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Most-read articles are from the articles published in 2020 during the last three month.

Original Article
Prevalence of high-risk human papillomavirus and its genotype distribution in head and neck squamous cell carcinomas
Yuil Kim, Young-Hoon Joo, Min-Sik Kim, Youn Soo Lee
J Pathol Transl Med. 2020;54(5):411-418.   Published online July 21, 2020
DOI: https://doi.org/10.4132/jptm.2020.06.22
  • 4,896 View
  • 125 Download
  • 8 Citations
AbstractAbstract PDF
Background
High-risk (HR) human papillomavirus (HPV) is found in a subset of head and neck (HN) squamous cell carcinomas (SCCs). For oropharyngeal SCCs, HR HPV positivity is known to be associated with good prognosis, and a separate staging system for HPV-associated carcinomas using p16 immunohistochemistry (IHC) as a surrogate test has been adopted in the 8th American Joint Committee on Cancer staging system. We examined the HR HPV status and the genotype distribution in five HN subsites.
Methods
Formalin-fixed paraffin-embedded tissue sections were used for p16 IHC and DNA extraction. HPV DNA detection and genotyping were done employing either a DNA chip-based or real-time polymerase chain reaction–based method.
Results
During 2011–2019, a total of 466 SCCs were tested for HPV DNA with 34.1% positivity for HR HPV. Among HN subsites, the oropharynx showed the highest HR HPV prevalence (149/205, 75.1%), followed by the sinonasal tract (3/14, 21.4%), larynx (5/43, 11.6%), hypopharynx (1/38, 2.6%), and oral cavity (1/166, 0.6%). The most common HPV genotype was HPV16 (84.3%) followed by HPV35 (6.9%) and HPV33 (4.4%). Compared with HR HPV status, the sensitivity and specificity of p16 IHC were 98.6% and 94.3% for the oropharynx, and 99.2% and 93.8% for the tonsil, respectively.
Conclusions
Using a Korean dataset, we confirmed that HR HPV is most frequently detected in oropharyngeal SCCs. p16 positivity showed a good concordance with HR HPV DNA for oropharyngeal and especially tonsillar carcinomas. The use of p16 IHC may further be extended to predict HR HPV positivity in sinonasal tract SCCs.
Review
2019 Practice guidelines for thyroid core needle biopsy: a report of the Clinical Practice Guidelines Development Committee of the Korean Thyroid Association
Chan Kwon Jung, Jung Hwan Baek, Dong Gyu Na, Young Lyun Oh, Ka Hee Yi, Ho-Cheol Kang
J Pathol Transl Med. 2020;54(1):64-86.   Published online January 15, 2020
DOI: https://doi.org/10.4132/jptm.2019.12.04
  • 15,698 View
  • 682 Download
  • 18 Citations
AbstractAbstract PDF
Ultrasound-guided core needle biopsy (CNB) has been increasingly used for the pre-operative diagnosis of thyroid nodules. Since the Korean Society of the Thyroid Radiology published the ‘Consensus Statement and Recommendations for Thyroid CNB’ in 2017 and the Korean Endocrine Pathology Thyroid CNB Study Group published ‘Pathology Reporting of Thyroid Core Needle Biopsy’ in 2015, advances have occurred rapidly not only in the management guidelines for thyroid nodules but also in the diagnostic terminology and classification schemes. The Clinical Practice Guidelines Development Committee of the Korean Thyroid Association (KTA) reviewed publications on thyroid CNB from 1995 to September 2019 and updated the recommendations and statements for the diagnosis and management of thyroid nodules using CNB. Recommendations for the resolution of clinical controversies regarding the use of CNB were based on expert opinion. These practical guidelines include recommendations and statements regarding indications for CNB, patient preparation, CNB technique, biopsy-related complications, biopsy specimen preparation and processing, and pathology interpretation and reporting of thyroid CNB.
