A teratocarcinoma developing after gross total excision of a pineal teratoma in a patient with systemic lupus erythematosus.

This is a rare case of a teratocarcinoma developing at the same site one year after the gross total excision of a mature pineal teratoma. The malignant tumour arose probably from microscopic remnants of the teratoma. This patient also suffered from systemic lupus erythematosus. Autoimmune diseases have been associated with an increased risk of malignancy, and in this case may have contributed to the malignant transformation of the teratoma.