Tamoxifen-related porphyria cutanea tarda.

We report a case of porphyria cutanea tarda (PCT) in a patient with breast cancer following adjuvant tamoxifen. Cessation of tamoxifen resulted in a prompt decline in urinary porphyrins suggestive of a causative role. Tamoxifen is known to be hepatotoxic; however, its association with PCT is unclear. In this report, we discuss the porphyrinogenicity of tamoxifen and potential mechanisms.