Abstract: Mycosis fungoides is the most common cutaneous T-cell lymphoma. Although myocardial infiltration is frequent in advanced stages, symptomatic cardiac involvement is rare. We report an unusual case of rapidly progressing acute heart failure due to cardiac affection by mycosis fungoides manifested as an intracavitary mass in the right atrium. The patient received cytoreductive surgery and adjuvant radiotherapy, presenting an excellent cardiovascular outcome during follow-up.
