Thrombocytosis (plural: thrombocytoses) is a general term and is defined as a rise in platelet count to over two standard deviations above the normal range. Its exact quantitative definition is variable, but generally equates to a platelet count greater than 400-450x109 cells/L.
Although there are no direct imaging features, it is useful for radiologists to be familiar with the condition in interpreting imaging associated with complications.
Pathology
It can arise from a broad spectrum of pathologies, either primary or secondary:
- primary
- myeloproliferative neoplasms (MPNs)
- specific subtypes of myelodysplastic syndrome (MDS)
- MDS/MPN overlap syndromes - refractory anaemia with ringed sideroblasts and thrombocytosis
- secondary: due to another disorder (reactive)
- malignancies
- acute or chronic infection and inflammatory disorders (e.g. inflammatory bowel disease - Crohn disease)
- postsurgical status
- drugs / medications
- connective tissue disorders
- iron deficiency anaemia
- splenectomy
- recovery of bone marrow from stress (e.g. chemotherapy or alcohol)
- acute blood loss