Phosphaturic Mesenchymal Tumors Involving Skull Bones: Report of Two Rare Cases.

Phosphaturic mesenchymal tumor (PMT) is a rare tumor causing oncogenic osteomalacia (OO). Most such tumors occur in soft tissue and bones of extremities and appendicular skeleton. Intracranial location and involvement of temporal-occipital bone is extremely rare. We report two unusual cases: The first was intracranial, involving the temporal bone, while the other was a skull base tumor arising from the occipital-temporal bone. Both of them presented with paraneoplastic syndrome of OO, resembled a meningioma radiologically, and underwent gross total resection of tumor. Histologically, both of them were diagnosed as PMT, mixed connective tissue variant.

Primary paraganglioma of the spine: A clinicopathological study of eight cases.

CONTEXT: Spinal paragangliomas are rare neuroendocrine tumors of the extra-adrenal paraganglionic system. AIMS: This study describes the clinicopathological features of eight cases of spinal paraganglioma and highlights the significance of important morphological features and immunohistochemistry in the diagnosis of paraganglioma at this unusual site. MATERIAL AND METHODS: All the cases of primary spinal paragangliomas diagnosed during the last six years (2008-2013) in the Department of Pathology at our hospital were reviewed. RESULTS: There were six males and two females. The mean age at diagnosis was 50.4 years. All patients presented with low back pain. All tumors were located in the cauda equina or conus medullaris region. Magnetic Resonance Imaging and intraoperative appearance were that of a vascular, well-circumscribed intradural, extramedullary tumor suggestive of either schwannoma or ependymoma. All the patients underwent gross total resection of the tumor. Histopathology in five of the cases showed 'ependymoma-like histology' while only three cases had a predominant classic 'zellballen' pattern. Two cases had prominent 'gangliocytic differentiation'. In the five cases with 'ependymoma-like histology', the diagnosis was confirmed on Immunohistochemistry (IHC). CONCLUSIONS: Even though relatively rare, paraganglioma should be considered in the differential diagnosis of spinal tumors and due to their clinical, radiological and histopathological similarity to schwannoma and ependymoma, the diagnosis should be based on close examination of the clinical, radiological and pathological findings.