A rare giant mixed germ cell tumor of the pineal region with immature elements: Case report and review of the literature.

The diagnosis and management of mixed intracranial germ cell tumors may be complicated by the diversity present within this tumor category. Mixed germ cell tumors demonstrate variable natural histories which may be altered by the inclusion of even the most minute immature histological components. We report the case of an 18-year-old male who presented with a 3-month history of progressive headache and nausea leading to lethargy. Imaging revealed a giant pineal region mass extending superiorly from the roof of the fourth ventricle into the lateral ventricle, with resultant obstructive hydrocephalus. No spinal lesions were noted. Following gross total resection, the patient experienced marked improvement. Pathologic analysis identified an uncommon tumor composition: mature teratoma (96%), immature teratoma (2%), and germinoma (2%). Guided by the immature component, chemotherapy and radiation were added post-operatively to provide this patient with the greatest chance of long-term survival. Intracranial pathology, including germ cell tumors, should be included in the differential for any young patient presenting with new and progressive headache and nausea. This case emphasizes the benefit of a multimodal approach to mixed germ cell tumors of the pineal region and the importance of careful pathologic review of all submitted material.

Solitary Fibrous Tumor of Pancreas With Unusual Features: A Case Report.

Solitary fibrous tumor (SFT) is an uncommon fibroblastic neoplasm that is most commonly associated with the pleura but has also been reported in almost all anatomic sites. Although the majority of SFTs are benign, few cases follow a malignant clinical course and may recur and/or metastasize after several years of their original occurrence. Only 16 cases of pancreatic SFTs are reported so far, and only one has metastasized to lung and subcutis. Pancreatic SFT resembles more common neuroendocrine tumor and gastrointestinal stromal tumor (GIST) radiographically and is at times almost indistinguishable from GIST histologically. Diagnosis of SFTs particularly, if attempted on biopsied specimens, can be very challenging due to its rare occurrence and nondescript morphology. It is imperative to understand the pathological spectrum of this entity to avoid misdiagnosis. We report a case of pancreatic SFT in a 43-year-old male with some unusual morphologic and immunohistochemical features including pseudoangiomatous growth pattern, a hypercellular area demonstrating nuclear pleomorphism, and only focal positivity for cluster of differentiation (CD)34. These atypical features can pose even more diagnostic challenge by causing additional confusion with other malignancies like dedifferentiated liposarcoma and vascular tumors. The potential diagnostic pitfalls are discussed.