Splenic angiosarcoma

Last revised by Joshua Yap on 7 Sep 2022

Splenic angiosarcomas are rare malignant splenic neoplasms. The term is usually given to describe a primary angiosarcoma of the spleen although angiosarcomas elsewhere can also rarely metastasize to the spleen. Despite its absolute rarity, a splenic angiosarcoma is considered the most common primary non-hematolymphoid splenic malignancy 2,17.

The general consensus is that there is no recognized gender predilection (occurs almost equally in females and males) 1,17. Occasional publications, however, suggest a slight male predilection 4. They are commonly seen in older patients, with the peak incidence thought to be around the 6th decade.

Unlike with primary hepatic angiosarcomas, there is no known association between splenic angiosarcoma and occupational exposure to chemicals, such as vinyl chloride or arsenic, or prior injection with the contrast agent thorium dioxide 4.

Clinical symptomatology can be highly variable, often posing difficult diagnostic challenges.

Macroscopic examination often shows splenomegaly with cut sections revealing discrete lesions in a majority of cases. These can range from well-circumscribed firm nodules to poorly delineated foci of necrosis and hemorrhage associated with cystic spaces.

Microscopically, the tumors are often heterogeneous. The lesions typically demonstrate focal vasoformative component lined by atypical endothelial cells. Solid sarcomatous, papillary, and epithelioid growth patterns can be observed.

Reported sonographic features include splenomegaly with largely heterogeneous echotexture, including cystic and solid components 4,17. Increased vascularity on color Doppler is commonly present 17.  

CT may show solitary or multiple nodular masses of heterogeneous low attenuation in an enlarged spleen; necrosis and hemorrhagic areas may account for the heterogeneity 17. There are generally irregular and poorly-defined contours 16.

Occasional large subcapsular intrasplenic or perisplenic extracapsular blood collections (hemoperitoneum) may be present.

Some of these masses may show peripheral enhancement with the margins of the lesions often irregular or poorly-defined.

Less frequently, CT may show a moderate splenomegaly with a micronodular involvement of the organ 16.

  • pre-contrast CT: the tumors may appear hyperattenuating due to components of acute hemorrhage
  • dynamic contrast-enhanced CT scans: the lesions may exhibit substantial peripheral contrast enhancement similar to that of hepatic hemangiomas 4

MRI features include:

  • T1/T2
    • nodular hypointense (relative to the normal adjacent splenic parenchyma) masses on both T1- and T2-weighted images
    • large masses with increased signal intensity on both T1- and T2-weighted images that are likely related to areas of subacute hemorrhage, as well as tumor necrosis
    • areas of decreased signal intensity within the tumor, owing to chronic hemorrhage with hemosiderin deposition
  • T1 C+ (Gd): usually shows intense and multinodular (heterogenous) 15 enhancement with focal areas of non-enhancement, likely representing intratumoral hemorrhage and necrosis

It is an extremely aggressive neoplasm that is almost universally fatal despite treatment, with a median survival of around 24-36 months 3,5,11. Distant metastases occur most frequently in the liver (~70% of cases), lungs, pleural lymph nodes, bone, and brain. Prompt splenectomy to prevent splenic rupture may improve survival 5.

It was first described in 1879 by T Langhans 1.

General imaging differential considerations include vascular splenic lesions such as:

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