Melanoma metastasis to the pancreas with interesting MRI findings: A case report

Abstract

A woman in her 60s was admitted with jaundice. She had a history of resection of a melanotic melanoma in the right paranasal sinus about six months previously. On admission, abdominal CT scan revealed lesions up to 25 mm in the head and body of the pancreas. Those lesions were hypointense on MRI T1-weighted images. This finding was not typical of melanotic melanoma. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed, and a diagnosis of pancreatic metastasis from melanoma confirmed by immunostaining. In this patient, the primary lesion was melanotic but the biopsy specimen from the metastatic lesion contained few melanin granules, which may explain why the pancreatic lesions had such MRI findings. The specimen was evaluated for genetic mutations using the primary lesion in order to select the best therapeutic agent, because there was insufficient tissue from the pancreatic metastasis. The selected drug had little effect, which suggests that the metastatic lesions had a different genetic character than the primary lesion.