B-cell prolymphocytic leukemia (B-PLL) was recognized as a distinct entity in the fourth edition of the World Health Organization (WHO) classification for hematolymphoid neoplasms (WHO-HAEM4); however, its de novo presentation has been removed from the upcoming 5th edition classification (WHO-HAEM5). We present a case of a 65-year-old man with leukocytosis, fatigue, and no organomegaly by imaging. Bone marrow examination showed a prolymphocytoid population comprising 78% of the marrow elements. After thorough exclusion of other entities by clinical parameters and ancillary methods, we concluded that this case represents a de novo case of B-PLL.