Abstract: Objective： To investigate the clinicopathological features, morphological characteristics, immunophenotypes of littoral cell angioma (LCA) in spleen, and to provide new evidence for making diagnosis and avoiding misdiagnosis. Methods: Clinicopathological data, histological characteristics of 13 cases of LCA were retrospectively studied and immunohistochemical staining was imposed on the paraffinembedded specimens, and 5 cases of cavernous hemangioma, 4 cases of normal littoral cells of spleens were used as control groups, simultaneously. Results: All the 13 LCA patients included 7 males and 6 females, aged from 39 to 70 years with an average of 54. 2 years and a median age of 55 years. Among these tumor patients, 6 cases were accompanied by malignances, benign tumors or inflammation states at abdominal cavities, and 7 cases were accidentally discovered by physical examinations. Grossly, spleens contained solitary or multiple gray red nodules ,which ranged from 0.5 to 6.2 cm in diameter. Histologically, tumors were composed by anastomosing vascular spaces which were lining by plump, rounded to cuboidal littoral cells that extended into vascular lumens. Usually, papillary frameworks that were covered by these cells were also seen extending into the lumens in some areas. Other types of histiocytoid cells were identified in lumens and the sizes were larger than the littoral cells. Both types of cells absented cytologic atypia. Immunohistochemical study demonstrated that the littoral cells in all cases were positive for vascular endothelial and histiocyte markers, such as CD21, CD31, CD68, polyclone FⅧRAg and ERG, while these cells were negative for CD8, CD34, and WT-1. These findings manifested that immunophenotype of littoral cell in LCA distinctive from that in controls. Conclusion: LCA is a benign lesion, which frequently occurs in the elderly. Its etiology remains confusion, however, immune dysregulation may associate with it because of the concomitance with other tumor or inflammation in some cases. The littoral cells in LCA show a hybrid endothelialhistiocytic phenotype on immunohistochemistry, therefore these cells may have features that intermediate between those of endotheliocytes and histiocytes. Emphasizing the histological findings and immunophenotypes is significant for diagnosis and differential diagnosis.

Key words: littoral cell angioma, immunophenotyping,Pathology, clinical, Diagnosis, Diagnosis differential