Spitz melanocytic tumours – a review

Spitz tumours comprise a spectrum of melanocytic proliferations that share a set of distinct cytological features and molecular pathways. They include benign naevi, intermediate or indeterminate tumours and rare melanomas. Spitz tumours are notorious for the difficulty of distinguishing benign neoplasms with atypical features from melanomas and the related diagnostic uncertainty. Advances in the knowledge of the molecular pathways and genomic aberrations associated with these neoplasms have permitted opportunities for a reduction in the number of uncertain diagnoses and a more objective distinction between Spitz tumours from Spitz-like neoplasms. The presence of a Spitz molecular pathway, such as Harvey rat sarcoma viral oncogene homologue (HRAS) aberrations or kinase fusions, distinguishes a bona fide Spitz neoplasm from Spitz-like naevi or melanomas with conventional driver mutations. Spitz neoplasms with benign histopathological features and, if such testing is performed, benign cytogenetic and molecular findings, are termed Spitz naevi. Spitz neoplasms with frankly malignant histopathological findings or ambiguous microscopic findings associated with genetic or genomic aberrations most in keeping with melanoma are designated as Spitz melanoma. Tumours with microscopic features and genetic/genomic aberrations in between naevi and melanomas are classified as Spitz melanocytoma.     

Molecular testing for melanocytic tumors: a practical update

The work-up of melanocytic tumors has undergone significant changes in the last years following the exponential growth of molecular assays. For the practicing pathologist it is often difficult to sort through the myriad of different tests available currently for clinical use. The molecular tests used in melanocytic pathology can be broadly divided into 4 categories: (i) Tests useful in the differential diagnosis of nevus versus melanoma (primarily used as an aid in the diagnosis of histologically ambiguous melanocytic tumors), (ii) Tests that predict prognosis in melanoma, (iii) Tests useful in the classification of melanocytic tumors and (iv) Tests that predict response to systemic therapy in melanoma. This review will present an updated overview of major ancillary tests used in clinical practice.     

TRIM59 通过结合 BCLAF1 调控人皮肤黑色素瘤 SK-MEL-2 细胞的恶 性生物学行为

目的：探究三结构域蛋白59（TRIM59）调控人皮肤黑色素瘤细胞SK-MEL-2增殖、细胞周期、凋亡及迁移侵袭的作用机制，及其与Bcl2相关转录因子1（BCLAF1)之间的关系。方法：qPCR和WB法检测人表皮黑色素细胞HEMn-LP、人皮肤黑色素瘤细胞SK-MEL-2、UACC903、A375及36例邢台市人民医院2019年2月至2021年7月收集的皮肤黑色素瘤组织中TRIM59的mRNA和蛋白表达，使用脂质体将si-con、si-TRIM59转染至SK-MEL-2细胞中，WB法检测干扰TRIM59表达对细胞中周期蛋白D1（CCND1）、细胞周期素依赖性激酶2（CDK2）、肿瘤抑制蛋白基因（TP53）和 BCLAF1 蛋白表达的影响，CCK-8法、流式细胞术、划痕愈合实验、Transwell实验检测对细胞的活性、凋亡、迁移和侵袭的影响，免疫共沉淀（Co-IP）实验检测对细胞中TRIM59蛋白与BCLAF1结合能力的影响。结果：与HEMn-LP细胞相比，SK-MEL-2、UACC903、A375细胞中TRIM59 mRNA和TRIM59、BCLAF1蛋白均呈高表达（均P<0.05），SK-MEL-2细胞中TRIM59表达水平最高。相较于si-con组和Normal组，沉默TRIM59后，SK-MEL-2细胞的活性显著降低，细胞周期阻滞于G2期，CCND1、CDK2的蛋白表达显著降低，TP53蛋白和细胞凋亡率均显著升高，划痕抑制率明显升高，迁移侵袭细胞数明显降低（均P<0.05）。免疫共沉淀实验结果显示，TRIM59与BCLAF1之间存在蛋白结合关系。TRIM59与 BCLAF1 在肿瘤组织中的表达呈显著的正相关（r=0.878，P<0.001）。结论：干扰TRIM59表达能够抑制人皮肤黑色素瘤SK-MEL-2细胞的增殖、迁移和侵袭而促进凋亡，抑制SK-MEL-2细胞的恶性生物学行为，其机制可能与TRIM59结合BCLAF1有关。     

Reflectance confocal microscopy may enhance the accuracy of histopathologic diagnosis: A case series

Although histopathology is the time‐honored gold standard diagnostic measure in dermatology, several factors may detract from an accurate microscopic diagnosis. Limiting factors include: human error, suboptimal biopsy‐site selection or biopsy technique, and inherent restrictions of vertical tissue sectioning that lead to incomplete microscopic evaluation of the lesion. Reflectance confocal microscopy (RCM) is a non‐invasive imaging tool that allows for the cellular‐level examination of the lesion, at a horizontal plane, which may complement the subsequent vertical histopathological tissue examination. Herein, we report a case series whereby prebiopsy RCM examination enhanced the accuracy of histopathological diagnosis or allowed for a critical appraisal of initial histopathological misdiagnosis.     

A challenging breast biopsy

Metastases to the breast are an uncommon occurrence and can mimic primary breast carcinoma clinically and morphologically. We report a case of metastatic melanoma that presented as a breast mass. We review the literature on metastases to the breast from any source and discuss the microscopic features that can help differentiate metastatic melanoma from primary breast cancer.     

Sinonasal tract pathology: an updated review of select entities

The sinonasal tract is host to numerous benign and malignant entities that can pose diagnostic challenges to pathologists as a result of limited exposure in daily practice. This review concentrates on certain key characteristics of select entities with focus on differential diagnosis, novel subtypes and/or molecular distinction. The aim of this review is to summarize current knowledge and shed light on diagnostically challenging and emerging entities in sinonasal tract pathology.     

A diagnostically‐challenging case of melanoma ex blue nevus with comprehensive molecular analysis,including the 23‐gene expression signature (myPath melanoma)

Melanoma ex blue nevus (MEBN) is a rare, aggressive, and potentially lethal neoplasm. Distinguishing MEBN from an atypical cellular blue nevus can be very challenging. We report a diagnostically difficult case of MEBN with lymph node metastases, in which single nucleotide polymorphism array and fluorescence in situ hybridization were used to arrive at the correct diagnosis. It was also analyzed by the recently‐introduced proprietary 23‐gene expression signature test. To the best of our knowledge, this is the second reported case of MEBN analyzed by the 23‐gene expression signature, which provided a false‐negative result. More studies are needed to assess the sensitivity and specificity of this test in various melanocytic proliferations.