Papillary glioneuronal tumors: A radiopathologic correlation

Objective: Papillary glioneuronal tumors (PGNT) are a rare and recently recognized tumor entity. The neuro-imaging findings were reviewed to determine if any specific findings emerge to assist a preoperative diagnosis of PGNT. Materials and methods: Seven histologically confirmed cases of PGNT were evaluated from 2004 to 2014. Clinical, neuroimaging and histological findings were reviewed and tabulated. Results: Headache and seizures were observed in 4 patients (57.1%) each. The majority (n = 5, 71.4%) of lesions were periventricular and located in temporal lobe with 57.1% cases being solid cystic (n = 4), and 42.9% being purely solid (n = 3). Calcification and hemorrhage were noted in 3 cases (42.9%) and 5 cases (71.4%) respectively. The most frequent imaging feature was the presence of septations in the cystic component that enhanced on contrast which correlated with long pseudopapillary projections into the cyst cavity on histopathology. The solid inner component demonstrated heterogeneous enhancement. One case with tumor recurrence demonstrated hemorrhage with superficial siderosis, patchy diffusion restriction, raised choline and focal areas of raised perfusion which correlated on histopathology with increased cellularity and anaplasia. Conclusion: Presence of cystic mass in periventricular location with septations and a solid inner component should raise a suspicion of PGNT on neuroimaging.