The BRAFV600E Mutation Is Not a Risk Factor for More Aggressive Tumor Behavior in Radiogenic and Sporadic Papillary Thyroid Carcinoma at a Young Age

Histopathological changes in the fusion oncogene-driven papillary thyroid carcinomas (PTCs) from children and adolescents exposed to Chernobyl fallout have been extensively studied. However, characteristics of the radiogenic BRAFV600E-positive PTCs, whose proportion is growing with time, are not well described yet. We analyzed the relationship between the BRAFV600E status (determined immunohistochemically with the VE1 antibody) and the clinicopathological features of 247 radiogenic and 138 sporadic PTCs from young Ukrainian patients aged ≤28 years. The frequency of BRAFV600E was increasing with patient age, consistently remaining lower in radiogenic PTCs. In both etiopathogenic groups, the BRAFV600E-positive PTCs more frequently had a dominant papillary growth pattern, smaller tumor size, higher Ki67 labeling index, and a frequency of the major indicators of tumor invasiveness that is lower than or equal to that of the BRAFV600E-negative tumors. Comparison of the BRAFV600E-positive PTCs across the groups found a virtual absence of differences. In contrast, the BRAFV600E-negative radiogenic PTCs displayed less frequent dominant papillary and more frequent solid growth patterns, lower Ki67 labeling index, and higher invasiveness than the BRAFV600E-negative sporadic tumors. Thus, BRAFV600E is not associated with a more aggressive course of PTC in young patients regardless of etiology. The major clinicopathological differences between the radiogenic and sporadic PTCs are observed among the BRAFV600E-negative tumors.

Challenging of frozen diagnoses of small sclerosing pneumocytoma

AimsAn increasing number of small pulmonary nodules are being screened by CT, and an intraoperative diagnosis is necessary for preventing excessive treatment. However, there is limited literature on the frozen diagnosis of small sclerosing pneumocytomas (SPs). In particular, tumours smaller than 1 cm are challenging for pathologists performing intraoperative frozen diagnosis.MethodsIn total, 230 cases of SP were surgically resected between January 2015 and March 2019 at Shanghai Chest Hospital, and of them, 76 cases were smaller than 1 cm. The histology and clinical information of these 76 cases (33.0%, 76/230) were reviewed retrospectively, 54 cases of which were diagnosed intraoperatively, and the pitfalls were summarised. All diagnoses were confirmed on permanent sections and immunohistochemical sections.ResultsHistologically, 78.9% (60/76) of the small SP was dominated by one growth pattern, and solid and papillary growth pattern were the most commonly misdiagnosed circumstances. The rate of intraoperative misdiagnosis of these SP smaller than 1 cm was 11.1% (6/54).ConclusionsThe main reason for misdiagnosis was failure to recognise the dual cell populations and the cellular atypia. Diagnostic clues include the gross morphology, the presence of dual-cell populations and a hypercellular papillary core, foam cell accumulation in glandular spaces and haemorrhage and haemosiderin on the periphery. In spite of awareness of pitfalls some cases may still be essentially impossible to diagnose on frozen section.

PATH-16. HISTOPATHOLOGICAL EPENDYMOMA VARIANTS ARE ASSOCIATED WITH DISTINCT CLINICAL PARAMETERS AND DNA METHYLATION PATTERNS

