Differences in mutational signature of diffuse large B-cell lymphomas according to the primary organ.

BACKGROUND: Comprehensive molecular subtyping of diffuse large B-cell lymphoma (DLBCL) through genetic profiling has broadened our understanding of DLBCL biology. In this study, we investigated whether DLBCL, not otherwise specified (NOS) shows differences in mutational patterns depending on the primary organ. PATIENTS AND METHODS: Panel-based next-generation sequencing was performed on 345 DLBCL from various primary organs, and patterns of mutations according to primary organs were analyzed. RESULTS: DLBCL showed a characteristic mutational signature in several primary organs. Among them, the mutational pattern of DLBCL in the breast and ileocecal area was particularly different from that of other DLBCL NOS. In breast DLBCL, MYD88L265P (57.1%), CD79B mutation (42.9%), and CDKN2A/B loss (71.4%) were found at high frequencies, which were similar to the mutation patterns of DLBCL of immune-privileged sites compared with DLBCL NOS. DLBCL in the ileocecal area showed a characteristic mutation pattern with the most frequent TP53 mutation (52.6%) and 18q21 gain (42.1%). This was also different from the mutational pattern observed in the stomach or other intestines. In discriminant analysis, DLBCL of the breast and ileocecal area tended to form separate genetic constellations from other DLBCL NOS. CONCLUSION: DLBCL NOS has a characteristic mutational profile that depends on the primary organ. In particular, the mutational signature of DLBCL in the breast and ileocecal area was heterogeneous compared with that of other DLBCL NOS. Further research is needed to determine whether primary DLBCL in the breast and ileocecal area can be classified as an independent subtype.

Mesonephric-like Adenocarcinoma of the Uterine Corpus: Genomic and Immunohistochemical Profiling with Comprehensive Clinicopathological Analysis of 17 Consecutive Cases from a Single Institution.

Data on genetic and immunophenotypical characteristics of uterine mesonephric-like adenocarcinoma (MLA) remain limited. Therefore, we aimed to investigate the clinicopathological, immunohistochemical, and molecular features of uterine MLA. We performed targeted sequencing, array comparative genomic hybridization, and immunostaining in 17, 13, and 17 uterine MLA cases, respectively. Nine patients developed lung metastases. Eleven patients experienced disease recurrences. The most frequently mutated gene was Kirsten rat sarcoma viral oncogene homolog (KRAS; 13/17). Both the primary and matched metastatic tumors harbored identical KRAS (3/4) and phosphatase and tensin homolog deleted on chromosome 10 (1/4) mutations, and did not harbor any additional mutations. A total of 2 of the 17 cases harbored tumor protein 53 (TP53) frameshift insertion and deletion, respectively. Chromosomal gains were detected in 1q (13/13), 10 (13/13), 20 (10/13), 2 (9/13), and 12 (6/13). Programmed cell death-ligand 1 overexpression or mismatch repair deficiency was not observed in any of the cases. Initial serosal extension and lung metastasis independently predicted recurrence-free survival with hazard ratios of 6.30 and 7.31, respectively. Our observations consolidated the clinicopathological and molecular characteristics of uterine MLA. Both clinicians and pathologists should consider these features to make an accurate diagnosis of uterine MLA and to ensure appropriate therapeutic management of this rare entity.

Loss of F-Box and Leucine Rich Repeat Protein 5 (FBXL5) Expression Is Associated With Poor Survival in Patients With Hepatocellular Carcinoma After Curative Resection: A Two-institute Study.