Case Study
Clinically undetected plasmacytoid urothelial carcinoma of the urinary bladder with non-mass-forming metastases in multiple organs: an autopsy case
Yuya Asano, Kosuke Miyai, Shinya Yoshimatsu, Makoto Sasaki, Katsunori Ikewaki, Susumu Matsukuma
J Pathol Transl Med. 2022;56(4):217-224.   Published online May 3, 2022
DOI: https://doi.org/10.4132/jptm.2022.03.15
  • 1,919 View
  • 105 Download
AbstractAbstract PDF
This case report outlines a clinically undetected urinary bladder plasmacytoid urothelial carcinoma (PUC) with multiple metastases detected at autopsy. An 89-year-old man presented with edema in the lower limbs. Pleural fluid cytology revealed discohesive carcinomatous cells, although imaging studies failed to identify the primary site of tumor. The patient died of respiratory failure. Autopsy disclosed a prostate tumor and diffusely thickened urinary bladder and rectum without distinct tumorous lesions. Histologically, the tumor consisted of acinar-type prostate adenocarcinoma with no signs of metastasis. Additionally, small, plasmacytoid tumor cells were observed in the urinary bladder/rectum as isolated or small clustering fashions. These metastasized to the lungs, intestine, generalized lymph nodes in a non-mass-forming manner. Combined with immunohistochemical studies, these tumor cells were diagnosed PUC derived from the urinary bladder. Both clinicians and pathologists should recognize PUC as an aggressive histological variant, which can represent a rapid systemic progression without mass-forming lesions.
Reviews
HER2 status in breast cancer: changes in guidelines and complicating factors for interpretation
Soomin Ahn, Ji Won Woo, Kyoungyul Lee, So Yeon Park
J Pathol Transl Med. 2020;54(1):34-44.   Published online November 6, 2019
DOI: https://doi.org/10.4132/jptm.2019.11.03
  • 12,943 View
  • 790 Download
  • 34 Citations
AbstractAbstract PDF
Human epidermal growth factor receptor 2 (HER2) protein overexpression and/or HER2 gene amplification is found in about 20% of invasive breast cancers. It is a sole predictive marker for treatment benefits from HER2 targeted therapy and thus, HER2 testing is a routine practice for newly diagnosed breast cancer in pathology. Currently, HER2 immunohistochemistry (IHC) is used for a screening test, and in situ hybridization is used as a confirmation test for HER2 IHC equivocal cases. Since the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines on HER2 testing was first released in 2007, it has been updated to provide clear instructions for HER2 testing and accurate determination of HER2 status in breast cancer. During HER2 interpretation, some pitfalls such as intratumoral HER2 heterogeneity and increase in chromosome enumeration probe 17 signals may lead to inaccurate assessment of HER2 status. Moreover, HER2 status can be altered after neoadjuvant chemotherapy or during metastatic progression, due to biologic or methodologic issues. This review addresses recent updates of ASCO/CAP guidelines and factors complicating in the interpretation of HER2 status in breast cancers.
Lymphoproliferative disorder involving body fluid: diagnostic approaches and roles of ancillary studies
Jiwon Koh, Sun Ah Shin, Ji Ae Lee, Yoon Kyung Jeon
J Pathol Transl Med. 2022;56(4):173-186.   Published online July 4, 2022
DOI: https://doi.org/10.4132/jptm.2022.05.16
  • 1,765 View
  • 109 Download
AbstractAbstract PDF
Lymphocyte-rich effusions represent benign reactive process or neoplastic condition. Involvement of lymphoproliferative disease in body cavity is not uncommon, and it often causes diagnostic challenge. In this review, we suggest a practical diagnostic approach toward lymphocyte-rich effusions, share representative cases, and discuss the utility of ancillary tests. Cytomorphologic features favoring neoplastic condition include high cellularity, cellular atypia/pleomorphism, monomorphic cell population, and frequent apoptosis, whereas lack of atypia, polymorphic cell population, and predominance of small T cells usually represent benign reactive process. Involvement of non-hematolymphoid malignant cells in body fluid should be ruled out first, followed by categorization of the samples into either small/medium-sized cell dominant or large-sized cell dominant fluid. Small/medium-sized cell dominant effusions require ancillary tests when either cellular atypia or history/clinical suspicion of lymphoproliferative disease is present. Large-sized cell dominant effusions usually suggest neoplastic condition, however, in the settings of initial presentation or low overall cellularity, ancillary studies are helpful for more clarification. Ancillary tests including immunocytochemistry, in situ hybridization, clonality test, and next-generation sequencing can be performed using cytologic preparations. Throughout the diagnostic process, proper review of clinical history, cytomorphologic examination, and application of adequate ancillary tests are key elements for successful diagnosis.
Original Articles
Clinicopathologic features and survival outcomes of ocular melanoma: a series of 31 cases from a tertiary university hospital
Selin Kestel, Feriha Pınar Uyar Göçün, Betül Öğüt, Özlem Erdem
J Pathol Transl Med. 2022;56(4):187-198.   Published online May 3, 2022
DOI: https://doi.org/10.4132/jptm.2022.03.10
  • 1,874 View
  • 128 Download
AbstractAbstract PDFSupplementary Material
Background
We aimed to determine the effect of clinicopathologic features on overall survival among Caucasian ocular melanoma patients in the Central Anatolia region of Turkey.
