Case Report A biphasic tumor consisting of pilocytic astrocytoma with an anaplastic solitary fibrous tumor component in the pineal region: A case report and literature review Seon Jung Jang, 1 * Jinna Kim, 2 Jin Mo Cho, 4 SongMi Noh, 1 Sung-Hye Park 3 and Se Hoon Kim 1 Departments of 1 Pathology, 2 Radiology, College of Medicine, Yonsei University, 3 Department of Pathology, College of Medicine, Seoul National University, Seoul, and 4 Department of Neurosurgery, College of Medicine, Ajou University, Suwon, Korea Here we report a case of a biphasic tumor consisting of pilocytic astrocytoma with anaplastic solitary fibrous tumor component in the pineal region. The majority of the tumor showed typical histologic features of pilocytic astro- cytoma. A minor part of the tumor showed marked prolif- eration of short spindle cells around vessels. These spindle cells showed CD34 and CD99 immunoreactivity. From a review of the literature, we found that only one similar case has been reported. Contrary to the reported case, our case showed anaplastic features of solitary fibrous tumor histology. Key words: biphasic tumor, brain tumor, CD34, pilocytic astrocytoma, solitary fibrous tumor. INTRODUCTION Biphasic tumors of the CNS are very rare, and the condi- tion is rarely reported in the literature. According to the 2007 World Health Organization (WHO) classification of tumors, gliosarcoma composed of sarcomatous and malig- nant glial cell elements is now classified as a subtype of glioblastoma. 1 Here we report a unique case composed of low-grade pilocytic astrocytoma intermingled with ana- plastic solitary fibrous tumor component. CLINICAL SUMMARY A 50-year-old woman presented with a 1-month history of headache and blurred vision. She had a history of breast cancer diagnosed 2 years prior to presentation. She had undergone modified radical mastectomy and adjuvant chemoradiation. MRI showed a 3.5 ¥ 3.3 ¥ 2.7 cm contrast- enhancing mass with cystic change in the pineal region (Fig. 1). The radiologic differential diagnosis included metastasis, germ cell tumor and neuroepithelial tumor. She underwent right frontoparietal craniotomy and subtotal tumor removal. This patient received radiotherapy with chemotherapy and was followed very carefully because of the potential for rapid progression or recurrence. During the 14 months of follow-up, there was no evidence of disease progression but in recent follow-up (after 16 months), a solid enhancing lesion in the pineal region was detected by MRI, suggesting recurrence of the tumor. PATHOLOGIC FINDINGS Gross examination revealed a whitish-gray, non-friable soft mass. On microscopic examination, the tumor was com- posed of two distinctive parts (Fig. 2A). The major part, approximately 85% of the total area, consisted of bland- looking glial cells with fibrillary cytoplasmic processes and partly clear cells. Some microcystic changes were seen. On high power examination, the tumor showed scattered eosi- nophilic granular bodies and Rosenthal fibers (Fig. 2B). Focal capillary proliferations were found. There was no definite mitosis.We thought this area was compatible with pilocytic astrocytoma. The minor part, which was approxi- mately 15% of the total area, was not intermingled with the major portion. The minor part showed marked perivascu- lar proliferation of short spindle cells (Fig. 2C).The spindle Correspondence: Se Hoon Kim, MD, Department of Pathology, College of Medicine,Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea. Email: paxco@yuhs.ac and Sung-Hye Park, MD, Department of Pathology, College of Medicine, Seoul National Uni- versity, 103 Daehangno, Jongno-gu, Seoul 110-799, Korea. Email: shparknp@snu.ac.kr Dr. Kim consulted this case to Dr. Park. *Present address: Department of Forensic Science, Korea Univer- sity School of Medicine, Seoul, Korea. Received 12 May 2012; revised and accepted 13 August 2012. Neuropathology 2012; ••, ••–•• doi:10.1111/j.1440-1789.2012.01347.x © 2012 Japanese Society of Neuropathology