Context: Insulinomas may be regarded as potentially malignant. A long follow-up period is needed to detect any possible recurrence, even if the initial diagnosis was of a benign insulinoma.
Case report: We present the case of a 76-year-old woman with liver metastases due to a malignant insulinoma, which had been diagnosed as benign after its complete removal 9 years earlier.
Conclusions: This case shows the difficulty of distinguishing between benign and malignant insulinomas when there is no initial evidence of metastases. This fact poses the need to conduct a long follow-up period in order to detect any possible recurrence even if the initial diagnosis was one of a benign insulinoma.