BACKGROUND/AIM: Alteration of F-box and leucine-rich repeat protein 5 (FBXL5), an iron-sensing ubiquitin ligase, might be related with carcinogenesis of hepatocellular carcinoma (HCC), by disturbing cellular iron homeostasis. However, the clinical implications of FBXL5 expression using patient samples need to be elucidated. PATIENTS AND METHODS: We collected HCC tissue samples from two institutes: Samsung Medical Center (n=259) and Hallym University Sacred Heart Hospital (n=115) and evaluated FBXL5 expression using immunohistochemistry. Using cut-off values determined by X-tile software, association between FBXL5 expression and several clinicopathological parameters was investigated. For external validation, the Cancer Genome Atlas (TCGA) cohort was used. RESULTS: The best cutoff value for FBXL5 IHC expression associated with recurrence-free survival (RFS) was 5%. Low FBXL5 expression was found in 18.7% of the total 374 HCCs and was associated with non-viral etiology (p=0.019). Low FBXL5 expression was related with inferior disease-specific survival (DSS, p=0.002) and RFS (p=0.001) and also was an independent prognostic factor for DSS and RFS. In addition, cases with low FBLX5 mRNA levels showed inferior DSS and RFS (p<0.001 and p=0.002, respectively) compared to high FBLX5 mRNA levels in the TCGA cohort. CONCLUSION: Down-regulation of FBXL5 expression in HCCs might be associated with poor prognosis. FBXL5 might be a prognostic biomarker of HCCs and a potential therapeutic target in conjunction with iron homeostasis.

Papillary and medullary thyroid carcinomas coexisting in the same lobe, first suspected based on fine-needle aspiration cytology: a case report.

Because different types of thyroid malignancies have distinct embryological origins, coexisting tumors are rarely observed. We describe a coexisting papillary thyroid carcinoma (PTC) and medullary thyroid carcinoma (MTC) first suspected by fine-needle aspiration cytology (FNAC). A 57-year-old female presented with an irregular mass in the right thyroid lobe. The cytopathologic findings of fine-needle aspiration showed two components: a papillary-like arrangement consisting of cells with pale enlarged nuclei indicative of PTC and loose clusters comprised of oval cells with granular chromatin indicative of MTC. The diagnosis of a coexisting PTC and MTC was initially confirmed by calcitonin immunocytochemistry and later after total thyroidectomy. Although some surgical case reports of PTC and MTC coexisting in either the same or different lobes have been documented, a case suspected by FNAC before the surgery has rarely been reported. Because appropriate treatment and prognosis of PTC and MTC are different, cytopathologists should be aware of this rare entity.

Unearthing novel fusions as therapeutic targets in solid tumors using targeted RNA sequencing.

Detection of oncogenic fusion genes in cancers, particularly in the diagnosis of uncertain tumors, is crucial for determining effective therapeutic strategies. Although novel fusion genes have been discovered through sequencing, verifying their oncogenic potential remain difficult. Therefore, we evaluated the utility of targeted RNA sequencing in 165 tumor samples by identifying known and unknown fusions. Additionally, by applying additional criteria, we discovered eight novel fusion genes that are expected to process oncogenicity. Among the novel fusion genes, RAF1 fusion genes were detected in two cases. PTPRG-RAF1 fusion led to an increase in cell growth; while dabrafenib, a BRAF inhibitor, reduced the growth of cells expressing RAF1. This study demonstrated the utility of RNA panel sequencing as a theragnostic tool and established criteria for identifying oncogenic fusion genes during post-sequencing analysis.

Mesonephric-like Adenocarcinoma of the Ovary: Clinicopathological and Molecular Characteristics.

Mesonephric-like adenocarcinoma (MLA) arising in the ovary is a rare malignant tumor of the female genital tract. Although the clinicopathological and molecular characteristics of uterine MLA have been accumulated, those of ovarian MLA have not been firmly clarified. In this study, we investigated the clinicopathological, immunohistochemical, and genetic features of five ovarian MLAs. A review of electronic medical records and pathology slides, immunostaining, and targeted sequencing was performed. On imaging, ovarian MLA presented as either a mixed solid and cystic mass or a purely solid mass. One, three, and one patient were diagnosed as having FIGO stage IA, IC, and II MLA, respectively. Four patients with stage IC-II tumor underwent post-operative adjuvant chemotherapy. Three of the four patients whose follow-up information was available did not experience recurrence. In contrast, the remaining patient with stage IA tumor who did not receive any adjuvant treatment developed multiple metastatic recurrences at post-operative 13 months. Histologically, ovarian MLAs characteristically displayed architectural diversity, compactly aggregated small tubules, and eosinophilic intraluminal secretions. Four tumors were found to be associated with endometriotic cysts. Two cases showed some areas of high-grade nuclear atypia, brisk mitotic activity, and necrosis. Immunohistochemically, all cases showed positive immunoreactivities for at least three of the four examined mesonephric markers (GATA3, PAX2, TTF1, and CD10), lack of WT1 expression, non-diffuse p16 immunoreactivity, and wild-type p53 immunostaining pattern. Targeted sequencing analysis revealed that all four examined cases harbored pathogenic KRAS mutations: p.G12V (2/4); p.G12D (1/4); and p.G12C (1/4). In addition, we reviewed the previous literature reporting 60 cases of ovarian MLA. Our findings corroborate those of the previous data regarding the clinical presentation, histological features, immunophenotypes, and molecular alterations. Our observations should encourage pathologists to recognize and accurately diagnose this rare but distinct entity.

