A Case of JAK2V617F-Negative Myeloproliferative Neoplasm in a Young Female Presenting With Extreme Thrombocytosis.

Thrombocytosis is a commonly observed condition in clinical practice and typically results from various pathophysiological factors, such as iron deficiency, blood loss, infection, medications, rheumatologic conditions, malignancy, asplenia, post-splenectomy, or familial factors. However, extreme thrombocytosis, defined as a platelet count > 10,000 K/UL (equal or greater than a million), is a rare occurrence. In this report, we present a compelling case of severe thrombocytosis attributed to underlying chronic myelogenous leukemia (CML), further complicated by coexisting iron deficiency. It is essential to emphasize that not all instances of extreme thrombocytosis are indicative of essential thrombocythemia. Hence, maintaining a high level of suspicion for non-ET myeloproliferative neoplasms (MPNs) such as CML, as well as other underlying conditions like iron deficiency anemia, is crucial for accurate diagnosis and timely management.