements. Most are asymptomatic, although may present with pain, palpable mass or rupture if large. Associated with tuberous sclerosis and Wiskott-Aldrich-like syndrome. 1,2 upper abdominal pain. (a) SSFSE image demonstrates a homogeneous, mildly T2 hyperintense splenic mass which creates a contour abnormality. (b) On the T1 GRE opposed phase image the mass is isointense to the spleen (c-d) Multiphase subtraction post contrast GRE images demonstrates progressive homogeneous enhancement. Interval growth of the mass led to resection and a histological diagnosis of hamartoma. Littoral Cell Angioma Rare vascular splenic neoplasm arising from littoral cells, which line the splenic red pulp sinuses and are believed to play a role in the immune response. May be asymptomatic or can present with abdominal pain, splenomegaly, anemia, thrombocytopenia and constitutional symptoms. Typically benign but rare reports of malignant behavior, including metastasis. May be solitary or numerous. 1,2,6 mass isointense to normal splenic parenchyma. (b) Fat suppressed non contrast GRE image demonstrates the mass to be hypointense to isointense to the spleen. (c) Multiphase post contrast subtraction GRE images demonstrate initial hypointensity with progression to isointensity on the equilibrium phase (d). Growth led to resection and a histological diagnosis of littoral cell angioma. Infection Lymphangioma Sarcoidosis Most commonly seen with concurrent hepatic abscesses and sepsis. Fungal microabscesses most common, in an immunocompromised patient. Tuberculosis typically presents as coalescing micronodules or wedge shaped peripheral septic emboli. 1,2 a b c Figure 7. 48 year old female with abdominal pain and fever. (a-b) Multiple ill-defined T1 hypointense and T2 hyperintense intrasplenic and subcapsular fluid collections consistent with abscesses. (c) CT imaging reveals multiple subcapsular fluid collections with smaller intraparenchymal fluid collections. (d) SSFSE image demonstrates a concurrent fluid collection in the liver. Fluid aspirate grew Streptococcus intermedius. Figure 8. 40 year old immuno- compromised female with fever and abdominal pain. Congenital abnormality of lymphatic tissue. May be capillary, cavernous or cystic. May be solitary, scattered or diffuse. Typically asymptomatic, however may present with abdominal pain, hemorrhage or thrombocytopenia. 1,2 Lymphoma Most commonly presents as part of systemic disease, less commonly as primary splenic lymphoma. May present as multiple nodules, heterogeneous infiltration or diffuse splenomegaly. Often with accompanying retroperitoneal lymphadenopathy. 2 Figure 11. 34 year old male with pancytopenia. Contrast enhanced CT demonstrates diffuse enlargement and heterogeneous attenuation of the spleen. The patient underwent splenectomy for pain and thrombocytopenia. Histology demonstrated marginal zone lymphoma. Figure 12. 56 year old female with with abdominal pain. Contrast enhanced CT demonstrates splenomegaly with innumberable hypoattenuating nodules and retroperitoneal lymphadenopathy. Lymph node biopsy demonstrated Hodgkin lymphoma. Typically presents with multiple non-caseating granulomas on histology. Only 10% of patients present with solely extra- pulmonary findings. May be associated with liver involvement and thoracic and abdominal lymphadenopathy. Most patients with splenic involvement are asymptomatic, although hypercalcemia may be present. 2,5,8 a b c Intense and heterogeneous enhancement Heterogeneous Heterogeneous Angiosarcoma Hypointense on immediate postcontrast images, occasionally rim-enhancing intense and heterogeneous enhancement Hyperintense Hypo - Isointense Metastases Hypointense immediately after contrast administration, then isointense on delayed Hypointense Isointense Lymphoma Peripheral enhancement when encapsulated; septations may enhance Hyperintense Hypo - Isointense Infection Minimal peripheral enhancement on delayed Hypointense Hypointense Sarcoidosis Homogeneous progressive enhancement Variable Hypointense Littoral Cell Angioma No internal enhancement; peripheral enhancement in cystic forms; progressive septal in cavernous and capillary forms Hyperintense Hypointense Lymphangioma Heterogeneously diffusely enhancing on early imaging, isointense or hyperintense on delayed Hyperintense Isointense Hamartoma Homogeneous brisk or progressive mottled enhancement Hyperintense Hypointense Hemangioma No enhancement Hyperintense Hypointense Cyst Enhancement Pattern T2 T1 Pathology Common MRI Characteristics Metastases Only 3% of metastases are to the spleen. Occurs late in the disease, with concurrent involvement of other organs. Most common sources are breast, lung, and melanoma. 