Simultaneous presentation of hairy cell leukemia and metastatic signet ring carcinoma of the stomach diagnosed by bone marrow biopsy.

Hairy cell leukemia (HCL) is a rare chronic B-cell disorder with an increased risk of second tumors. The relative risk of second cancers reported in various series of HCL patients ranged from 0.95 to 4.33, but simultaneous presentation of HCL and other epithelial malignancies is very rare. To our knowledge, we present the first case of the coexistence of signet ring carcinoma of the stomach and HCL. We report a case of the simultaneous presentation of HCL and metastasis of the primary signet ring cell carcinoma of the stomach to the bone marrow and skin. A bone marrow biopsy was performed on a patient with pancytopenia. A histologic examination with immunostaining of the bone marrow specimen showed the presence of signet ring carcinoma cells in addition to HCL. As a consequence, our patient underwent further diagnostic procedures including endo-gastro-duodenoscopy with biopsy of gastric tumor mass, which established the diagnosis of gastric signet ring cell carcinoma.