Distinctive immunohistochemical staining in littoral cell angioma using ERG and WT-1

Littoral cell angioma (LCA) is a rare vascular tumor of the spleen. It has an immunohistochemical staining pattern that is somewhat distinctive but can still be occasionally confused with other vascular and stromal proliferations in the spleen. In this study, LCA was evaluated using Ets-related gene (ERG) and Wilms tumor-1 (WT-1), relatively recently described vascular markers. In addition, other vascular lesions including normal spleen, hemangiomas, hamartoma, peliosis, and sclerosing angiomatoid nodular transformation were evaluated using these stains. In LCA, ERG stains the endothelial cells of the tumor as expected. ERG also was uniformly positive in vascular elements of other lesions except peliosis. However, in contrast to most other vascular elements, LCA was negative for WT-1 staining. This staining pattern may prove useful in diagnosing LCA and may provide insight into the derivation of the distinctive tumor.