[Cerebral metastasis of a "ghost" bronchopulmonary tumor]. / Métastase cérébrale d'une tumeur bronchopulmonaire "fantôme".

Carcinoma of unknown primary (CUP) is the metastasis of epithelial malignancy whose origin remains unknown. Bronchial carcinoma is the most common cause (45%), however, in more than a quarter of cases, its origin is unknown and the choice of therapy often justifies a histopathological precision brought by the immuno-histochemistry. We present a rare case of cerebral metastasis, revealing an unknown lung cancer after a comprehensive review. This is a patient aged 53 years, chronic smoker, who presented a year and a half ago a sudden loss of consciousness with afebrile tonic-clonic seizure of spontaneous resolution. Clinical examination was unremarkable. Brain imaging by MRI has objectified the presence of two parietal tissue formations, which stereotactic biopsy with histological and immuno-histochemical favored metastasis of lung adenocarcinoma origin. An etiologic in search of the primitive lung remained negative (chest X-ray of face, chest CT and bronchoscopy with sampling upper gastrointestinal endoscopy). The rest of the etiologic, looking for another primitive, remained negative. The diagnosis of a bronchogenic carcinoma with brain metastasis is therefore withheld. The patient received two brain radiotherapies (gamma kniff) with regression of the two nodular formations. We have not given specific treatment and have called for very close monitoring of the patient who remained stable after 18 months. Through this observation, we stress the interest of the histology and immuno-histochemistry of carcinoma of unknown primary (CUP) to the diagnosis, guide therapy and determine prognosis.