Papillary glioneuronal tumors are rare well circumscribed complex solid cystic supratentorial lesion with an indolent clinical course.
These tumors typically are diagnosed in younger patients (median age at diagnosis 23 years) but are reported essentially in all ages 4. No sex predilection has been identified 4.
Clinical presentation is non-specific, primarily comprising seizures and/or headaches. Focal neurological deficits may also be present.
Papillary glioneuronal tumors were first recognized in the 2007 edition of the WHO classification of CNS tumors and are considered WHO grade I tumors.
The majority of these tumors are in the cerebral hemispheres, with occasional intraventricular tumors described 4.
These tumors usually demonstrate a mixture of solid and cystic components, sometimes with calcification 4.
Papillary glioneuronal tumors contain both glial (astrocytic) and neural elements. Characteristic microscopic features are hyalinized vascular pseudopapillary architecture with a pseudostratified layer of cuboidal glial cells and focal collections of neurocytes and ganglion cells.
Immunohistochemistry of the cuboidal glial cells reflects their glial appearance 4:
In contrast, the neuronal components show a separate immunophenotype 4:
These tumors demonstrate a low Ki-67 proliferation index/MIB-1 index ~1-2% 1-4. Rarely, tumors with higher mitotic index are encountered and some have more aggressive behavior 4.
Features on imaging are very similar to ganglioglioma. They are supratentorial solid-cystic or cystic with solid nodule lesions showing intense but heterogeneous enhancement. Calcification is a frequent finding 1-4. Hemorrhage is seen in ~10% of cases and is sometimes very pronounced 4.
- T1: isointense to hypointense
- T2: inhomogeneously hyperintense
- inhomogeneously hyperintense nodule
- cystic components may suppress
- T1 C+: avid but heterogeneous enhancement of the solid nodule
Treatment and prognosis
Papillary glioneuronal tumors are indolent and surgical resection is usually sufficient to effect a cure. In cases where proliferation is high (e.g. Ki-67 >5%) then local recurrence has been described 4.
The differential diagnosis is primarily of other parenchymal tumors with mixed solid and cystic components, including:
- 1. Stosic-Opincal T, Peric V, Gavrilovic S et-al. Papillary glioneuronal tumor. AJR Am J Roentgenol. 2005;185 (1): 265-7. doi:10.2214/ajr.185.1.01850265 - Pubmed citation
- 2. Govindan A, Mahadevan A, Bhat DI et-al. Papillary glioneuronal tumor-evidence of stem cell origin with biphenotypic differentiation. J. Neurooncol. 2009;95 (1): 71-80. doi:10.1007/s11060-009-9893-5 - Pubmed citation
- 3. Guo SP, Zhang F, Li QL et-al. Papillary glioneuronal tumor-contribution to a new tumor entity and literature review. Clin. Neuropathol. 2008;27 (2): 72-7. Pubmed citation
- 4. Louis DN, Ohgaki H, Wiestler OD, Cavenee WK "WHO Classification of Tumours of the Central Nervous System. 4th Edition Revised" ISBN: 9789283244929