Breast tumor developed in a pregnant rat after treatment with the teratogen Cycloheximide.

Aim: To describe histochemically and immunohistochemically a breast tumor presented in a pregnant rat given Cycloheximide to examine its teratogenic and embryotoxic effect on the embryos.

Methods: Cycloheximide was injected in pregnant Wistar rats at a dose of 3 mg/kg.b.