PURPOSE:To retrospectively review clinical, pathologic, and imaging features of angiosarcoma of the spleen in 12 patients.MATERIALS AND METHODS:Institutional review board approval was obtained, and informed consent was not required. Records of 12 cases of proved angiosarcoma of the spleen were accessed from the files of the Armed Forces Institute of Pathology. Clinical, pathologic, and imaging findings were reviewed. Presenting signs and symptoms were recorded, and the pathologist confirmed the diagnosis and determined gross and microscopic morphologic findings in each spleen. Radiologists reviewed available images to determine the size of the spleen and mass, amount of splenic involvement by the tumor (if enhanced at computed tomography [CT] and magnetic resonance [MR] imaging), and amount of nonviable tumor determined as decreased echogenicity at ultrasonography (US) and lack of enhancement at CT and MR imaging. Imaging and pathologic findings were compared. Five US, 10 CT, three MR, and two angiographic images were reviewed by two experienced abdominal radiologists.RESULTS:There were seven men and five women (age range, 36-86 years; mean, 55 years). The most common symptom was upper abdominal pain in eight (67%) patients: Pain was acute for 24 hours prior to admission in one patient and chronic (range, 1-6 months) in seven patients. At imaging, the spleen was enlarged (>12 cm in length) in nine patients. The most common finding, seen in seven (58%) patients, was a complex mass or masses in an enlarged spleen. Four of these patients had evidence of metastases and one had intraperitoneal hemorrhage. Two patients had solitary hypervascular tumors and liver metastases. One patient had a normal-sized spleen with multiple lesions that ranged 2-3 cm in size, as well as metastases to the spine. The 11th patient had two small lesions, with small calcifications in the periphery of one lesion. The 12th patient had intraabdominal hemorrhage around the spleen and no obvious mass at CT. Tumor necrosis was confirmed at histologic evaluation in nine patients.CONCLUSION:The most common clinical finding was upper abdominal pain. Angiosarcoma of the spleen could be suggested in the majority of cases (83%) by using the imaging features of splenic mass with evidence of metastatic disease.

Primary vascular neoplasms of the spleen constitute the majority of non-hematolymphoid splenic tumors. The benign primary vascular tumors include hemangioma, hamartoma, and lymphangioma, whereas those of variable or uncertain biologic behavior include littoral cell angioma, hemangioendothelioma, and hemangiopericytoma. The primary malignant vascular neoplasm of the spleen is angiosarcoma. Peliosis is a rare lesion of unknown cause that is usually found incidentally in asymptomatic patients but may be associated with hematologic or metastatic disease. Although these vascular neoplasms of the spleen are uncommon, their importance lies in that they must be differentiated from the more common neoplastic disorders of the spleen, such as lymphoma and metastasis. The most common echogenic solid or complex cystic mass in an asymptomatic patient is splenic hemangioma. However, the imaging appearance of splenic hemangiomas may be complex, and differentiation of these lesions from malignant disease may not be possible. The diagnosis of splenic hamartoma may be suggested when findings of increased blood flow on color Doppler images are seen in association with a homogeneous solid echogenic mass. A large subcapsular solitary cystic abnormality discovered incidentally in a child in association with internal septations and tiny mural nodules favors the diagnosis of lymphangioma. Any invasion of the surrounding splenic parenchyma by a splenic lesion should indicate a more aggressive or malignant process. Evaluation of a focal splenic abnormality identified on sonograms should be followed up with computed tomography or magnetic resonance imaging with and without contrast material enhancement. Splenectomy may be required for definitive evaluation of a splenic mass with atypical features.

Primary vascular neoplasms of the spleen constitute the majority of nonhematolymphoid splenic tumors. The benign primary vascular tumors include hemangioma, hamartoma, and lymphangioma, whereas those of variable or uncertain biologic behavior include littoral cell angioma, hemangioendothelioma, and hemangiopericytoma. The primary malignant vascular neoplasm of the spleen is angiosarcoma. Peliosis is a rare lesion of unknown cause that is usually found incidentally in asymptomatic patients but may be associated with hematologic or metastatic disease. Although these vascular neoplasms of the spleen are uncommon, their importance lies in that they must be differentiated from the more common neoplastic disorders of the spleen, such as lymphoma and metastasis. The most common echogenic solid or complex cystic mass in an asymptomatic patient is splenic hemangioma. However, the imaging appearance of splenic hemangiomas may be complex, and differentiation of these lesions from malignant disease may not be possible. The diagnosis of splenic hamartoma may be suggested when findings of increased blood flow on color Doppler images are seen in association with a homogeneous solid echogenic mass. A large subcapsular solitary cystic abnormality discovered incidentally in a child in association with internal septations and tiny mural nodules favors the diagnosis of lymphangioma. Any invasion of the surrounding splenic parenchyma by a splenic lesion should indicate a more aggressive or malignant process. Evaluation of a focal splenic abnormality identified on sonograms should be followed up with computed tomography or magnetic resonance imaging with and without contrast material enhancement. Splenectomy may be required for definitive evaluation of a splenic mass with atypical features.