Importanţa evaluării computer-tomografice în detecţia interesării tumorale limfomatoase cardio-pericardice

Introduction

Any metastatic malignancy may involve the pe­ricar­dium, but hematologic malignancies tend to involve the pericardium and cardiac structures more often than the others^(1,2). Retrograde lymphatic, trans­venous and contiguous direct extension, as well as hematogenous spread are the main pathways for se­con­da­ry tumoral cardiac and pericardial involvement^(1,3). Ima­ging findings in pericardial involvement typically in­clude nodular or irregular pericardial thickening with enhancement and effusion⁽⁴⁾, discrete pericardial nodules⁽²⁾, pericardial effusion, more often hemorrhagic⁽⁵⁾, masses arising or contiguous with the pericardium⁽⁶⁾. The meticulous radiological investigation is therefore mandatory, an accurate and timely diagnosis having therapeutic consequences.

Materials and method

We made a retrospective study for a period of 10 years (between January 2010 and March 2020), and we selected 101 patients with a hematologic malignancy and CT evidence of a mediastinal tumoral mass, four of them with pericardial and cardiac tumoral extension. All patients underwent CT investigation. CT examinations included one non-enhanced CT phase (NECT), in order to evaluate CT attenuation values of pericardial effusions and calcifications, respectively tumoral mass necrosis, fat, hemorrhage or calcifications, and two contrast-enhanced CT (CECT) in arterial and venous phase, in order to evaluate the tumoral mass, vascular and cardiac structures, and other associated anomalies. Before the CT exam, the allergic history and the serum creatinine level had been checked. The injection ratio was minimum 3 ml/s and the iodinated product was injected in a quantity of 1-1.5 ml/kg b.w. The patients were investigated on 16 or 64 multidetector (MD) CT scanners. The physical parameters used for CT consists in axial thickness slices of 5 mm with 1.25 or 1.5 mm reconstruction interval. CT acquisition was initiated at 25 seconds for the arterial phase and at 80-100 seconds for the venous phase. Different planes reconstructions (coronal, sagittal, oblique views) have been performed in order to have an optimal visualization of the pericardium and vascular structures.

Results

We selected four cases of patients diagnosed with malignant non-Hodgkin lymphoma, with radiological evidence of mediastinal tumors and cardio-pericardial tumoral invasion, three males and one female, with ages between 28 and 62 years old. All patients were investigated with MDCT, computed tomography investigation being able to define the correct extent of the cardio-pericardial tumoral involvement and the vascular permeability. The mediastinal tumors were located in one case in the middle and posterior (Case 1, Figure 1), respectively in the middle and anterior compartment in the second case (Case 2, Figure 2), and in all mediastinal compartments in the other two patients (Case 3, Figure 3). In all cases, CT examination showed bulky, infiltrative mass, with a median axial diameter of 11 cm, one of them with large axis of almost 21 cm, all tumoral masses contiguous with the pericardium. Tumoral invasion of the superior pulmonary veins was identified in two cases. Medium-large pericardial effusion was noted in two cases with mean attenuation values of 10 UH, with slight enhancement of the pericardial layers, but no clinical signs of cardiac tamponade present. Tumoral encasement of the ascending aorta and main pulmonary artery was identified in two cases, in one case with pulmonary artery thrombosis association. Tumoral obstruction of the superior vena cava was present in two cases, in one case with complete obliteration, azygos vein dilatation and collateral vessels in the anterior chest wall.

Discussion

Secondary cardiac and pericardial involvement by lymphoma is more common than primary cardiac lymphoma, at the autopsy being described in almost 18% of patients with non-Hodgkin lymphoma⁽⁷⁾. Retrograde lymphatic, transvenous and contiguous direct extension, as well as hematogenous spread are the main pathways for secondary tumoral cardiac and pericardial involvement^(1,3). CT imaging findings in primary cardiac lymphoma are resembling secondary involvement, typically seen as a bulky cardio-pericardial infiltrative tumoral mass⁽⁸⁾. In our cases, we noted voluminous heterogenous mediastinal mass contiguous with the pericardial layers, with tumoral infiltration of the atrial cavities in three cases (Case 1 and Case 3) and of the pulmonary veins in two cases (Case 1). Intrapericardial tumoral nodular extension of the mediastinal mass was noted in one case (Case 2). Nodular or diffuse pericardial thickening and contiguous tumoral mass with the pericardial structure are considered important CT imaging signs of tumoral pericardial involvement⁽⁹⁾. Also, tumoral obliteration of the superior pulmonary veins represents a reliable sign of intrapericardial tumoral extension⁽¹⁾, presented in two cases (Case 1). CT imaging findings of enlarged mediastinal lymphadenopathies, pericardial nodularity and haematic pericardial effusion are important predictors of malignant pericarditis⁽¹⁰⁾. We found two cases with medium-large pericardial effusion, with mean attenuation value of 10 UH (Case 1 and Case 2). Although in literature the right atrium was mainly involved by lymphomatous tumors⁽⁸⁾, in our patients we found left atrium involvement in three cases (Case 1 and Case 3). Thickening or nodularity of cardio-pericardial structures and intracardiac masses can mimic metastatic cardiac disease⁽¹⁾, but the identification of a tumoral encasement of the mediastinal vessels without evidence of invasion represents a sign of lymphomatous tumoral involvement⁽⁸⁾. In our patients, ascending aorta and the main pulmonary artery tumoral encasement were identified in two cases (Case 2 and Case 3).

Conclusions

CT represents a reliable imaging technique to define the cardio-pericardial tumoral extension of an intrathoracic hematological mass and to assess vascular involvement or thoracic emergency conditions (SVCS, cardiac tamponade or pulmonary embolism).

Conflict of interests: The authors declare no conflict of interests.