1. A case of the rare disorder cyclic neutropenia with giant follicular lymphoblastoma and lymphosarcoma is reported.
2. Adrenocorticotropic hormone administration during a neutropenic phase resulted in a further depression of the total leukocyte count and no significant change in the already very low neutrophil count. Cortisone did not prevent or ameliorate a recurrence of neutropenia.
3. Splenectomy resulted in less depression of the total leukocyte and neutrophil values and a considerable amelioration of the symptoms during the continued cycles; however, because of the short follow-up, a definite statement on the long range value of splenectomy cannot be made.
4. The pathogenesis of cyclic neutropenia is discussed with particular reference to its relationship to lymphoma and hypersplenism.