Down-regulation of TRPV6 Is Associated With Adverse Prognosis in Hepatocellular Carcinoma Treated With Curative Resection.

BACKGROUND/AIM: Transient receptor potential vanilloid 6 (TRPV6), an endothelial Ca2+-selective entry channel, is expressed in various cancer types, and a selective TRPV6 inhibitor is currently being investigated in a clinical trial. However, TRPV6 expression in hepatocellular carcinoma (HCC) has not been reported. MATERIALS AND METHODS: We evaluated TRPV6 expression in 219 cases of HCC and analyzed its association with clinicopathological parameters and prognostic significance. TRPV6 mRNA expression was compared between HCC and non-tumor liver tissues using various public datasets, and its prognostic effect was examined in The Cancer Genome Atlas (TCGA) cohort. RESULTS: Low TRPV6 expression was found in 37.4% of patients, which was significantly associated with adverse histologic features, and patients with low TRPV6 expression had shorter recurrence-free and disease-free survival. TRPV6 mRNA expression was consistently lower in HCC compared to non-tumor liver samples in public datasets, at the whole tissue level as well as single-cell level. Patients with low TRPV6 expression in the TCGA cohort had shorter progression-free survival. CONCLUSION: TRPV6 expression is down-regulated in HCCs and associated with a poor prognosis. TRPV6 may be a prognostic biomarker in HCC.

Validation of ZMYND8 as a new treatment target in hepatocellular carcinoma.

BACKGROUND: ZMYND8 (Zinc finger MYND (Myeloid, Nervy and DEAF-1)-type containing 8) has been known to play an important role in tumor regulation in various types of cancer. However, the results of ZMYND8 expression and their clinical significance in hepatocellular carcinoma (HCC) have not yet been published. In the present study, we investigate the expression of ZMYND8 protein and mRNA in HCC and elucidate its prognostic significance. METHODS: ZMYND8 protein and mRNA expression in 283 and 234 HCCs were investigated using immunohistochemistry and microarray gene expression profiling data. The relationships between ZMYND8 expression with clinicopathologic features and prognosis of HCC patients were evaluated. Furthermore, we performed the invasion, migration, apoptosis, soft agar formation assay and sphere formation assay in HCC cell lines, and evaluated tumorigenicity in a nude mouse model, after ZMYND8 knockdown. RESULTS: Overexpression of ZMYND8 protein and mRNA was observed in 20.5% and 26.9% of HCC cases, respectively. High ZMYND8 expression showed significant correlations with microvascular invasion, high Edmondson grade, advanced American Joint Committee on Cancer, and increased alpha-fetoprotein level. ZMYND8 mRNA overexpression was an independent prognostic factor for predicting early recurrence as well as short recurrence-free survival (RFS). Downregulation of ZMYND8 reduced migration and invasion of HCC cells, and promoted apoptosis of HCC cells in an in vitro model. In a xenograft nude mouse model, knockdown of ZMYND8 significantly reduced tumor growth. CONCLUSION: ZMYND8 mRNA overexpression could be a prognostic marker of shorter RFS in HCC patients after curative resection. ZMYND8 might play an important role in the proliferation and progression of HCC and could be a promising candidate for targeted therapy.

Clinicopathological Characteristics of Gastric-type Endocervical Adenocarcinoma Misdiagnosed as an Endometrial, Ovarian or Extragenital Malignancy, or Mistyped as Usual-type Endocervical Adenocarcinoma.

