Pediatric Hematology and Oncology, 25:5–15, 2008 ISSN: 0888-0018 print / 1521-0669 online DOI: 10.1080/08880010701665777 MRI CHANGES IN THE “NORMAL” PINEAL GLAND FOLLOWING CHEMOTHERAPY FOR SUPRASELLAR GERM CELL TUMORS Shannon M. MacDonald ✷ Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA Neal Desai and Gordon Heller ✷ Department of Radiology, Beth Israel Medical Center, New York, New York, USA Linda Rolnitzky and Jeffrey C. Allen ✷ Departments of Pediatrics, Neurology, and Biostatistics, New York University, New York University Medical School, New York, New York, USA ✷ Primary CNS germ cell tumors (GCT) arise in the suprasellar and pineal regions. Suprasellar GCT may remain radiographically occult during the early symptomatic period. Although theoreti- cally possible, it is more difficult to identify presymptomatic disease in the pineal region. Given the sensitivity of GCT to cytotoxic therapy, a decrease in size of the “normal” pineal gland following chemotherapy (CHT) could divulge preexisting disease. Such information may impact radiation treatment (RT). The authors reviewed MRIs of 15 patients with suprasellar GCT treated with pre-RT CHT. They defined a ≥50% reduction in volume of the pineal gland as a substantial decrease suspicious for preexisting occult disease. As controls, MRIs of 11 medulloblastoma patients who received cytotoxic therapy were reviewed. Pineal gland volumes could be determined for 12 of 15 patients with GCT and 7 of 11 patients with medulloblastoma. The study radiologists concurred that 2/12 GCT patients and 0/7 medulloblastoma patients had ≥50% volumetric reduction. When radiation is delivered as the sole treatment modality, the pineal region is included in at least the initial volume, but in certain clinical trials RT volume is reduced to only the suprasellar region if a complete response is achieved following pre-RT CHT. Noting changes in the “normal” pineal gland following CHT may indicate disease. CHT alone may not be sufficient to control this disease, even in cases in which a complete response is achieved. If the intent is to deliver RT to all areas of initial disease and this phenomenon can be demonstrated on a larger scale, inclusion of the pineal should be considered for patients demonstrating a substantial decrease in the size of the pineal gland after CHT. Keywords germinoma, magnetic resonance imaging, occult disease, pineal gland Received 29 March 2007; accepted 10 August 2007. This article is not subject to United States Copyright laws. Address correspondence to Jeffrey C. Allen, MD, NYU Medical Center Hassenfeld Clinic, 160 East 32nd St, New York, NY 10016, USA. E-mail: jeffrey.allen@NYUMC.org 5