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

Abstract

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.

Keywords: Cauda equina; ependymoma-like histology; paraganglioma; spinal.

Figure 1

Magnetic resonance imaging scan of lumbosacral spine sagittal sections show on (a) T1-weighted; well-defined isointense intradural extramedullary lesion at L2-L3 level, (b) T2-weighted; the lesion becoming hyperintense, (c) strong homogenous enhancement of the tumor on gadolinium administration

Figure 2

(a and b) Well-encapsulated and vascular tumor (a: H and E, ×100; b: H and E, ×200)

Figure 3

(a and b) Well-formed perivascular pseudorosettes. They closely resemble the pseudorosettes of ependymoma (a: H and E, ×200; b: H and E, ×400)

Figure 4

(a and b) Elongate papillae lined by columnar cells. This pattern noted predominantly in one and focally in three tumors, may be confused with papillary ependymoma (H and E, ×200)

Figure 5

Ganglionic differentiation (H and E, ×600)

Figure 6

Prominent perivascular hyalinization was not uncommon (H and E, ×200)

Figure 7

(a-c) Immunohistochemically, the neoplastic cells expressed synaptophysin, chromogranin and nonspecific enolase (NSE), diffusely and strongly (a: synaptophysin immunostaining, ×400, b: chromogranin A immunostaining, ×400, c: NSE immunostaining, ×400). (d) By S100 immunostaining, scattered S100 protein immunoreactive sustentacular cells were evident (S100 protein immunostaining, ×400). (e) The tumor cells were immunonegative for glial fibrillary acid protein (GFAP) (GFAP immunostaining, ×200)