Cardiac Involvement in Mantle Cell Lymphoma: A Case of Suspected Myocardial Infiltration

Description of Clinical Presentation: A 43-year-old female patient was diagnosed with mantle cell lymphoma (MCL) two years prior to admission. She initially presented with cervical lymphadenopathy, fatigue, and mild B symptoms. Despite two standard treatment lines (R-CHOP, followed by R-DHAP) and an attempt at autologous transplantation, the disease proved refractory, with progressive lymphadenopathy. One year later, she received palliative dexamethasone and a short trial with acalabrutinib, both without sustained response. The patient was then referred for evaluation in the GLOBRYTE clinical trial. At that time, she remained in good general condition with palpable cervical adenopathy. However, serial echocardiograms demonstrated progressive increase in the left ventricle (LV) wall thickness, raising suspicion of myocardial infiltration and prompting a cardiac magnetic resonance (CMR) examination.

Diagnostic Techniques and Their Most Important Findings: CMR cine sequences showed normal chambers volumes and normal biventricular systolic function, but revealed marked concentric LV hypertrophy with basal septal thickness up to 23 mm. Transthoracic echocardiograms, obtained within two months of the CMR, initially measured a basal septum of 9 mm, followed by 11 mm. CMR also showed diffuse mid-myocardium late gadolinium enhancement in the basal to mid anterior, anteroseptal, lateral, and inferior walls, in keeping with non-ischemic myocardial infiltration.

Whole-body 18FDG-PET/CT, performed alongside the CMR, revealed significant metabolic activity in the basal septum and in the basal lateral wall, along with increased uptake in the cervical and abdominopelvic lymph nodes.

One month later, a subsequent whole-body 18FDG-PET/CT, after new chemotherapy sessions, demonstrated complete metabolic resolution of the cardiac findings, confirming the initial suspicion of lymphocytic infiltration of the heart.

Learning Points from this Case: This case showcases the role of CMR in detecting and characterizing myocardial infiltration in lymphomas. Multimodality assessment was essential for the definite diagnosis. Whilst echocardiography showed only subtle remodeling, CMR identified massive hypertrophy with diffuse late gadolinium enhancement, allowing differentiation between tumor infiltration and ischemic/other left ventricle hypertrophy patterns. Whole-body 18FDG-PET/CT contributed to establishing the diagnosis by identifying metabolic response and confirming regression of cardiac infiltration after chemotherapy.

In non-Hodgkin lymphoma, integration of CMR and 18FDG-PET/CT is pivotal for diagnosis and prognosis of cardiac involvement. Particularly, in this case of mantle cell lymphoma, although rare, early recognition of myocardial infiltration was crucial for clinical management and outcome.

CMR cine SSFP images showing LV hypertrophy
CMR LGE images showing diffuse LGE in the myocardium
FDG-PET evolution during treatment