ABSTRACT
Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative neoplasm characterized by sustained neutrophilia, splenomegaly, and hypercellular bone marrow without Philadelphia chromosome. Diagnosis of CNL requires exclusion of identifiable causes of reactive neutrophilia, such as infection and tumors. Our patient presented with general weakness and weight loss. Computed tomography (CT) showed a mass in the distal rectum, which was confirmed to be an adenocarcinoma by colonoscopic biopsy. Positron emission tomography-CT showed multiple liver, bone, and lymph node metastases. Liver and lymph node biopsies revealed neutrophilic infiltration with no evidence of adenocarcinoma. The pathological findings of the bone marrow were compatible with CNL. Cytogenetic analysis revealed a normal karyotype, and molecular analysis was negative for BCR/ABL. Here, we present a 73 year-old man diagnosed with concurrent CNL and rectal cancer.