Composite cerebral metastasis and oligodendroglioma: an exceptional form of mixed neoplasia.

Our report describes the uncommon case of a 61 year old female patient who underwent a left parietooccipital craniotomy and extirpation of a malignant tumor. Histological examination revealed a metastatic carcinoma of mammary origin intimately intermingled with a calcified oligodendroglioma WHO II. The preexisting oligodendroglial part had been detected four years before, but since then had been misinterpreted as a glious scar resulting from a previous brain trauma. Three years before neurosurgical intervention, the patient had undergone a left side mastectomy. The histological finding at that time was a solid breast tumor WHO T1N0. The occurrence of cerebral mixed neoplasias and possible causal factors are discussed.