Methods
This single-center study included conjunctival (n = 12) and uveal (n = 19) melanoma patients diagnosed between January 2008 and March 2020. Clinicopathologic features and outcomes were reviewed retrospectively. Five cases were tested for BRAF V600 mutations with real-time polymerase chain reaction, and one case was tested with nextgeneration sequencing. Survival was calculated using the Kaplan-Meier method.
Results
Thirty-one patients had a mean initial age of 58.32 years (median, 61 years; range 25 to 78 years). There were 13 male and 18 female patients. The median follow-up time was 43.5 months (range, 6 to 155 months) for conjunctival melanoma and 35 months (range, 8 to 151 months) for uveal melanoma. When this study ended, eight of the 12 conjunctival melanoma patients (66.7%) and nine of the 19 uveal melanoma patients (47.4%) had died. The presence of tumor-infiltrating lymphocytes was related to improved overall survival in conjunctival melanoma (p = .014), whereas the presence of ulceration (p = .030), lymphovascular invasion (p = .051), tumor in the left eye (p = .012), tumor thickness of > 2 mm (p = .012), and mitotic count of >1/mm² (p = .012) reduced the overall survival in conjunctival melanoma. Uveal melanoma tumors with the largest diameter of 9.1–15 mm led to the lowest overall survival among subgroups (p = .035). Involvement of the conjunctiva (p=.005) and lens (p = .003) diminished overall survival in uveal melanoma. BRAF V600 mutation was present in one case of conjunctival melanoma, GNAQ R183Q mutation was present in one case of uveal melanoma. Patients with uveal melanoma presented with an advanced pathological tumor stage compared to those with conjunctival melanoma (p = .019).
Conclusions
This study confirmed the presence of tumor-infiltrating lymphocytes as a favorable factor in conjunctival melanoma and conjunctival and lens involvement as unfavorable prognostic factors in uveal melanoma for overall survival, respectively.
EGFL7 expression profile in IDH-wildtype glioblastomas is associated with poor patient outcome
Bruno Henrique Bressan da Costa, Aline Paixão Becker, Luciano Neder, Paola Gyuliane Gonçalves, Cristiane de Oliveira, Allan Dias Polverini, Carlos Afonso Clara, Gustavo Ramos Teixeira, Rui Manuel Reis, Lucas Tadeu Bidinotto
J Pathol Transl Med. 2022;56(4):205-211.   Published online June 15, 2022
DOI: https://doi.org/10.4132/jptm.2022.04.22
  • 1,620 View
  • 71 Download
AbstractAbstract PDFSupplementary Material
Background
Despite the advances in glioblastoma (GBM) treatment, the average life span of patients is 14 months. Therefore, it is urgent to identity biomarkers of prognosis, treatment response, or development of novel treatment strategies. We previously described the association of high epidermal growth factor-like domain multiple 7 (EGFL7) expression and unfavorable outcome of pilocytic astrocytoma patients. The present study aims to analyze the prognostic potential of EGFL7 in GBM isocitrate dehydrogenase (IDH)-wildtype, using immunohistochemistry and in silico approaches.
Methods
Spearman’s correlation analysis of The Cancer Genome Atlas RNA sequencing data was performed. The genes strongly correlated to EGFL7 expression were submitted to enrichment gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Additionally, EGFL7 expression was associated with patient overall survival. The expression of EGFL7 was analyzed through immunohistochemistry in 74 GBM IDH-wildtype patients’ samples, and was associated with clinicopathological data and overall survival.
Results
In silico analysis found 78 genes strongly correlated to EGFL7 expression. These genes were enriched in 40 biological processes and eight KEGG pathways, including angiogenesis/vasculogenesis, cell adhesion, and phosphoinositide 3-kinase–Akt, Notch, and Rap1 signaling pathways. The immunostaining showed high EGFL7 expression in 39 cases (52.7%). High immunolabelling was significantly associated with low Karnofsky Performance Status and poor overall survival. Cox analysis showed that GBMs IDH-wildtype with high EGFL7 expression presented a higher risk of death compared to low expression (hazard ratio, 1.645; 95% confidence interval, 1.021 to 2.650; p = .041).
