[Cyclic thrombocytopenia complicated with Sjögren syndrome and the mechanism of periodic platelet count fluctuation].

Cyclic thrombocytopenia is a rare disorder with periodic changes of the platelet count. We experienced a patient with cyclic thrombocytopenia and Sjögren syndrome (SS), and studied the mechanism of the cyclic changes of the platelet count. The patient, a 75-year-old woman, was referred to our hospital because of dry mouth, dry eyes, and severe thrombocytopenia.