November 2002: a 72-year-old woman with a pineal gland mass

The November 2002 COM. A 72-year-old immunocompetent woman presented with recent confusion, memory loss, visual and a gait disturbance. MRI scans demonstrated a T2 hypointense, gadolinium enhancing mass in her pineal region. A whole body CT scan identified a large retroperitoneal mass and significant lymphadenopathy. She underwent a biopsy of the pineal lesion. The intraoperative smear contained discohesive, basophilic malignant cells of moderate size that had only scant cytoplasm, an increased nuclear-to-cytoplasmic ratio and irregular, hyperchromatic nuclei containing prominent nucleoli. Mitotic figures, apoptotic and lymphoglandular bodies were frequent. Histologic examination showed malignant cells infiltrating and almost completely replacing the residual pineal gland. The tumor cells immunoreacted with LCA and CD-20. Scattered CD3 and UCHL-1 positive cells were also present. The diagnosis was stage IV, high grade, large B-cell lymphoma involving the pineal gland and retroperitoneum. Four cycles of systemic chemotherapy significantly reduced the patient's retroperitoneal mass. However, a repeat head MRI scan continued to show gadolinium-enhancement in the pineal region, now with extension into contiguous brain parenchyma and the subependymal region. The patient died 4 months after presentation. At autopsy, the lymphoma encased the pineal region and disseminated along the ventricular walls and into the subarachnoid spread. Pineal-region tumors are rare in the elderly population, and although unusual, lymphomas should be considered in this context. The behavior of this circumventricular organ lymphoma was comparable to both peripheral and primary central nervous system lymphomas.