Thrombocytosis in Malignancy: A Paraneoplastic Syndrome?

Area of Science:

• Hematology
• Oncology

Background:

• Elevated platelet count (thrombocytosis) can be secondary to various conditions, including malignancies.
• Paraneoplastic thrombocytosis is a specific type of reactive thrombocytosis associated with cancer.

Purpose of the Study:

• To report the incidence of paraneoplastic thrombocytosis in patients diagnosed with reactive thrombocytosis.
• To analyze the clinical characteristics and associated factors of paraneoplastic thrombocytosis.

Main Methods:

• Retrospective analysis of 159 patients diagnosed with reactive thrombocytosis over 10 years.
• Evaluation of patient data including platelet count, diagnosis timing, and exclusion of other reactive causes.
• Assessment of associated laboratory findings (fibrinogen, ESR, alpha2 globulins, 5-hydroxytryptamine) and clinical events (hemorrhagic or thrombotic accidents).

Main Results:

• Paraneoplastic thrombocytosis was identified in 54 patients (33.9%) with reactive thrombocytosis.
• Increased platelet count was most commonly observed at diagnosis or within the first year.
• Other causes of reactive thrombocytosis were present in 74% of patients; 35% experienced hemorrhagic or thrombotic events.
• Elevated fibrinogen, ESR, and alpha2 globulins were noted in about half of the patients, with normal intraplatelet 5-hydroxytryptamine levels.

Conclusions:

• Paraneoplastic thrombocytosis is a significant finding in patients with reactive thrombocytosis, necessitating careful diagnosis.
• Exclusion of all other reactive conditions is crucial before diagnosing paraneoplastic thrombocytosis.
• An elevated platelet count in cancer patients is often a reactive phenomenon, but paraneoplastic thrombocytosis should be considered.