Contributed by Yuen Shan Wong1, Anthony Wing-Hung Chan2, Ho Keung Ng1,2, Danny Tat-Ming Chan1
Daniel Wing-kit Ng1, Deyond Yung-woon Siu1,3, Peggy Tang3, Wai-Sang Poon1
Chinese University of Hong Kong Brain Tumor Centre, Department of Surgery1, Department of Anatomical and Cellular Pathology2
Department of Radiological Imaging3, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China
A 45-year-old man presented to us with headache and vomiting for15 years ago. He was diagnosed as having obstructive hydrocephalus due to a pineal region tumour. A ventriculoperitoneal shunt was inserted to relieve hydrocephalus with symptomatic relief. He was followed up with regular MRI scans. Serial imaging showed slow progression in tumor size when he was 60 years old. Neurological examination revealed Parinaud sign with upward gaze palsy. The MRI with gadolinium showed an mildly enhancing lobulated tumor in the region of the superior tectum measuring 22.5mm x 21mm x 20mm (Figs. 1 and 2). The lesion at the superior tectum and the pineal region showed heterogeneous T1-hyperintense signal on precontrast images (Fig. 1). It exhibited very slow growth, with a gradual increase in size over 15 years. There was mild mass effect to the cerebral aqueduct with indentation of the pineal gland (Fig. 3). However, there was no hydrocephalus at that time. In view of symptomatic progression of tumor size, he underwent a near total tumour excision via infratentorial supracerebellar approach.
Histological examination showed a cellular epithelioid papillary tumour. The papillae were closely-packed and covered by layers of large polygonal columnar cells with oval nuclei, fine stippled chromatin, and moderate amount of clear, vacuolated or pale eosinophilic cytoplasm (Figs. 4 and 5). Mitosis, tumor necrosis or microvascular proliferation was lacking. Immunohistochemical stains revealed diffuse positivity for pan-cytokeratin (AE1/AE3; Fig. 6); and focal patchy positivity for epithelial membrane antigen (EMA) and neuroendocrine marker (synaptophysin; Fig. 7) GFAP, thyroid transcriptional factor-1 (TTF-1), thyroglobulin, intestinal marker (CDX-2) and prostate specific antigen (PSA) were all negative. Proliferation index (Ki67) by immunostaining for MIB-1 was estimated to be about 7%.