Cardiac Metastasis of Malignant Melanoma Detected by 18F-FDG PET/CT

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  Figure 1. A 61-year-old man was recently diagnosed with cutaneous melanoma in the right planta (Breslow thickness 2 mm). The patient had no family history of malignancy. Preoperative 18F-FDG PET/CT did not show any nodal or distant metastasis. He then underwent enlarged excision of the tumor and sentinel lymph-node biopsy, and his tumor was staged T3bN0M0 (IIb). He did not receive adjuvant treatment and was closely followed postoperatively. Nineteen months after surgery, he presented with blood-stained sputum and CT revealed multiple masses and nodules in bilateral lungs, which were confirmed to be pulmonary metastases from malignant melanoma after biopsy. The immunohistochemical results were AE1/AE3 (−), HMB45 (+), Melan-A (+), Ki-67 (index 50%), TTF-1 (−), S-100 (+). The follow-up 18F-FDG PET/CT ((A) PET MIP, (B) axial PET, (C) coregistered CT, (D) fusion image) showed multiple hypermetabolic masses in bilateral lungs (arrows, SUVmax 10.6), consistent with pulmonary metastases. Bone metastasis in the right ilium was also detected ((E)–(G), dotted arrows, SUVmax 3.1). His left ventricular myocardium exhibited diffuse uptake, which was physiological (Figure 1). Notably, a nodular…

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  Figure 2. Dynamic myocardial perfusion MRI ((A) T1WI, (B) T2WI, (C) delayed scan of enhanced T1WI) also detected the lesion in the left ventricular lateral wall with a short T1 signal and a long T2 signal intensity with delayed enhancement (Figure 2, arrows). Subsequent gene testing revealed an insertion mutation in exon 11 of the KIT gene and no BRAF mutations were detected. Considering the advanced stage of malignant melanoma, he was treated with imatinib and received radiotherapy of the largest mass in the right lung. However, the treatment of imatinib was discontinued 6 weeks later because of a drug reaction with eosinophilia and systemic symptoms (DRESS). The patient experienced rapid progression of the tumor 4 months thereafter and died of the disease.