Successful Treatment by Chemotherapy of Pineal Parenchymal Tumor with Intermediate Differentiation: A Case Report
A 37-year-old male visited a clinic due to a headache and dizziness in December 2010. There was no distinguishable observation in his past history, physical examination, and laboratory tests. In addition, the head-up-tilt-table test and video eyeball exam showed no obvious abnormalities. Computed tomography (CT) of his brain was performed and a mass measuring 2.5 cm in size was observed in the midbrain and obstructive hydrocephalus. The tumor showed intermediate enhancement in T1-weighted magnetic resonance (MR) imaging and a high intensity of enhancement in T2-weighted MR (). Differential diagnosis based on MR imaging included germinoma, PPT, and glial tumor. Neurosurgeons performed an immediate occipital craniotomy and partial removal of the tumor in 2010. Histological diagnosis concluded that the mass was a PPT with intermediate differentiation. The majority of the tumor tissue consisted of small hyperchromatic cells with moderately increased cellularity and a high nuclear to cytoplasmic ratio. The tumor cells showed some atypical mitosis but rarely exhibited mitotic activity. A clear Homer Wright rosette, many of which have been termed "pineocytomatous resettes" was not found (). Diffuse staining for neuron specific enolase and focal staining for synaptophysin were observed, while the immunohistochemistry analysis showed very little glial fibrillary acidic protein (GFAP) staining. Such a focal staining pattern of synaptophysin staining in the pineal region neoplasm, coupled with the lack of GFAP staining was most consistent with a PPT ().\nHe underwent irradiation with 54 Gy of radiation on 27 fractions for removal of the remaining tumor for approximately one month after surgery. However, a remnant mass in the superoposterior aspect of the midbrain had extended to the hypothalamus and the third ventricle approximately five months after the operation. MR imaging showed leptomeningeal enhancement in the infratentorial fossa, indicating tumor cell seeding. (). He was referred to the department of medical oncology for palliative chemotherapy and was treated with a procarbazine, lomustine, vincristine (PCV) regimen one month later. The size of the remaining tumor in the midbrain and the leptomeningeal enhancement was reduced in the follow-up brain MR imaging. Two months later, after the sixth cycle of PCV chemotherapy, no evidence of the tumor was observed in the brain MR imaging (). No additional signs of a tumor were observed in the latest follow-up imaging, which was performed approximately 20 months after the initial diagnosis. The patient was free of any signs of recurrence without any neurological deficits six months after the end of treatment.