ECP 2023 Abstracts

S152 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 For NGS studies we used XCeloSeq Fusion Research kit (GeneFirst Ltd., UK) on sequencing platforms NextSeq 550/550Dx Illumina. Results: Diagnosis was established by transbronchial biopsy from the upper lobe of right lung. Tumour was tubular and solid, cells were polymorphous with irregular nuclei, conspicuous nucleoli and amphophilic cytoplasm. Tumorous cells were IHC positive for ROS-1, NGS analysis disclosed translocation t(5;6)(q33;q22), CD74-ROS1. On autopsy we observed pronounced lymphatic drawing of lungs and pericardium, metastases were present in thyroid and lymph nodes (cervical, thoracic, abdominal). Microscopically were present similar tumorous elements with larger polymorphy, but this time were ROS1 negative in IHC and NGS studies. In lungs was prominent fibrosis devoid of tumorous cells at the primary site, in other lobes there were dilated lymphatics with adenocarcinoma and massive alveolar oedema. Conclusion: ROS1 is tyrosine kinase receptor, CD74 is receptor facili- tating permeability of lymphatics. CD74-ROS1 is rare fusion gene, which serves as oncogene and simultaneously enables early lymphang- iopathy. Our patient was initially diagnosed in advanced IVB stage with multiple extrathoracic metastases. Treatment with ALK inhibitors eradicated primary tumour and metastases at several locations (brain, adrenals, vertebrae) and stabilized the disease. Unfortunately, the ade- nocarcinoma became negative for CD74-ROS1, resulting in massive carcinomatous lymphangiopathy. Consequential massive pulmonary oedema caused respiratory failure. Supported by MH CZ – DRO (Thomayer University Hospital – TUH, 00064190). E-PS-01-023 Thanatophoric dysplasia: case report and literature review A. Van Der Biezen*, M.N. Villca Huayta, C. Vieru, M. García Martos *Hospital General Universitario Gregorio Marañón, Spain Background & objectives: Thanatophoric dysplasia (TD) is a rare and lethal form of osteochondrodysplasia. It is caused by mutations of the gene encoding fibroblast growth factor receptor 3 (FGFR3). We present one case of TD with genetic confirmation. Methods: A 24-week gestational-age female foetus with skeletal mal- formations was delivered to a 37-year-old G2P1 mother. The ultrasound scan at 21 weeks for morphologic evaluation showed micromelia with angulation of the extremities, prompting the diagnosis of skeletal dys- plasia. The mother has no personal history of interest or family his- tory of skeletal dysplasia. It concluded with feticide and request for an autopsy. Results: CT scan showed micromelia, craniofacial disproportion, narrow thorax with hypoplastic lungs, and vertebral body ossification defect. Postmortem examination showed a female foetus, weighing 650 g. The external examination findings revealed macrocephaly, a depressed nasal bridge, low-set ears, a narrow chest with the pres- ence of short ribs, and the upper and lower limbs were symmetrically short. Histologically slides from the ribs and femur demonstrated atypical endochondral ossification. The epiphyseal growth plate was severely retarded and disorganized, with hypertrophic chondrocytes and absence of column formation. The molecular analysis detected mutation of FGFR3, c.742C>T, p.Arg248Cys. Conclusion: Thanatophoric dysplasia is the most common lethal skel- etal dysplasia with an estimated incidence of 1 in 20.000 to 40.000 births. Although TD is autosomal dominant, the majority occurs spo- radically and the recurrence risk is low. We present one case with radiologic, morphologic, histologic, and molecular features, herein described, which were compatible with TD Type 1. Even though TD is a rare condition, skillful antenatal sonographic can be used to obtain an accurate prenatal diagnosis. E-PS-01-024 Congenital intracranial immature teratoma: presentation of a case and a systematic review of the literature A. Van Der Biezen*, M.N. Villca Huayta, M.L. Abascal Camacho, F.J. Díaz Crespo, F. Arías *Hospital General Universitario Gregorio Marañón, Spain Background & objectives: Congenital intracranial tumours are rare and only account for 0.5-1.5% of all paediatric brain tumours. Teratoma is the most frequently encountered intracranial tumour at birth. We present a case of congenital intracranial immature teratoma to describe clinicopathological correlation. Methods: Obstetric ultrasonography in a 31 week-old-foetus revealed a large cranial mass with hydrocephalus. An urgent MRI showed a solid, heterogeneous, lobulated mass with extensive cystic and calcified areas, in the left cerebral hemisphere measuring 11 cm, surrounded by markedly dilated lateral ventricles. It concluded with a feticide at 33 weeks and a request for an autopsy. Results: A 33-week gestational-age foetus was delivered to a 32-year-old G3P2 mother. Postmortem examination showed a male foetus, weighing 3100 g. The external examination findings revealed macrocephaly with wide fontanelle and retrognathia. The brain weighed 251 g and exami- nation showed a replacement of the left side of the brain by a solid and cystic haemorrhagic mass, with no remarkable findings in the remaining organs. Histologically, the mass was composed predominantly of imma- ture neuroepithelial tissue forming rosette-like structures and tubules. It also contained cystic spaces lined by columnar epithelium, immature mesenchyma with rhabdomyoblastic differentiation, cartilage and mus- cle. Morphologic findings were consistent with an immature teratoma. Conclusion: We present a congenital intracranial teratoma to further expand our knowledge of this rare pathology which bears a poor progno- sis and low survival rate. Since there are no significantly associated risk factors known to date, we emphasize the importance of an early diagnosis and a multidisciplinary approach, as an early termination of pregnancy may avoid obstetric and psychological complications for the mother. E-PS-02 | E-Posters Breast Pathology E-PS-02-003 Adenoid cystic carcinoma of the breast: can we predict its aggressiveness? I. Amat Villegas*, E. Carracedo Vega, Y. Ruiz de Azua, I. Fernández De Los Reyes, R. Beloqui, A. Pasco Pena, A. Córdoba *Hospital Universitario de Navarra, Spain Background & objectives: Breast adenoid cystic carcinoma (BACC) is an uncommon neoplasm, typically triple negative, usually with a favourable prognosis although sometimes is aggressive. We apply three different grading schemes and immunohistochemistry antibod- ies through a series of 14 cases. Methods: We analysed the clinicopathological and immunohistochemi- cal features of all BACC and grade them according to the different sys- tems proposed in order to distinguish the aggressiveness of each tumour. Results: Our BACC had an average tumour size of 23.4mm. All patients were women (78.5% over 60 yo.) and underwent surgical resection. Nine women had axillary lymph node staging, one presented micrometastases. One woman developed local recurrence and two died from disease. Nine women underwent radiotherapy and six chemo- therapy and four no adjuvant treatment. None cases have a pure growth pattern, all weremixed, and solidwas themost common. Tumour borders were pushing in six cases and infiltrative in eight. All cases were classify according to the Nottingham, Spiro and Perzing grading system. Immunohistochemical profile was 13 cases triple nega- tive, 71.5% positive for MYB and 85.7% for CD117.