A fatal primary gastric melanoma treated by a double immunotherapy with ipilimumab/nivolumab: description of a case report.

Background: Primary gastric melanoma (GM) is a very uncommon tumor with a poor prognosis. Until now, only a few cases have been reported in the literature. Case Description: A 70-year-old, Caucasian, ex-smoker man, presented with asthenia, anorexia, and weight loss of 5 kg during the last 2 months. Biological test showed high levels of transaminases and a microcytic, hypochromic anemia. Whole body CT-scan documented a gastric tumor lesion with concomitant loco-regional lymph node and hepatic metastases. Histology was consisted with the diagnosis of a primary GM. A double immunotherapy with nivolumab and ipilimumab was started but, 2 weeks later, the patient presented an acute hepatic failure quickly leading to his death despite a high dose corticotherapy. Conclusions: The particularity of this case relies on the rarity of GM, its difficult diagnosis representing a clinical challenge, and the complexity of its management that is not validated by large clinical trials, data being extrapolated from the treatment protocols routinely used in cutaneous melanoma. In our case, the patient died 2 weeks after the first cycle of a nivolumab/ipilimumab combined treatment for an acute hepatic failure that could be related to a treatment toxicity or a tumor hyperprogression. The patient's survival was very short not allowing any accurate evaluation of the efficacy of this therapy.