Exuberant local tissue reaction to intramuscular injection of nandrolone decanoate (Deca-Durabolin)--a steroid compound in a sesame seed oil base--mimicking soft tissue malignant tumors: a case report and review of the literature.

We present an unusual pseudotumor that formed in reaction to self-administered intramuscular injections of an anabolic steroid, nandrolone decanoate (Deca-Durabolin) in a young soldier. The histopathologic features which closely mimicked several malignant neoplasms could have led to an incorrect diagnosis of malignancy and unnecessary extensive surgery. To our knowledge, this phenomenon has not been previously reported.