4 Figure 13. 60 year old female with history of breast cancer. Contrast enhanced CT demonstrates diffuse hypoattenuating nodules throughout the spleen. Figure 14. 64 year old male with history of lung cancer. Contrast enhanced CT demonstrates innumerable heterogeneous hypoattenuating nodules throughout the spleen and liver with an area of necrosis in the largest splenic metastasis. a b c d a b c d a b c d a b c d b c d e a circumscribed largely hypoattenuating mass in the anterior spleen. (b) SSFSE image demonstrates a hyperintense mass with hypointense septae. (c) Noncontrast fat-suppressed GRE image demonstrates a hypointense mass. (d) Septal enhancement is demonstrated on an image obtained 5 minutes post contrast administration. Histology was consistent with lymphangioma. (a) Innumerable hypoattenuating nodules throughout the spleen on a contrast enhanced CT. (b-c) SSFSE and fat suppressed noncontrast GRE images demonstrate innumerable hypointense nodules. The nodules demonstrate mild peripheral enhancement without internal enhancement, as seen on a post contrast axial GRE image (d) consistent with sarcoid granuloma. Splenic Mass(es) on CT Symptoms +/- Other organ involvement +/- Abnormal lab values Asymptomatic Pain attributable to the spleen Simple Cyst(s) Differential, with typical clinical findings: - Sarcoidosis (Hypercalcemia) - Lymphoma (Bulky lymphadenopathy) - Infection (Sepsis) - Metastases or metastatic primary splenic angiosarcoma (Other organs) Rarely symptomatic benign neoplasms: - Hamartoma - Hemangioma - Lymphangioma - Littoral cell angioma (All listed here may present with thrombocytopenia or anemia, littoral cell angioma may present with fever and constitutional symptoms) MRI Indeterminate Solid Mass Differential: - Hamartoma - Lymphangioma - Littoral cell angioma - Odds of asymptomatic angiosarcoma exceedingly small Surgical consult, MRI if further characterization warranted Classic hemangioma or hemorrhagic cyst Imaging follow up in 6-12 months to assess for growth Differential: - Lymphangioma - Littoral cell angioma - Large benign mass or cyst with recent hemorrhage causing capsular stretching Differential: - Pseudocyst - Congenital cyst - Echinococcus (very rare, laboratory evidence) No follow up imaging No follow up imaging Further imaging may not be necessary Figure 1. 14 year old female with upper abdominal pain and a large splenic cyst. (a) Contrast enhanced CT demonstrates a fluid attenuation mass. MRI performed 1 year later when patient developed pain. (b-c) T2 fat-saturated FSE and post contrast fat-saturated GRE Figure 6. 55 year old female with elevated liver enzymes and a history of sarcoidosis, diagnosed by lymph node biopsy Angiosarcoma Consists of disorganized vascular channels. Rare and aggressive, presenting with diffuse metastasis to liver, lung, bone, and lymphatic system. May present with abdominal pain, fever, fatigue, weight loss, anemia, thrombocytopenia, or coagulopathy. High risk of spontaneous rupture. 1,2,6 nodule in the spleen. Heterogeneity is consistent with internal hemorrhage. (b) Fat suppressed non contrast GRE image demonstrates a mixed signal intensity nodule in the spleen, related to presence of internal hemorrhage. Two other similar appearing nodules were noted in the spleen (not shown). Figure 16. 43 year old male with abdominal pain and hypotension, related to spontaneous rupture of a metastatic splenic angiosarcoma. a b Contrast enhanced CT image demonstrates heterogeneous masses in the liver and spleen with hemoperitoneum (Images courtesy of Barak Friedman MD, NSLIJ, NY) Figure 15. 81 year old female with epigastric pain. (a) Fat suppressed T2 FSE demonstrates a mixed signal intensity exophytic Figure 3. 46 year old female with ulcerative colitis and Figure 4. 48 year old female with an incidental splenic mass on CT. (a) Contrast enhanced CT demonstrates a Figure 5. 37 year old female with history of ulcerative colitis and sclerosing cholangitis. (a) SSFE demonstrates a Contrast enhanced CT demonstrates numerous hypoattenuating foci in the liver and spleen, a typical imaging presentation of fungal microabscesses. Blood cultures were positive for Candida albicans. d