According to the current WHO classification, ependymal tumors are classified as subependymomas, myxopapillary ependymomas, classic ependymomas, anaplastic ependymomas and RELA-fusion positive ependymoma (RELA-EPN). Among classic ependymomas, the WHO defines rare histological variants, i.e. the clear-cell, papillary, and tanycytic ependymoma. In parallel to this WHO classification scheme, DNA methylation patterns can distinguish nine distinct molecular ependymoma subgroups, some of which tightly overlap with certain histopathological subgroups, e.g. subependyomas or myxopapillary ependymomas. Since very little is known about the molecular background of histological classic ependymoma variants, we analyzed histomorphology, clinical parameters and global DNA methylation patterns of diagnosed tanycytic ependymomas (n=12), clear-cell ependymomas (n=14) and papillary ependymomas (n=19). Surprisingly, up to 42% of these variants did not match to ependymomas using a previously published DNA methylation-based classifier for brain tumors. Among the tumors with a match to one of the nine known ependymoma methylation classes, tanycytic ependymomas were predominantly located in the spine, but showed diverse molecular methylation patterns. Most clear-cell ependymomas showed a common histomorphology, were found supratentorially and fell into the methylation class of RELA-EPN. Papillary ependymomas showed a “papillary”, “trabecular” or “pseudo-papillary” growth pattern. Interestingly, a true papillary growth pattern was strongly associated with the molecular class B of posterior fossa ependymoma (PFB), but tumors displayed DNA methylation sites that were significantly different when compared to PFB ependymomas without papillary growth. Our results show that the diagnosis of classic histological ependymoma variants can be challenging. While clear-cell and papillary ependymomas harbor common molecular features, tanycytic ependymoma may not represent a molecularly distinct subgroup.

Epithelial papillary angioepithelioma pada rongga sinus maksila wanita dewasa muda

Latar belakang: Epithelial Papillary Angioepithelioma (EPA) yang dikenal juga sebagai tumor Dabska adalah suatu tumor vaskular yang jarang terjadi pada rongga hidung dan sinus paranasalis. Tindakan bedah, radioterapi dan kemoterapi serta kombinasi ketiganya adalah pengobatan utama untuk tumor ganas sinonasal. Tujuan: Memberikan informasi mengenai diagnosis dan penatalaksanaan tumor Dabska. Kasus: Kasus langka ini ditemukan pada wanita usia 16 tahun dengan massa tumor pada rongga hidung dan sinus paranasal yang berekstensi hingga rongga mulut. Pemeriksaan histopatologi didapatkan sel tumor endothelial yang menunjukkan pola pertumbuhan papiler. Pemeriksaan imunohistokimiaCD34 positif. Penatalaksanaan: Radioterapi preoperasi 10 kali untuk mengurangi massa tumor yang progresif kemudian dilakukan maksilektomi infrastruktur dilanjutkan radioterapi postoperasi. Dilakukan juga pemasangan protesa palatum bars postoperasi dan protesa palatomaksilaris 3 bulan pasca operasi. Evaluasi pasca operasi tampak perbaikan, tidak didapatkan infeksi maupun tanda-tanda kekambuhan,dan secara anatomi fungsi kembali seperti semula. Kesimpulan: Diagnosis dan penatalaksanaan yang cepat dan tepat dapat meningkatkan prognosis pada tumor DabskaKata kunci: Tumor Dabska, maksilektomi infrastruktur, radioterapi, tumor sinonasal, protesa ABSTRACTBackground: Epithelial papillary angioepithelioma (EPA), also known as Dabska tumor, is a very rare vascular neoplasm in the sinonasal. Surgery, radiotherapy and chemotherapy, and the combination of those three are the primary treatment for malignant sinonasal tumors. Purpose: To inform about the diagnostic and treatment of Dabska tumor. Case: We present an exceptionally rare case of EPA of the sinonasal in a 16 year old female. A well defined, reddish tumor existed at the sinonasal that extended to oral cavity. Microscopic examination revealed the endothelioid tumor cells showing a papillary growth pattern with positive imunohistchemistry of CD34. Management: Ten consecutive radiotherapies was performed preoperatively and then continued with progressive infrastructure maxillectomy andreconstructions of the maxilla, followed by postoperative radiotherapies. Postoperative management also include the mounting bars palate prosthesis and palatomaxillary prosthesis 3-month after the operation. Postoperative evaluation showed improvement, there was no sign of any infection or recurrence, and the anatomical function returned to normal. Conclusion: Prompt diagnosis and the rightmanagement could improve the prognosis in Dabska tumors.Keywords: Dabska tumor, infrastructure maxillectomy, radiotherapy, sinonasal neoplasm, prosthesis