ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Background & objectives: We investigated the expression and dis- tribution of SOX-2-positive and CD133-positive cancer stem cells both in the enhancing nodule (EN) and in the FLAIR hyperintensity zones on a surgical, histopathological series of 33 glioblastomas (GBMs). Methods: The inclusion criterion was the intraoperative sampling of different tumour regions by Neuronavigation and positivity to intraoperative 5-ALA fluorescence. 33 patients (20 males and 13 females with a mean age at diagnosis of 56 years) met the inclusion criterion. A total of 109 histological samples were evaluated, 52 for ENs and 57 for FLAIR hyperintensity zone. Results: Considering the quantitative distribution of levels of intensity of staining (IS), ES (extent score) and immunoreactiv- ity score (IRS), no difference was found between ENs and FLAIR regions for both the SOX-2 biomarker (respectively, IS p=0.851, ES p=0.561, IRS p=1.000) and the CD133 biomarker (IS p=0.653, ES p=0.409, IRS p=0.881). Conclusion: This evidence suggests to recalibrate the target of surgery for FLAIRECTOMY and 5-ALA could improve the pos- sibility to achieve this goal. E-PS-17-006 Frontal intraosseous leiomyoma: an unusual case in a 15-months infant N. Mansouri*, M. Ben Thayer, F. Gargouri, R. Aouadi, K. Tlili, I. Msakni, B. Laabidi *Department of Pathology, Military Hospital of Tunis, Tunisia Background & objectives: Leiomyomas are benign tumours arising from smooth muscle cells. Intraosseous occurrence of leiomyoma is extremely rare with less than 35 cases reported in the literature. Throught this case report, we aim to discuss clinicopathological aspects of this entity. Methods: We present a case of frontal intraosseous leiomyoma (IL) occurring in a15-mounths infant. Results: A 15-month-old female infant presented with an undwell- ing lump on the forehead. Clinical examination revealed a well defined and firm swelling over the forehead. Plain radiography showed a well-defined osteolytic lesion. Histologically, the tumour was localized in the spongious bone. It was composed of moder- ately cellular spindle cells arranged in orderly intersecting fasci- cles, with abundant eosinophilic cytoplasm and elongated blunt ended “cigar-shaped” nuclei. The cellular atypia was inconspicu- ous. No necrosis was found. There were one mitosis. Immunostain- ing showed positivity for smooth muscle actin and Caldesmone. The Ki67 index was estimated at 4%. The diagnosis was consistent with an intraosseous leiomyoma. A surgical treatment was per- formed with a wide margin’s excision. Conclusion: IL are extremely rare tumours. To the best of our knowledge this is the first reported case occurring in the frontal bone. IL are more common in younger patients. The diagnosis of this tumour is challenging due to its extraordinarily rare incidence and the absence of pathognomonic radiological signs. It is mainly based on histopathologic examination and immunochemistry. Fur- ther studies are needed to study the behaviour of these tumours and their reccurence rates. E-PS-17-007 Myxopapillary ependymoma: a case report and literature review A. Sifre Ruiz*, V. Caamaño, E.N. Camacho, A.P. Martínez Aracil, È. Iglesias, N. Santiago, M.M. Buda, A.I. Ruiz De Angulo Otxaran *Department of Pathology, Hospital Universitario Araba, Spain Background & objectives: Ependymomas are rare tumours origi- nating from neuroepithelial cells. While these tumours mainly occur within the central nervous system (CNS), there are occasional reports in children and young adults with primary tumour occurrence outside of the CNS. Methods: A 63-year-old man presented with a palpable soft tissue mass of 12mm of the sacrococcygeal region of several months of evolution. Magnetic resonance imaging revealed a 12mm mass. He underwent a surgery with histology revealing a myxopapillary tumour. Results: Histology study showed a myxopapillary tumour. The tumour is composed of some papillary structures formed by vessels encircled by basophilic myxoid and collars of cuboidal tumour cells which demonstrate strong GFAP positivity and CKAe1-Ae3. The patient underwent surgery and postoperative magnetic resonance imaging (MRI) of pelvis taken four days after the surgery demon- strating no evidence of residual tumour, recurrence or metastatic disease to the pelvis. Conclusion: Reviewing the literature, we found that the mean patient age at the time of tumour symptomatic occurrence is 47 and the entire medullary conus was involved in 57,1% of the patients. Younger age, preoperative functional capacity, lesser initial neuro- logical deficit, tumour location, size and the extent of resection as well as adjuvant radiotherapy were identified as significant factors influencing better outcome. E-PS-17-008 Aggressiveness of astrocytoma IDH-mutant M. Deacu, A.A. Docu, S. Popescu, S.T. Topliceanu, M. Aschie, M. Bosoteanu, G.C. Cozaru, R.I. Voda, C.I. Orasanu* *Clinical Service of Pathology, ”Sf. Apostol Andrei” Emergency County Hospital, Constanta, Romania; CEDMOG, ”Ovidius” University of Constanta, Romania Background & objectives: Astrocytoma IDH-mutant is a distinct neoplastic entity with different aggressive behaviors depending on the histopathological grade. This pathology remains a challenge for the pathologist, neurosurgeon and oncologist. We describe the character- istics and an analysis of their aggression through ancillary studies. Methods: We conducted a ten years retrospective descriptive study of patients diagnosed in our institution with grade 2, 3 or 4 astrocytomas. Immunohistochemical and cytogenetic tests were performed to stratify the cases according to the IDH gene. The data were entered into SPSS Statistics where they were analysed according to demographic and diagnostic parameters, assessing tumour aggressiveness. Results: We identified 59 cases, most of them were found in the fifth decade of life (30.51%), more common in males (52.54%). The most common histopathological grade was grade 4 (81.36%). Imaging examinations had an accuracy of 92%. The lesion had a diameter of more than 25 mm (88.14%). The average tumour volume was 80.48 mm3, producing displacements of the midline by an average of 8.69 mm. We noticed a higher average survival rate in females (6.5 months) compared to males. The main prognostic factors identified were: Ki-67 index (p<0.001), histopathological grade (p<0.001), age at diagnosis (p=0.040), presence of tumoral residue (p=0.037) and intensity of the IDH1 R132H immunoreaction (p=0.002). Conclusion: We noticed that astrocytomas can appear at any age, not having a specific topography and despite the regional effects, the symptoms do not reveal the degree of aggression. Our study indicated the main negative prognostic factors that are associated with low life expectancy. Thus, the results of our study bring new, up-to-date data to the literature on the characteristics S315