Papillary fibroelastoma of the papillary muscle – a case report on a rare entity and sometimes a delayed diagnosis

Background Papillary fibroelastoma, generally affecting the valve endocardium, is one of the most common benign cardiac tumors. Although rarely reported, atypical localization of such tumors complexifies diagnostic and might negatively impact patient outcomes due to late detection. Case summary We present the case of a 69-year-old female patient presenting for a check-up consultation and reporting symptoms of dysesthesia, aphasia and dizziness. The patient had an history of atrial fibrillation on anticoagulation with rivaroxaban starting 6 years prior to presentation. Further examination using transthoracic and transesophageal echocardiography revealed a hyperechogenic structure at the level of the subvalvular apparatus of the mitral valve. Interestingly, when cardiac MRI was subsequently performed, this diagnosis could not be confirmed. This discrepancy might be linked to the lower spatial and temporal resolution compared to transesophageal echocardiography, or transthoracic echocardiography with high-frequency probe. To further investigate the symptoms of dysesthesia, aphasia and dizziness a cerebral MRI was performed and revealed multiple, bilateral ischemic lesions. Considering the findings and the symptoms of the patient, choice was made to perform explorative surgery. Intraoperatively, a 8mm structure was identified and removed from the basis of the posteromedian papillary muscle. Histological examination revealed a papillary fibroelastoma. The patient was discharged on postoperative day 10. At follow-up, there was no report of neurological symptoms. Discussion This case shows a highly atypical localization of a rare cardiac tumors and exemplifies the importance of multimodal diagnostic prior to cardiac surgery.