Incidental Diagnosis of Cyclic Thrombocytopenia: An Asymptomatic Case.

Cyclic thrombocytopenia (CTP) is a very rare condition that is characterized by episodic thrombocytopenia over a period of three to five weeks. The pathogenesis of CTP is unclear and most likely heterogeneous; however, usually there is no clue about the underlying disease. In this case report, we presented a 48-year-old female who had a low platelet count of 66 x 10/µL (range: 150-450 x 10/µL) on her routine examination with no evidence of bleeding. On further review of her laboratory workup in the past several years, she was noted to have multiple episodes of low platelet counts. She was diagnosed with CTP after a recurrent pattern of fluctuations in her platelet count, with improvements sometimes without intervention. Unfortunately, most CTP patients are misdiagnosed as having primary immune thrombocytopenia (ITP), and CTP typically responds poorly to ITP therapy. This case underscores the need for further research and serves as a valuable reference to increase the awareness of clinicians about CTP.