Diffuse Myocardial Metastases From Neuroendocrine Malignancy

Figures

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  Figure 1. Admission CT scans and TTE (A) Axial pulmonary artery CTA demonstrates an anterior mediastinal mass of soft tissue attenuation (white arrow) measuring 5.2 x 2.8 x 5.2 cm (AP x TV x CC) at the expected location of the thymus (smaller mass not pictured). (B) Axial CT of the abdomen and pelvis with contrast performed on the same day, zoomed in on the heart, demonstrates diffuse myocardial thickening of the right and left ventricles with heterogeneous enhancement (green arrows). (C) Apical four-chamber view TTE demonstrates moderate to severe right ventricular hypertrophy and severe left ventricular hypertrophy (red arrows). Left ventricular ejection fraction was approximately 20%. Left ventricular myocardium was reported to have a speckled appearance, suggesting a diffuse infiltrative process. CT: computed tomography, TTE: transthoracic echocardiography, CTA: computed tomography angiography, AP: anteroposterior, TV: transverse, CC: craniocaudal.

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  Figure 2. Pathology results from CT-guided mediastinal biopsy and cardiac catheterization myocardial biopsy (A) Insulinoma-associated protein 1 (INSM1) immunohistochemical stain of the cell block material from the mediastinal mass biopsy, demonstrating strong nuclear staining in the tumor cells (400X), indicative of a neuroendocrine tumor (black arrow). (B) INSM1 immunohistochemical stain of cardiac muscle showing strong nuclear staining in the tumor cells (400X), consistent with neuroendocrine metastases (red arrow). CT: computed tomography.

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  Figure 3. Cardiac MRI Short-axis delayed post-contrast phase-sensitive inversion recovery (PSIR) at the (A) basal, (B) mid-cavity, and (C) apical levels. Extensive biventricular myocardial thickening from the base to apex with foci of patchy, nodular, and hazy abnormal delayed myocardial hyperenhancement is present. These findings are demonstrated in the mid cavity right ventricle (blue arrow), septum (white arrow), and left ventricle (green arrow). Similar findings are also visualized in the basal and apical segments.

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  Figure 4. Initial staging DOTATATE PET/CT Images from the pretreatment gallium-68 DOTATATE PET/CT were analyzed, with standardized uptake values (SUV) reported as the maximum values normalized to lean body mass; the mean liver SUV was 4.9. (A) Axial image at the level of the thymus in the anterior mediastinum showing a mass (white arrow) with increased metabolic activity (SUV 17). (B) Slightly inferior, also in the anterior mediastinum, showing an additional mass (green arrow) with increased metabolic activity (SUV 4.3). These anterior mediastinal masses are consistent with neuroendocrine neoplasm. (C) Diffusely increased uptake in the left and right ventricles (blue arrows) (SUV 4.9). A focus of increased metabolic activity in the vertebral body of T9 (orange arrow) (SUV 2.3). PET/CT: positron emission tomography/computed tomography.