Conclusions
This study gives insights regarding the genes that are correlated with EGFL7, as well as biological processes and signaling pathways, which should be further investigated in order to elucidate their role in glioblastoma biology.
Review
Standardization of the pathologic diagnosis of appendiceal mucinous neoplasms
Dong-Wook Kang, Baek-hui Kim, Joon Mee Kim, Jihun Kim, Hee Jin Chang, Mee Soo Chang, Jin-Hee Sohn, Mee-Yon Cho, So-Young Jin, Hee Kyung Chang, Hye Seung Han, Jung Yeon Kim, Hee Sung Kim, Do Youn Park, Ha Young Park, So Jeong Lee, Wonae Lee, Hye Seung Lee, Yoo Na Kang, Younghee Choi
J Pathol Transl Med. 2021;55(4):247-264.   Published online July 8, 2021
DOI: https://doi.org/10.4132/jptm.2021.05.28
  • 5,106 View
  • 431 Download
  • 2 Citations
AbstractAbstract PDFSupplementary Material
Although the understanding of appendiceal mucinous neoplasms (AMNs) and their relationship with disseminated peritoneal mucinous disease have advanced, the diagnosis, classification, and treatment of AMNs are still confusing for pathologists and clinicians. The Gastrointestinal Pathology Study Group of the Korean Society of Pathologists (GPSG-KSP) proposed a multicenter study and held a workshop for the “Standardization of the Pathologic Diagnosis of the Appendiceal Mucinous Neoplasm” to overcome the controversy and potential conflicts. The present article is focused on the diagnostic criteria, terminologies, tumor grading, pathologic staging, biologic behavior, treatment, and prognosis of AMNs and disseminated peritoneal mucinous disease. In addition, GPSG-KSP proposes a checklist of standard data elements of appendiceal epithelial neoplasms to standardize pathologic diagnosis. We hope the present article will provide pathologists with updated knowledge on how to handle and diagnose AMNs and disseminated peritoneal mucinous disease.
Newsletter
What’s new in breast pathology 2022: WHO 5th edition and biomarker updates
Kristen Muller, Julie M. Jorns, Gary Tozbikian
J Pathol Transl Med. 2022;56(3):170-171.   Published online May 15, 2022
DOI: https://doi.org/10.4132/jptm.2022.04.25
  • 2,851 View
  • 201 Download
AbstractAbstract PDF
The 5th edition WHO Classification of Breast Tumours (2019) has introduced changes to our practices. Highlights are presented below, with a focus on modifications to morphological subtype categorization. In addition, we summarize important updates to ER and PR testing made in the 2020 ASCO/CAP guidelines, and briefly discuss PD-L1 and Ki-67 testing in breast cancer.
Original Article
Correlation between myoferlin expression and lymph node metastasis in papillary thyroid carcinoma
Ji Min Na, Dong Chul Kim, Dae Hyun Song, Hyo Jung An, Hyun Min Koh, Jeong-Hee Lee, Jong Sil Lee, Jung Wook Yang, Min Hye Kim
J Pathol Transl Med. 2022;56(4):199-204.   Published online May 11, 2022
DOI: https://doi.org/10.4132/jptm.2022.03.19
  • 1,491 View
  • 113 Download
AbstractAbstract PDF
Background
Myoferlin is a multifunctional protein expressed in various normal and cancer cells, with novel oncogenic roles being newly discovered. Recently, correlations have been found between myoferlin expression and unfavorable prognosis in various carcinomas. This study investigated the prognostic role of myoferlin expression in papillary thyroid carcinoma (PTC), specifically that associated with nodal metastasis.
Methods
We collected clinicopathological data and PTC tissues from 116 patients who had been admitted to Gyeongsang National University Hospital in 2010. Immunohistochemical analysis was performed on surgical specimen-derived tissue microarray blocks. Myoferlin expression was graded, and the relationship between expression level and pathological features of tumors based on the American Joint Committee on Cancer staging system was evaluated.
Results
Of the 116 patient samples, 100 cases exhibited positive myoferlin expression. Higher grade of myoferlin expression was correlated with lower T category group (p = .010). Presence of lymph node metastasis was determined to be significantly correlated with low-grade myoferlin expression (p = .019), with no significant difference between pN1a and pN1b tumors.
Conclusions
Our study revealed an adverse correlation between myoferlin expression and pathological features of PTC, evidence of the potential prognostic role of myoferlin in PTC lymph node metastasis.
