Angiosarcomas of the spleen are rare malignant splenic neoplasms. The term is usually given to describe a primary angiosarcoma of the spleen although angiosarcoma elsewhere can also rarely metastasise 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 recognised gender predilection (occurs almost equally in females and males) 1,17. Occasional publications, however, suggest a slight male predilection 4. Commonly seen in older patients, with the peak incidence is thought to be around the 6th decade.
Clinical symptomatology can be highly variable, often posing difficult diagnostic problems.
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 haemorrhage associated with cystic spaces.
Microscopically, the tumours 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.
Unlike with primary hepatic angiosarcoma, 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.
Reported sonographic features include splenomegaly with largely heterogeneous echotexture, including cystic and solid components 4,17. Increased vascularity on Doppler is commonly present 17.
CT may show solitary or multiple nodular masses of heterogeneous low attenuation in an enlarged spleen; necrosis and haemorrhagic areas may account for the heterogeneity 17. There is generally irregular and poorly defined contours 16.
Occasional large subcapsular intrasplenic or perisplenic extracapsular blood collections (haemoperitoneum) 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 scans may show a moderate splenomegaly with a micronodular involvement of the organ 16.
- pre-contrast CT: the tumours may appear hyperattenuating due to components of acute haemorrhage
- dynamic contrast-enhanced CT scans: the lesions may exhibit substantial peripheral contrast enhancement similar to that of hepatic haemangiomas 4
Reported MRI features include:
T1 and 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 haemorrhage, as well as tumour necrosis
- areas of decreased signal intensity within the tumour, owing to chronic haemorrhage with haemosiderin deposition
- C+ (Gd): usually shows intense and multinodular (heterogenous 15) enhancement with focal areas of non-enhancement, likely representing intratumoral haemorrhage and necrosis
Treatment and prognosis
It is an extremely aggressive fatal neoplasm at is almost universally fatal (median survival at approximately 24-36 months at the time of initial writing11) despite treatment 3,5. Distant metastases occur most frequently in the liver (approximately 70% of cases), lung, pleural lymph nodes, bone, and brain. Prompt splenectomy prior to splenic rupture may improve survival 5.
- spontaneous splenic rupture 2,4: can occur in up to 30% of cases 4
History and etymology
It was first described in 1879 by T Langhans 1.
General imaging differential considerations include vascular splenic lesions such as:
- splenic haemangioma
- Littoral cell angioma of spleen
- lymphangioma of spleen
- haemangiopericytoma of spleen
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- normal appearance of the spleen
- pseudolesion of the spleen: inhomogeneous splenic enhancement
splenic lesions and anomalies
- congenital anomalies
- mass lesions
- infiltrative processes
- incidental splenic lesion (approach)