Splenic neoplasms

Question 1

Answer 1

Littoral cell angioma

A benign vascular tumor of the spleen.

Histologically, a proliferation of anastomosing, tortuous, blood filled vascular channels with irregular channel lumina, often with papillary projections and cystic spaces. The spaces are lined by tall endothelial cells with variable hemophagocytosis. Sloughing of endothelial cells into vascular spaces is common.

The vascular spaces are filled with blood and lined by both tall and flat cells that uniquely express both endothelial and histocytic markers (i.e., CD68 and CD163).

Question 2

Answer 2

Splenic hemangioma

At the cellular level, the vessels are thin walled, and there is no atypia or mitosis in the endothelial cells. The endothelial cells lining the vessels may be flat or plump. There should be no necrosis or solid areas anywhere in the lesion.

Question 3

Answer 3

Splenic peliosis

Not really a neoplasm. Characterized by blood-filled cavities haphazardly scattered throughout the splenic red pulp. Isolated splenic lesions in peliosis are rare, with most cases also presenting with blood filled cysts in the liver. Blood filled cavities in peliosis generally lack an endothelial lining.

Question 4

Answer 4

Splenic hamartoma

Disorganized sinuses and splenic red pulp elements ( * ) compared with the organized sinuses in the normal spleen (upper portion of the image).

Question 5

Answer 5

Splenic lymphangioma

Splenic lymphangioma shows thin-walled cystic spaces filled with proteinaceous fluid ( * ). Attenuated endothelial cells (arrow) line the cysts.

Question 6

Answer 6

Splenic angiosarcoma

Diffusely infiltrative achitecture with focal areas of hemorrhage ( * ). Cells show irregular, hyperchromatic nuclear pleomorphism and mitotic activity.