Case Study
Hepatic carcinoma expressing inhibin: case report of a proposed novel entity and review of the literature
Antonia Syrnioti, Evangelia Athanasiou, Prodromos Hytiroglou
J Pathol Transl Med. 2022;56(4):225-230.   Published online June 15, 2022
DOI: https://doi.org/10.4132/jptm.2022.04.07
  • 1,373 View
  • 67 Download
AbstractAbstract PDF
Hepatic carcinoma expressing inhibin is a recently described neoplasm with varied architecture, including trabecular, pseudoglandular, follicular/microcystic, organoid, solid and tubular patterns of growth. We report a case of hepatic carcinoma expressing inhibin that occurred in a 47-year-old woman presenting with epigastric and back pain. The tumor was located in the left hepatic lobe and measured 12 cm in diameter. On immunohistochemical stains, the neoplastic cells were positive for inhibin, as well as cytokeratins 7, 8/18 and 19. There was mild focal expression of synaptophysin, and lack of expression of hepatocytic markers. The histogenesis of hepatic carcinoma expressing inhibin is presently uncertain. From a practical point of view, this neoplasm can potentially cause diagnostic pitfalls by simulating other primary or metastatic tumors, such as hepatocellular carcinoma, cholangiocarcinoma, neuroendocrine tumors, and follicular carcinoma of thyroid gland. Performing inhibin immunostain could assist in the differential diagnosis of liver tumors with unusual histologic features.
Review
Standardized Pathology Report for Colorectal Cancer, 2nd Edition
Baek-hui Kim, Joon Mee Kim, Gyeong Hoon Kang, Hee Jin Chang, Dong Wook Kang, Jung Ho Kim, Jeong Mo Bae, An Na Seo, Ho Sung Park, Yun Kyung Kang, Kyung-Hwa Lee, Mee Yon Cho, In-Gu Do, Hye Seung Lee, Hee Kyung Chang, Do Youn Park, Hyo Jeong Kang, Jin Hee Sohn, Mee Soo Chang, Eun Sun Jung, So-Young Jin, Eunsil Yu, Hye Seung Han, Youn Wha Kim
J Pathol Transl Med. 2020;54(1):1-19.   Published online November 13, 2019
DOI: https://doi.org/10.4132/jptm.2019.09.28
  • 13,812 View
  • 913 Download
  • 15 Citations
AbstractAbstract PDFSupplementary Material
The first edition of the ‘Standardized Pathology Report for Colorectal Cancer,’ which was developed by the Gastrointestinal Pathology Study Group (GIP) of the Korean Society of Pathologists, was published 13 years ago. Meanwhile, there have been many changes in the pathologic diagnosis of colorectal cancer (CRC), pathologic findings included in the pathology report, and immunohistochemical and molecular pathology required for the diagnosis and treatment of colorectal cancer. In order to reflect these changes, we (GIP) decided to make the second edition of the report. The purpose of this standardized pathology report is to provide a practical protocol for Korean pathologists, which could help diagnose and treat CRC patients. This report consists of “standard data elements” and “conditional data elements.” Basic pathologic findings and parts necessary for prognostication of CRC patients are classified as “standard data elements,” while other prognostic factors and factors related to adjuvant therapy are classified as “conditional data elements” so that each institution could select the contents according to the characteristics of the institution. The Korean version is also provided separately so that Korean pathologists can easily understand and use this report. We hope that this report will be helpful in the daily practice of CRC diagnosis.
Original Article
Founder BRCA1 mutations in Nepalese population
Anurag Mehta, Himanshi Diwan, Garima Gupta, Shrinidhi Nathany, Shalini Agnihotri, Surender Dhanda
J Pathol Transl Med. 2022;56(4):212-216.   Published online June 15, 2022
DOI: https://doi.org/10.4132/jptm.2022.05.02
  • 1,413 View
  • 67 Download
AbstractAbstract PDF
Background
Founder mutation is a heritable genetic alteration observed with high frequency in a geographically and culturally isolated population where one or more ancestors becomes the forebearer of the altered gene. The current study reports two founder mutations in the BRCA1 gene in the Nepalese people.
Methods
Germline BRCA testing in all surface epithelial ovarian cancers and the selected case of breast, prostate, and pancreatic cancers has been the standard practice from 2016 to 2021. One thousand one hundred thirtythree probands were screened for germline BRCA variants by next generation sequencing. The variants were classified as per the American Society of Medical Genetics and Genomics recommendations. Pathogenic (class V) and likely pathogenic (class IV) were considered clinically relevant and utilized for cascade screening.
