Most cutaneous adverse drug reactions reported in association with chemotherapy, such as a limited maculopapular rash, are considered mild and do not affect the continuation of the treatment. Toxic epidermal necrolysis (TEN), however, is a life-threatening reaction that needs treatment discontinuation. The present case shows the slow progression from a pemetrexed and carboplatin-associated maculopapular rash to a TEN-like reaction.