The coexistence of a pancreatic papillary cystic tumor with hairy cell leukemia is reported. To the best of our knowledge this association has never been published. A 41-year-old man diagnosed with hairy cell leukemia developed a second malignancy that corresponded to a papillary cystic pancreatic tumor. The patient underwent splenectomy and a tumoral surgical resection, and is currently well at 21 months follow-up. A pathogenetic relationship between the two malignancies was not demonstrated. Hairy cell leukemia has been reported to be associated to a great number of different second malignancies. In contrast, only two papillary cystic tumors of the pancreas have been described associated to a second neoplasm, a papillary thyroid carcinoma and a colonic carcinoma. This unusual benign or low-grade malignant pancreatic tumor more commonly occurs in the tail of the pancreas of young women. We want to stress the unusual presentation of this pancreatic tumor affecting the head of the gland in a male patient as well as its coexistence with a hairy cell leukemia.