ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 fluid(CSF) with non-enhanced wall. The mass was removed surgically. Histological examination showed a very thin cystic wall with a columnar ciliated coating with numeral mucin-producing cells. The epithelial cells had monomorphic nuclei without atypia. Reactive gliosis was noted in the adjacent glial parenchyma. These findings were consistent with a spinal neurenteric cyst. Conclusion: The neurenteric cyst is a rare congenital anomaly of the medullary canal. There are no specific clinical signs. The size of the cyst and the associated malformations affect the onset of symptoms. The diagnosis is suggested by MRI and confirmed by an anatomo- pathological study of the cyst wall. Surgery is intended to be as radical as possible to avoid relapse. E-PS-20-011 Oral carcinoma cuniculatum in childhood: a rare entity A. Chaachou*, R.A. de Carvalho-Ovalles, C.E. Haro-Haro, M. Alberola-Ferranti, M. Garrido-Pontnou, A. Navarro-Jiménez, J. Camacho *Hospital Universitari Vall d Hebron, Spain Background & objectives: Carcinoma cuniculatum is a rare variant of squamous cell carcinoma (SCC). Only 66 cases affecting oral cavity have been reported to date, three in childhood. We present a case of an 11-year-old girl with oral carcinoma cuniculatum (OCC). Methods: We reviewed the case of a healthy 11-year-old girl pre- senting an indurated excrescent lesion on the right hemi-tongue with a diagnosis of OCC. Results: The biopsy showed a proliferation of well-differentiated squamous cells forming crypts with keratin microabscesses inside, reminiscent of rabbit burrows. A diagnosis of SCC suggestive of OCC was established. A subtotal glossectomy with bilateral cervi- cal lymph node removal was performed. A large tumour size OCC (5 cm) was found with an invasion depth of 24 mm (pT4a), without lymph node involvement (N0) or metastases (M0). The main causes of SCC in children are congenital syndromes (Li- Fraumeni and Fanconi anaemia), immunodeficiency, Epstein-Barr Virus infection and dyskeratosis congenita. However, our patient did not have any of these conditions. Conclusion: OCC is a rare entity that, although it can occur at any age, typically affects people in their seventh or eighth decade. The aetiology and risk factors associated with OCC remain unknown. OCC is locally aggressive but non-metastasizing, with an excellent prognosis after complete resection. The differential diagnosis should be made with benign entities such as osteomyelitis, abscesses, odontogenic or epidermal inclusion cysts, depending on their location. Knowing about this entity is essential to avoid delays and/or erroneous diagnosis. E-PS-20-012 Exencephaly in 23-week-old foetus with placental anomaly N. Unal, A. Yavuz*, C.Y. Sanhal, H.S. Toru *Akdeniz University Department of Pathology, Turkey Background & objectives: Neural tube defects are the most frequent form of congenital central nervous system abnormalities that can lead to several malformations of the nervous system. Incidence varies widely between populations from 1 to 10 per 10,000 births. Methods: There is still much to learn regarding the underlying mechanisms of neural tube defects and understanding them could help prevent countless cases. In our case report, we discussed a primigravid woman, whose unborn child was lost due to a neural tube defect. Results: A 20-year-old primigravid woman appealed to our emer- gency room after her clinical examination in an external clinic showed there was no foetal heartbeat. She was 23 weeks pregnant and she said that her water broke a month ago. In the examination, foetus was observed as male. The face of the foetus had some abnormal features that may be linked to a diagnosis: flat nasal bridge, low-set ears, micrognathia and long philtrum. Anal opening was observed to be normal. Pathological findings were developmental retardation, encephalocele, exencephaly, hypertelorism, empty sella, and grade III maceration. Two vascular structures (one artery and one vein) were observed in the umbilical cord. Retroplacental hematoma was observed. Conclusion: The woman in our case is young and primigravid. There is a great deal of genetic contribution in the development of neural tube defects. The recurrence of neural tube defects after an index case being diagnosed is about %2-5. Routine genetic testing and counselling at least to the women who experience such termi- nation in their first pregnancies would be useful for both under- standing the genetic basis of neural tube defects and preventing later abortions with couples who have genetic predispositions. E-PS-20-013 Evaluation of the recurrency risk of basal plate myometrial fibres F. Rosa*, S. Guimarães *Instituto Português de Oncologia de Lisboa Francisco Gentil, Portugal Background & objectives: In May 2020 an expert panel proposed guidelines for classification and reporting of placenta accreta spectrum (PAS) disorders. The basal plate myometrial fibres (BPMF) category is defined for delivered placentas and portend a risk for PAS in a subsequence pregnancy. Methods: Between 2007 and 2022, 8 cases of placentas with BPMF that had a subsequent pregnancy were found. The slides were reviewed and reclassified. Data regarding maternal age, par- ity, prior caesarean delivery, and gestational age was collected. The subsequent delivery history was analysed regarding complications that may relate to BPMF recurrence and, when available, the slides were review and reclassified. Results: At BPMF first occurrence the mean maternal age was 31 years (range: 22-38). Three were primiparous and four had a prior caesarean. Six were term placentas and two were preterm (28 and 33 gestational weeks). BPMF were equally distributed as stage 1 and 2 with a mean foci number of 3 (range: 1-7) and a mean linear extension of 4,4mm (range: 0,4-6,9mm). The subsequent pregnancy outcomes showed 5 placentas with patho- logical evaluation, of which 2 had BPMF recurrences, corresponding to index cases stage 2. They were stage 1 and 2, with 1 and 5 foci, the largest with 2,3mm and 7,7mm, respectively. The 3 remaining deliver- ies had no complications. Conclusion: In our series the only clinical factor possibly associ- ated with the development of BMPF was a prior caesarean delivery history. The risk of recurrent BPMF in a subsequent pregnancy seems relevant and associated with a prior stage 2 BPMF. More data is needed in order to develop recommendations regarding clinical management of pregnancies with a prior BPMF and the risk of future PAS. S325