Results
Nepalese population made up a subcohort of 5.12% (58/1,133) of probands tested for germline BRCA1/2 variants. Twenty-seven of these 58 tested harbored pathogenic genetic alterations in BRCA1/2 genes, with 23 being BRCA1 mutant. Sixteen of 23 BRCA1 mutant cases shared one common pathogenic mutation c.2214_2215insT (p.Lys739Ter) (NM_007294.4). Additionally, a second highly recurrent mutation in BRCA1 gene c.5068A>T (p.Lys1690Ter) (NM_007294.4) was noted in six patients from this population.
Conclusions
The overwhelming abundance of the above two variants in a geographically confined population confers these two genetic alterations a status of founder mutations amongst the people of Nepal. A more extensive population-based study to reaffirm these findings will help establish a dual site-specific germline testing similar to the “Multisite-3-assay” in Ashkenazi Jews as the primary screening tool, especially in a resource-constrained environment.
Case Study
Primary pulmonary epithelioid inflammatory myofibroblastic sarcoma: a rare entity and a literature review
Priyanka Singh, Aruna Nambirajan, Manish Kumar Gaur, Rahul Raj, Sunil Kumar, Prabhat Singh Malik, Deepali Jain
J Pathol Transl Med. 2022;56(4):231-237.   Published online July 7, 2022
DOI: https://doi.org/10.4132/jptm.2022.05.08
  • 1,099 View
  • 44 Download
AbstractAbstract PDF
Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an aggressive subtype of inflammatory myofibroblastic tumor (IMT) harboring anaplastic lymphoma kinase (ALK) gene fusions and is associated with high risk of local recurrence and poor prognosis. Herein, we present a young, non-smoking male who presented with complaints of cough and dyspnoea and was found to harbor a large right lower lobe lung mass. Biopsy showed a high-grade epithelioid to rhabdoid tumor with ALK and desmin protein expression. The patient initially received 5 cycles of crizotinib and remained stable for 1 year; however, he then developed multiple bony metastases, for which complete surgical resection was performed. Histopathology confirmed the diagnosis of EIMS, with ALK gene rearrangement demonstrated by fluorescence in situ hybridization. Postoperatively, the patient is asymptomatic with stable metastatic disease on crizotinib and has been started on palliative radiotherapy. EIMS is a very rare subtype of IMT that needs to be included in the differential diagnosis of ALKexpressing lung malignancies in young adults.
Review
Evolving pathologic concepts of serrated lesions of the colorectum
Jung Ho Kim, Gyeong Hoon Kang
J Pathol Transl Med. 2020;54(4):276-289.   Published online June 26, 2020
DOI: https://doi.org/10.4132/jptm.2020.04.15
  • 7,221 View
  • 520 Download
  • 10 Citations
AbstractAbstract PDFSupplementary Material
Here, we provide an up-to-date review of the histopathology and molecular pathology of serrated colorectal lesions. First, we introduce the updated contents of the 2019 World Health Organization classification for serrated lesions. The sessile serrated lesion (SSL) is a new diagnostic terminology that replaces sessile serrated adenoma and sessile serrated polyp. The diagnostic criteria for SSL were revised to require only one unequivocal distorted serrated crypt, which is sufficient for diagnosis. Unclassified serrated adenomas have been included as a new category of serrated lesions. Second, we review ongoing issues concerning the morphology of serrated lesions. Minor morphologic variants with distinct molecular features were recently defined, including serrated tubulovillous adenoma, mucin-rich variant of traditional serrated adenoma (TSA), and superficially serrated adenoma. In addition to intestinal dysplasia and serrated dysplasia, minimal deviation dysplasia and not otherwise specified dysplasia were newly suggested as dysplasia subtypes of SSLs. Third, we summarize the molecular features of serrated lesions. The critical determinant of CpG island methylation development in SSLs is patient age. Interestingly, there may be ethnic differences in BRAF/KRAS mutation frequencies in SSLs. The molecular pathogenesis of TSAs is divided into KRAS and BRAF mutation pathways. SSLs with MLH1 methylation can progress into favorable prognostic microsatellite instability-positive (MSI+)/CpG island methylator phenotype-positive (CIMP+) carcinomas, whereas MLH1-unmethylated SSLs and BRAF-mutated TSAs can be precursors of poor-prognostic MSI−/CIMP+ carcinomas. Finally, based on our recent data, we propose an algorithm for stratifying risk subgroups of non-dysplastic SSLs.

JPTM : Journal of Pathology and Translational Medicine