Immune-related gigantomastia: a case study

Plain language summaryA person with a type of lung cancer called non-small-cell lung cancer might get treated with a special drug called nivolumab. This drug helps the body's immune system fight the cancer. However, even though these new drugs work well, they can sometimes cause side effects. Some of these side effects are very rare and hard to predict. In one case, a patient who took nivolumab developed a condition called gigantomastia. This means their breasts became unusually large. The doctors checked for other possible causes, but couldn't find any. Gigantomastia is already a very rare condition by itself. What's even more interesting is that nobody has ever reported gigantomastia as a side effect of immunological therapies before. Researchers still don't know why it happened in this case. This episode is worth mentioning because it's a very unusual and unique case. PD-1/PDL-1 inhibitors have revolutionized cancer treatment, especially in lung cancer. Despite their efficacy, a new spectrum of side effects, called immune-related adverse events, may occur and their management could be difficult. Gigantomastia, a rare condition characterized by excessive growth of the breasts, has been associated with some drugs, but no correlation with immunotherapy has ever been reported. Here, we report the case of a possible immune-related gigantomastia.