Pineal parenchymal tumors of intermediate differentiation in adults: case report and literature review.

Pineal parenchymal tumors (PPT), including pineoblastomas, are very uncommon, especially in adults. Because of the small number of reported cases, the histological and biological features of these tumors are still being defined, as is their optimal management. Also, the pathological variability of these tumors makes it difficult to draw general conclusions about their behavior. We report the case of a PPT of intermediate differentiation (PPTID) with an excellent outcome. A 3.2 cm tumor in the pineal and tectal region with obstructive hydrocephalus was found in a 28-year-old female complaining of headaches and hypoesthesia of the right side of the face. Stereotactic biopsy revealed a highly cellular tumor composed of small cells that contained little cytoplasm that were arranged in a diffuse pattern. Mitotic activity was low and there was no evidence of necrosis. Immunohistochemical examination demonstrated positive staining for neuron-specific enolase and synaptophysin. There was no expression of neurofilaments or GFAP. Ki-67 proliferation index was 12%. The diagnosis was a PPTID. Treatment consisted of combined neoadjuvant chemotherapy and craniospinal radiotherapy. Six years after treatment, the patient is alive and free of any clinical or radiological signs of relapse. This paper discusses the pathological and biological features of these tumors and the treatment options available.