Metastatic Intracranial Choriocarcinoma in the Absence of a Primary Lesion: A Case Report.

Intracranial choriocarcinoma is a rare and aggressive neoplasm characterized by the proliferation of trophoblastic tissue. Although choriocarcinoma most commonly arises in the uterus as a component of gestational trophoblastic neoplasia, instances of intracranial choriocarcinoma are exceptionally uncommon. We report a case of intracranial choriocarcinoma without any evidence of a tumor elsewhere. A 25-year-old woman presented with a history of 1 month of evolution with right frontal hemicranial headache, followed by visual disturbances, otalgia, and diplopia. On neurological examination, she was conscious, cooperative, and well-oriented; a grade 1 bilateral papilledema, left homonymous hemianopsia, and sixth cranial nerve paresis, with diplopia, were detected. Neuroimaging showed a right parieto-occipital lesion with features mimicking an atypical meningioma. After surgical resection, a diagnosis of choriocarcinoma was issued. Primary intracranial choriocarcinomas are typically located in the sellar and pineal regions. The occurrence of this tumor within the occipital lobe suggested metastasis; however, a primary tumor in the thoracic or abdominal organs was not observed and a delayed metastasis was considered. This case highlights the diagnostic challenges associated with intracranial choriocarcinoma.