Introduction:
Metastasis to the spleen from different neoplasms is rare, though in autopsy about 1.6-30% of patients with cancer have metastasis to the spleen (1)The most common tumors that metastasized to the spleen have been lung cancers, breast cancers, and melanoma (2). The spleen plays an important role in hematopoiesis and immunosurveillance. The main functions of spleen include clearance of abnormal erythrocytes, removal of microorganisms, and IgG synthesis (3). Splenomegaly can rarely be the main sign of metastasis to the spleen (1). Generally, the pathophysiological mechanism of splenomegaly is categorized into congestive, infiltrative such as metastasis, immune, and neoplasm such as lymphoma (3).
Considering the rare prevalence of metastasis to the spleen various theories have been propounded: I) presence of a humoral substance in the spleen which causes degradation of tumor cells; II) presence of contractions in the spleen causing blood ejection from sinusoids into the splenic vein (1). In this study, one case of hairy cell leukemia and breast cancer with isolated metastasis to the spleen synchronously is reported considering its rarity.