BACKGROUND/AIM: The diagnosis of gastric-type endocervical adenocarcinoma (GEA) is challenging because its differential diagnosis includes not only gynecological tumors, but also extragenital tumors. PATIENTS AND METHODS: We reviewed the electronic medical records and all available slides to investigate the clinicopathological characteristics of eight misdiagnosed GEA cases. RESULTS: Three tumors were initially misdiagnosed as endometrial carcinoma. They displayed extensive endomyometrial involvement and complex glandular architecture, but no severe nuclear pleomorphism. Another three tumors were misclassified as usual-type endocervical adenocarcinoma because of mucin-poor, pseudoendometrioid glands, apical mitotic figures, and karyorrhectic debris. The two remaining tumors presenting as adnexal masses mimicked primary ovarian mucinous tumor and metastatic cholangiocarcinoma. CONCLUSION: The varying pathological characteristics of GEA reflect the variability in clinical manifestations and its diagnostic difficulties. It is challenging to make an accurate diagnosis based solely on histological features. When suspecting GEA, clinicians should consider more comprehensively the clinicopathological context, along with immunostaining results.

Clinicopathological Characteristics of Squamous Cell Carcinoma and High-grade Squamous Intraepithelial Lesions Involving Endocervical Polyps.

BACKGROUND/AIM: To investigate the clinicopathological characteristics of high-grade squamous intraepithelial lesions (HSILs) and squamous cell carcinomas (SCCs) involving endocervical polyps (ECPs). PATIENTS AND METHODS: We collected the endocervical polypectomy cases and performed pathological examination and cytohistological correlation. RESULTS: During a period of 12 years, 21 (1.1%) HSILs and two (0.1%) SCCs involving ECPs were identified in 1,905 cases. Twelve (63.1%) of the 19 cases were cytohistologically concordant. In five HSILs and one SCC with polypectomy margin involvement, residual HSIL was identified in conization or hysterectomy specimens. Furthermore, in two HSIL patients and one SCC patient with negative polypectomy margins, residual HSILs were found in the conization specimens. CONCLUSION: The prevalence of HSIL and SCC involving ECP in our cohort was similar to the rates found in previous studies. The presence of residual HSIL in nonpolypoid cervical tissue regardless of the polypectomy margin involvement suggests that conization or hysterectomy is needed for diagnostic or treatment purposes.

Impact of Implementing the Paris System for Reporting Urinary Cytology: A Single-institutional Experience With Emphasis on Diagnostic Yield of High-grade Urothelial Carcinoma and Low-grade Urothelial Neoplasm.

BACKGROUND/AIM: The Paris System (TPS) has recently been proposed as a method to standardize urinary cytology reporting. In this study, we evaluated the impact of implementing TPS compared to the traditional reporting system. PATIENTS AND METHODS: In total, 299 urine samples were reclassified according to TPS. We examined correlations between cytological and histological diagnoses, and calculated probabilities for detecting high-grade urothelial carcinoma (HGUC). RESULTS: TPS resulted in a decrease in the proportion of cases diagnosed as atypical urothelial cell (AUC) (43% to 31%). Among the AUC cases, the proportion of histologically confirmed HGUC cases rose (75% to 80%), as did the proportion of low-grade urothelial neoplasms (57% to 71%). All probabilities for detecting HGUC significantly increased using TPS. CONCLUSION: TPS improved the diagnostic yield of urinary cytology. The implementation of TPS is expected to be a major step towards standardizing urinary cytology reporting and providing clear information to clinicians.

Invasive Micropapillary Carcinoma of the Uterine Cervix.

We herein present a case of uterine cervical invasive micropapillary carcinoma (IMPC) in a 35-year-old woman. She had neither specific symptoms nor any previous gynecological history. A cervical punch biopsy revealed a high-grade squamous intraepithelial lesion and concurrent intestinal-type mucinous carcinoma. Based on the preoperative diagnosis of endocervical adenocarcinoma, she underwent radical hysterectomy with bilateral salpingo-oophorectomy and bilateral pelvic lymph node dissection. Grossly, there was an ovoid, slightly elevated mass with surface nodularity in the lower endocervix, measuring 10 × 8 mm. Histologically, the tumor consisted predominantly of tufts of tumor cells arranged in micropapillary structures devoid of fibrovascular cores and surrounded by clear, empty, lacunar spaces between tumor cell nests and stroma. The IMPC component comprised 90% of the entire tumor volume. The greatest dimension and stromal invasion depth of the IMPC were 8 and 3 mm, respectively (FIGO stage IA2). Immunostaining revealed that mucin 1 (MUC1) surrounded each micropapillary structure, indicating the reverse epithelial polarity of the glandular cells. MUC1 was localized predominantly in the stroma-facing surface of the cell clusters, accentuating the outlines of the micropapillary structures by forming a distinct, characteristic band on this surface. In addition, targeted sequencing analysis of the IMPC revealed a missense PIK3CA mutation (c.1633G>A). In summary, we present the clinicopathological characteristics of cervical IMPC. We demonstrate for the first time that IMPC of the uterine cervix harbors a pathogenic missense mutation in PIK3CA. Further investigations using larger cohorts of patients are necessary to confirm these findings.

