ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 prognostic difference in this small group of cases; TERT promoter mutation and homozygous deletion of CDKN2A and/or CDKN2B become more needed to foresee the disease progression. E-PS-17-019 Low-grade glioneuronal tumour with neuropil-like islands and FGFR1 mutation, a case report A. Maswadeh, H. Sultan, B. Maraqa, M. Al-Hussaini* *King Hussien Cancer Center, Jordan Background & objectives: Glioneuronal tumour with neuropil-like islands (GNTI) is a rare tumour entity that is described mainly in adults with very few cases reported in pediatrics that are molecularly tested. Methods: An 8-year-old female presented initially in 2016, at the age of 1-year, with seizures and was found to have a left frontal mass, for which she underwent craniotomy. In 2018, she presented with recurrence and in 2021 she presented with a second recurrence. No chemotherapy or radiotherapy was administered. Results: A review of the original pathology material as well as of the first and second recurrence shows similar features. There is proliferation of monotonous round cells with clear cytoplasm, sepa- rated focally by fine vasculature and in other foci by proliferating vessels, with occasional mitotic figures. These foci are positive pri- marily for GFAP. Other foci show islands of neuropil surrounded by cells with clear cytoplasm that stained for Synaptophysin and focally for NeuN. The final diagnosis was a low-grade glioneuronal tumour with neuropil-like islands. Examination by Nanostring confirmed the presence of FGFR1 tyrosine kinase domain duplication (TKDD). Conclusion: FGFR1 TKDD is known to be implicated in paediatric low-grade glioneuronal tumours, including DNET. Glioneuronal tumour with neuropil-like islands is another morphological varia- tion along the spectrum of tumours characterized by FGFR1 muta- tions. This has important implications for confirmation of the diag- nosis as well as being predictive of response to FGFR inhibitors. E-PS-17-020 Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease): a rare case report Z. Lajmi*, A. Bdioui, M. Krifa, W. Majdoub, A. Baccouche, S. Hmissa *Department of Pathology, Farhat Hached University Hospital, Tunisia Background & objectives: Dysplastic gangliocytoma of the cerebel- lum (DFG), also called Lhermitte-Duclos Disease, is a rare lesion of the posterior fossa consisting of a diffuse hypertrophy of the cerebellar cortex. It is one of neuronal and mixed neuronal-glial tumour, WHO grade I disease. Methods: A 26-year-old man, with no history, consulted for a pro- gressive vertigo and headache, with nausea and vomiting for 7 days. During the physical examination, the vital signs were stable. The patient displayed ataxia with wide-based gait. No nystagmus. Brain MRI showed an intra-parenchymal lesion of the left cerebel- lum, isointense on T1- and T2-weighted sequences. No prominent enhancement. Results: Surgical resection was proposed because of size, the unde- termined nature of the lesion and the supposed impact on expansion of the cerebellum. The patient underwent tumour resection. The histopathological examination showed an abnormal architecture of the cerebellar cortex: dysplastic Purkinje cells were present in the granular layer and in the underlying white matter. The molecular layer was replaced by larges axon bundles. No mitosis or necrosis was be seen. Ectatic vessels and calcifications were present. Ki67 was inferior to 1%. In immunohistochemistry, dysplastic cells were synaptophysin and GFAP positive. The diagnosis of a dysplastic gangliocytoma of the cerebellum was confirmed. Conclusion: DGC is a rare and benign brain tumour. It has both neoplastic and hamartomatous characteristics. It frequently pre- sents in young adults. The pre-operative diagnosis proves to be a challenge. On MR, Tiger-strip sign is characteristic but is not always seen. The prognosis is good if total resection can be achieved. Further molecular examinations of PTEN gene mutation is recommended. Adult-onset of DGC is considered to be a pathog- nomonic criteria of Cowden syndrome characterised by mutation of PTEN gene. E-PS-17-021 Cerebellar liponeurocytoma: clinical and pathological analysis M. Alaya*, B. Chelly, A. Ayari, H. Azouz, A. Zehani, I. Chelly, K. Bellil, S. Haouet *Department of Pathology, La Rabta Hospital, Tunis, Tunisia Background & objectives: Liponeurocytomas are rare and slow- growing tumours located predominantly in the cerebellum. Our aim is to present a new case of liponeurocytoma and describe its epide- miological, clinical and pathological features, as well as management strategies. Methods: We describe a new case of liponeurocytoma diagnosed in the Rabta hospital, Tunis, Tunisia. Results: We report the case of a 38-year-old woman without par- ticular pathological antecedent with a few months history of head- ache and dizziness, aggravated since 2 days by signs of increased intracranial pressure and cerebellar dysfunction. The Computerized Tomography practiced in emergency showed a subtentorial space occupying mass, heterogeneous, exhibiting the attenuation values of fatty tissue, with hydrocephalous upstream. The patient has been operated. The histopathological and immunohistochemical studies concluded a cerebellar liponeurocytoma. Conclusion: Cerebellar liponeurocytoma is a rare neoplasm with distinctive morphologic features. It typically involves the cerebellar hemispheres of middle-aged to older adults. The tumour is com- posed of a uniform population of neurocytic cells possessing round to oval nuclei and pale to clear cytoplasm. A variable degree of lipidization of the tumour cells is present, lending a resemblance to mature adipose tissue. E-PS-17-022 Atypical presentation and no concordant methylation class of a paediatric high-grade astrocytoma with piloid features (HGAP) T. Sanhueza Alzamora*, M. Suñol, C. Rovira, S. Planas, A. Zuc- chiatti, C. Lavarino, M. Pavon, O. Cruz, M. Rebollo, J. Hinojosa, C. Jou *Hospital Sant Joan de Déu, Spain Background & objectives: High-grade astrocytoma with piloid fea- tures (HGAP) is an uncommon new tumour entity of the central nerv- ous system, extremely rare in paediatric population. Characterized by distinct DNA methylation profile, CDKN2A/B deletion, MAPK path- way alterations and ATRX mutation and/or loss of expression. Methods: We describe the case of a 7-year-old boy with no rel- evant medical history, admitted in our hospital due to a raised intracranial pressure, secondary to hydrocephalous. Cerebral magnetic resonance imaging revealed a hypothalamic-optical S319