[A Case of Suprasellar Germinoma that Spontaneously Regressed before Endoscopic Biopsy].

We present a very rare case of suprasellar germinoma that spontaneously regressed before endoscopic biopsy. An 8-year-old boy was admitted to our hospital due to headache, polydipsia, and polyuria. Neurological examination performed on admission revealed bitemporal hemianopia. Enhanced MRI demonstrated a homogeneously enhanced tumor mass in the suprasellar region obstructing the foramen of Monro. Tests for all serum tumor markers were negative. Plain X-ray and CT scan were performed once and twice, respectively, for seven days between admission and endoscopic biopsy. The total dose of diagnostic radiation exposure before surgery was 110 mGy. Endoscopic observation during surgery revealed that the tumor had markedly decreased in size and the foramen of Monro had reopened. A very small piece of the tumor was harvested during surgery. Plain CT scan just after surgery showed a marked decrease in the tumor size, compared with the preoperative CT scan. The pathological diagnosis of the tumor was pure germinoma. The patient then underwent chemotherapy(four courses of CARE regimen)followed by radiation therapy with a dose of 24 Gy/15 fr. The tumor completely disappeared after treatment, and no recurrence was observed in the past four years.