Solitary cystic brain metastasis of small-cell lung carcinoma controlled by a stereotactically inserted Ommaya reservoir.

Brain metastases are quite common during the management of lung carcinomas. Most are solid masses with necrosis and surrounding edema, whereas purely cystic lesions are uncommon and malignant cells creating the wall are usually resistant to radiotherapy, sometimes requiring neurosurgical strategies. Cystic brain metastases from small-cell lung carcinomas are exceedingly rare and neurosurgical operations are not suitable for those cases considering invisible micrometastases. A 34-year-old female patient presented with small-cell lung carcinoma that metastasized to the brain as a solitary cyst with a thin wall 24 months after a good partial response to initial chemoradiotherapy. The brain mass volume and the main symptom of left hemiplegia, which made the Karnofsky performance status (KPS) fall to 30%, did not respond to whole brain irradiation. Therefore, an Ommaya reservoir was inserted, which dramatically improved the KPS to 70%. This minimally invasive surgical strategy is suitable even for patients with a poorer KPS bearing cystic brain metastases.