Chronic Myeloid Leukemia (CML): This condition often presents with an elevated white blood cell count (WBC) due to increased neutrophils, which aligns with the high neutrophil count mentioned. The high Mean Corpuscular Volume (MCV) could be seen in some cases, especially if there's a reactive component or associated vitamin B12/folate deficiency. Low Red Cell Distribution Width (RDW) suggests a uniform population of red blood cells, which can be seen in CML due to the clonal nature of the disease affecting hematopoiesis.

Reactive Neutrophilia: This is a common response to infection, inflammation, or stress, leading to an elevated WBC count with a predominance of neutrophils. The high MCV could be due to a concurrent condition such as vitamin B12 or folate deficiency, and a low RDW might not be directly related but could be seen in the context of a uniform response to a stimulus.
Polycythemia Vera: Although primarily known for causing an increase in all three blood cell lines (erythrocytosis, leukocytosis, and thrombocytosis), it can present with a high MCV if there's an associated deficiency or if the erythrocytosis is not the dominant feature at the time of diagnosis. The low RDW and high neutrophils could fit, especially if the disease is at an early stage or not fully expressed.

Acute Myeloid Leukemia (AML): While AML can present with a wide range of blood cell abnormalities, it's crucial not to miss due to its aggressive nature and need for prompt treatment. A high WBC with neutrophilia, along with abnormalities in MCV and RDW, could be seen, especially if there's a maturation arrest or if the disease is affecting erythropoiesis.
Sepsis: A severe infection leading to sepsis can cause a significant elevation in WBC count with a left shift (increased neutrophils), and while MCV and RDW might not be directly affected, their abnormalities could be overlooked in the context of a critical illness.

Myeloproliferative Neoplasms (MPN) other than CML or PV: Conditions like essential thrombocythemia or primary myelofibrosis can occasionally present with elevated WBC counts and abnormalities in red cell indices, although they are less common than CML or PV.
Congenital Neutrophilia: A rare condition characterized by a persistent and isolated increase in neutrophil count without an apparent cause, which could be considered if other diagnoses are ruled out and the condition persists over time.