Cardiac ALL: Most Unusual Occurrence of Lenalidomide-associated Acute Lymphoblastic Leukemia with Subsequent Cardiac Involvement

Leukemic infiltration of the myocardium is an extremely rare complication and requires high clinical suspicion, as <5% pf patients are symptomatic. Commonly encountered cardiovascular complications are secondary to anemia, infections, and chemotherapy. We present an unusual case of biopsy-proven myocardial B-cell acute lymphoblastic leukemia (ALL) in an elderly male on chronic maintenance therapy with lenalidomide, with a previous history of multiple myeloma (MM) and subsequent ALL. Lenalidomide is a Category 1 recommendation for primary and maintenance therapy of MM, but there is growing evidence of secondary primary malignancies (SPMs). Despite this increase in SPM, the overall survival (OS) benefit associated with the use of maintenance immunomodulatory (IMID) therapy in multiple myeloma outweighs the risk of SPMs. Only age-appropriate screening methods are recommended. This case report serves as an important reminder of a rare manifestation of leukemia and presents as anecdotal evidence of response to the monoclonal antibody inotuzumab for visceral involvement of ALL, which has not been reported to our knowledge and requires further exploration.