Primary
angiosarcoma of the spleen is a rare
neoplasm that has not been well characterized. We describe the clinical, morphologic, and immunophenotypic findings of 28 cases of primary splenic
angiosarcoma, including one case that shares features of
lymphangioma/
lymphangiosarcoma. The patients included 16 men and 12 women, aged 29 to 85 years, with a mean of 59 years and median of 63 years. The majority of patients (75%) complained of
abdominal pain, and 25% presented with
splenic rupture. The most common physical finding was
splenomegaly (71%). Seventeen of 21 patients were reported to have
anemia. Macroscopic examination showed
splenomegaly in 85% cases. Sectioning revealed discrete lesions in 88% of cases, ranging from well-circumscribed firm nodules to poorly delineated foci of
necrosis and
hemorrhage associated with cystic spaces. Microscopically, the
tumors were heterogenous; however, all cases demonstrated at least a focal vasoformative component lined by atypical endothelial cells. Solid sarcomatous, papillary, and epithelioid growth patterns were observed. The solid sarcomatous component resembled
fibrosarcoma in two cases and malignant fibroushistiocytoma in one case.
Hemorrhage,
necrosis,
hemosiderin, extramedullary hematopoiesis, and intracytoplasmic hyaline globules were frequently identified. A panel of immunohistochemical studies revealed that the majority of
tumors were immunoreactive for at least two markers of vascular differentiation (CD34, FVIIIRAg, VEGFR3, and CD31) and at least one marker of histiocytic differentiation (CD68 and/or
lysozyme).
Metastases developed in 100% of patients during the course of their disease. Twenty-six patients died of disease despite aggressive
therapy, whereas only two patients are alive at last follow-up, one with disease at 8 years and the other without disease
at 10 years. In conclusion, primary splenic
angiosarcoma is an extremely aggressive
neoplasm that is almost universally fatal. The majority of splenic
angiosarcomas coexpress histiocytic and endothelial markers by immunohistochemical analysis, which suggest that some
tumors may originate from splenic lining cells.