Tumor Lysis Syndrome (TLS): Given the patient's chemotherapy treatment for breast cancer, the development of pancytopenia, elevated ferritin, and CRP, along with plural embolic CVA, TLS is a strong consideration. TLS can lead to acute kidney injury, which might explain the elevated CRP and could be a precipitating factor for the embolic events due to hypercoagulability.

Disseminated Intravascular Coagulation (DIC): The combination of pancytopenia, elevated ferritin, and CRP, along with plural embolic CVA in a patient undergoing chemotherapy, suggests a coagulopathy. DIC is a known complication of cancer and its treatment, which can lead to both thrombotic and hemorrhagic events.
Sepsis: Although not directly implied, sepsis could explain the elevated CRP, pancytopenia, and potentially the embolic events if there's an associated endocarditis or another source of emboli. Sepsis is a concern in any immunocompromised patient, including those on chemotherapy.
Chemotherapy-induced Myelosuppression: This is a common side effect of chemotherapy, leading to pancytopenia. However, it doesn't fully explain the elevated ferritin, CRP, or the plural embolic CVA without considering additional complications like infection or thrombosis.

Catheter-related Thrombosis: In patients with central lines for chemotherapy administration, catheter-related thrombosis is a risk. This could lead to embolic events and should be considered, especially if the patient has a central venous catheter.
Infection (e.g., Endocarditis): Infections can cause embolic events, elevated inflammatory markers, and pancytopenia in immunocompromised patients. Endocarditis, although less common, is a critical diagnosis not to miss due to its high morbidity and mortality.
Hemophagocytic Lymphohistiocytosis (HLH): This rare condition can be triggered by infections, malignancies, or autoimmune disorders, leading to pancytopenia, elevated ferritin, and systemic inflammation. It's critical to consider HLH due to its aggressive nature and the need for specific treatment.

Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare, acquired, life-threatening disease of the blood characterized by the destruction of red blood cells, bone marrow failure, and the potential for thrombotic events. It could explain some of the patient's symptoms but is less likely given the context.
Thrombotic Thrombocytopenic Purpura (TTP): A rare blood disorder characterized by the formation of blood clots in small blood vessels throughout the body, which could lead to embolic events and pancytopenia. However, it's less directly related to the chemotherapy and cancer context compared to other diagnoses.