Synchronous Melanoma and Pancreas Malignancies Leading to a Discovery of a CDKN2A Mutation in a Patient with No Known Family History.

We report a case of a 60-year-old male with metachronous primary malignancies, pancreatic cancer and malignant melanoma which recurred simultaneously. Both cancers were challenging to diagnose and throughout the case at different times, the presence of two active malignancies obscured the clinical picture. A bleeding gastric lesion found in the stomach 6 months after a distal pancreatectomy for pancreatic adenocarcinoma revealed metastatic melanoma, presumed secondary from a melanoma excised from the patient's back 2 years previously. During surgery intended to resect the gastric lesion, peritoneal nodularity was identified, with histology confirming metastatic pancreas cancer. This case highlights two main points of interest. Firstly it emphasises the role for consideration of a genetic predisposition in young patients with more than one primary malignancy. The man in this case was not informed of his family history as he was adopted. If he had knowledge of previous family history, he may have been able to provide information to expedite arrival at the diagnosis of a CDKN2A mutation (melanoma-pancreatic carcinoma syndrome). In addition, this case also raises the issue of the challenges we face when treating synchronous primary malignancies. The two malignancies here behaved equally aggressively and posed obstacles for treatment as there is no mutual method of carcinogenesis that could be targeted with treatment; therefore, treatment modalities had to be chosen to treat each malignancy separately. To date, studies evaluating the role for targeted therapy in the setting of CDKN2A mutations have not conclusively provided meaningful benefits to patients.