Pathologic analyses of peritoneal nodules in gastric cancer patients during surgery-A single cancer center experience with diagnostic pitfalls.

BACKGROUND: Gastric carcinoma (GC) is the second most common cause of cancer-related deaths worldwide. During operations, nodular lesions of the peritoneum are often sent for frozen section (FS). For pathologists, FS of the peritoneum is challenging due to sparse and discohesive tumor cells in a fibrotic background. METHODS: To explore diagnostic accuracy and diagnostic pitfalls of FS in this setting, we retrospectively collected 252 peritoneal biopsies in cases with GC from January 2006 to May 2017 and compared corresponding permanent sections and patient prognosis. After review, 6 cases (2.4%) were discrepant: positive conversion was identified in 5 cases due to scarce tumor cells associated with severe fibrosis and inflammation; negative conversion was identified in one case due to papillary mesothelial cell proliferation masquerading as carcinoma. RESULTS: Two hundred cases were finally confirmed as positive for tumor cells. Of these, 185 (92.5%) patients died of GC, with survival times ranging from 7 to 3574 (mean 415) days after operation. Fifty-two (20.6%) cases were negative for tumor, and pathologic findings included chronic inflammation with fibrosis (N = 25: associated with previous operation, 10; idiopathic, 15) and papillary mesothelial cell proliferation (N = 9). All 5 patients with frozen diagnosis converted to positive results died of GC during follow up. A total of 19 patients with peritoneal nodules diagnosed as benign on FS died with GC (79.0%), and their survival times ranged from 87 to 3649 (mean 833) days. CONCLUSIONS: Peritoneal biopsies in patients with GC were mostly carcinoma, followed by chronic inflammation with fibrosis and papillary mesothelial cell proliferation. Deeper sections or intradepartmental consultations were helpful to reduce false negative diagnosis on FS.

Pulmonary Nodular Lymphoid Hyperplasia with Mass-Formation: Clinicopathologic Characteristics of Nine Cases and Review of the Literature.

BACKGROUND: Pulmonary nodular lymphoid hyperplasia (PNLH) is a non-neoplastic pulmonary lymphoid disorder that can be mistaken for malignancy on radiography. Herein, we present nine cases of PNLH, emphasizing clinicoradiological findings and histological features. METHODS: We analyzed radiological and clinicopathological features from the electronic medical records of nine patients (eight females and one male) diagnosed with PNLH. IgG and IgG4 immunohistochemical staining was performed in three patients. RESULTS: Two of the nine patients had experienced tuberculosis 40 and 30 years prior, respectively. Interestingly, none were current smokers, although two were ex-smokers. Three patients complaining of persistent cough underwent computed tomography of the chest. PNLH was incidentally discovered in five patients during examination for other reasons. The remaining patient was diagnosed with the disease following treatment for pneumonia. Imaging studies revealed consolidation or a mass-like lesion in eight patients. First impressions included invasive adenocarcinoma and mucosal-associated lymphoid tissue‒type lymphoma. Aspergillosis was suspected in the remaining patient based on radiological images. Resection was performed in all patients. Microscopically, the lesions consisted of nodular proliferation of reactive germinal centers accompanied by infiltration of neutrophils and macrophages in various degrees and surrounding fibrosis. Ultimately, all nine patients were diagnosed with PNLH and showed no evidence of recurrence on follow-up. CONCLUSIONS: PNLH is an uncommon but distinct entity with a benign nature, and understanding the radiological and clinicopathological characteristics of PNLH is important.