Significance of interstitial fibrosis and p16 in papillary thyroid carcinoma

Diffuse expression of p16 in pancreatic neuroendocrine tumors (PanNETs) and the association of morphology variants

OBJECTIVE

Distinguishing grade 3 pancreatic neuroendocrine tumors (PanNETs) from neuroendocrine carcinomas (PanNECs) is sometimes challenging. Recently, a diffuse p16-positive pattern was reported in PanNECs but not in grade 3 PanNETs, suggesting that p16 could help differentiate these entities. This study aimed to investigate p16 expression in PanNETs of various grades and its association with clinicopathologic features.

METHODS

A total of 114 PanNETs were selected, and their H&E resection slides were reviewed for pathologic features, with a focus on morphologic variants. Tissue microarrays were constructed, and p16 immunohistochemistry was performed. The results were categorized as diffuse positive, partial positive, or negative. Patient electronic health records were reviewed for follow-up data.

RESULTS

Among the 114 PanNETs reviewed, 13 (11.4%) exhibited diffuse p16 expression, 40 (35.1%) were negative, and 61 (53.5%) had partial expression. Diffuse p16 expression occurred in 6 of 38 (15.8%) grade 1, 6 of 60 (10.0%) grade 2, and 1 of 16 (6.3%) grade 3 tumors. Expression did not differ substantially with patient demographics, tumor size, grading, staging, or survival, but diffuse p16 expression was more frequent in body/tail tumors (12/65 [18.5%], P = .019) and in stromal-rich tumors (10/23 [43.5%], P < .001).

CONCLUSIONS

Diffuse p16 expression is not uncommon in PanNETs and may be associated with stroma-rich variants.

Prognostic impact of fibrosclerotic changes in non-papillary, non-anaplastic, follicular cell-derived thyroid carcinomas

In non-papillary follicular cell-derived thyroid carcinomas, prognostic factors are scarce. Intratumoral fibrosis was identified as an adverse factor in papillary and medullary carcinomas, but it has not been investigated in other subtypes. We aimed at exploring the presence of intratumoral fibrosclerosis in a cohort of 132 non-papillary follicular cell-derived thyroid carcinomas (53 follicular and 31 oncocytic carcinomas, including 10 high grade differentiated thyroid carcinomas and 48 poorly differentiated carcinomas) and correlating its presence and extent with clinical and pathological features and survival. For each case, all available hematoxylin and eosin slides were reviewed, and the presence of fibrosclerosis was assessed as the percentage of tumor area and semi-quantitatively scored as absent, mild (≤ 10%) or extensive (> 10%). In addition, digital image analysis was applied in 65 cases. Scoring of intratumoral fibrosis showed a strong agreement between two observers and between observers and digital image quantification. The presence and extent of intratumoral fibrosis were significantly associated with poorly differentiated carcinoma histology, large tumor size, extent of vascular invasion, presence of necrosis, high mitotic index, positive nodal status, and aggressive clinical outcome, and with a shorter disease-free and disease-specific survival, the former also in follicular and oncocytic carcinomas analyzed separately. These data support the potential use of fibrosis in the clinical practice since it is both easily assessable and significantly associated with the presence of parameters of aggressiveness. In addition, fibrosis is correlated with decreased survival rate independently from the tumor histotypes, suggesting its potential role as novel prognostic factor in non-papillary follicular cell-derived thyroid carcinomas.

Histopathological Analysis of Thyroid Nodules with Taller-Than-Wide Shape in Adults

Background

The ultrasound examination (USE) feature of taller-than-wide (TTW) shape is highly specific but low sensitive in diagnosis of thyroid carcinoma. Relationships between other USE malignant features (such as irregular margin, ill-defined, markedly hypoechoic, and microcalcification) with histopathological features have been well investigated, while studies about the histopathologic features of TTW shape are rare.

Aim

The present study aimed to investigate the histopathological features of thyroid nodules with TTW shapes.

Methods

A total of 85 thyroid nodules with TTW were selected from 1680 consecutive patients who underwent thyroid resection. USE features of the nodules, including size, location, boundary, margin, composition, echogenicity, and calcification, were recorded according to the China Thyroid Imaging Reporting and Data System (C-TIRADS). Hypoechoic lesions were further categorized as mild, moderate or markedly hypoechoic lesions. The histological features of the specimens were evaluated according to the arrangement of follicular cells, presence of papillary structures or psammoma bodies, degree of fibrosis, and amount of lymphoid infiltration. Differences in the USE and histological features between benign and malignant nodules were compared.

Results

Among the 85 nodules, 72 (84.71%) were malignant, and 13 (15.29%) were benign. Only echogenicity showed a statistically significant difference between benign and malignant nodules (P=0.003). Apart from microfoci, papillary structures, and psammoma bodies, the degree of fibrosis was also significantly different between benign and malignant tumors (all P<0.05). Regression analysis showed a trend of decreasing nodule echogenicity with increasing fibrosis frequency (odds ratio [OR] = 4.500).

Conclusion

Extensive fibrosis is the most common histopathological feature of thyroid cancer and corresponds to hypoechogenicity in USE. TTW-shaped thyroid nodules are highly suggestive of malignancy, especially those with moderate or markedly hypoechogenicity.

Thyroid hemiatrophy associated with papillary thyroid carcinoma

PURPOSE

The present study aimed to investigate CT imaging features, pathological findings, and prognosis in patients with thyroid hemiatrophy (THA) associated with papillary thyroid carcinoma (PTC).

METHODS

This retrospective study included 225 patients with histopathologically proven PTC treated by surgical resection who underwent preoperative CT scanning. On CT images, THA was defined as thyroid parenchymal hemiatrophy on the ipsilateral side of PTC. CT findings, overall survival, and disease-free survival were compared between patients with and without THA. Pathological findings were also assessed in PTCs with and without THA.

RESULTS

THA was observed in 35 of 225 (16%) patients with PTC. Atrophic thyroid parenchyma was observed in the right lobe of 20 patients (57%) and in the left lobe of the remaining 15 patients (43%). With respect to the solid components within PTCs, contrast-enhanced CT attenuation (114.2 ± 18.2 vs. 126.7 ± 31.3 HU; p < 0.05) and CT attenuation change for contrast-enhanced CT minus unenhanced CT (60.2 ± 18.1 vs. 72.3 ± 31.0 HU; p < 0.05) were significantly lower in PTCs with THA than in those without THA. Histopathologically, almost all PTCs with THA (97%) had keloid-like collagen, which is broad bundles of hypocellular collagen with bright eosinophilic hyalinization, typically observed in keloid. However, no significant differences were observed in the prognosis between the two groups.

CONCLUSION

THA was occasionally observed in patients with PTC. Weak contrast-enhancement was distinct characteristic of PTC patients with THA, which is probably caused by keloid-like collagen.

Interstitial Fibrosis as a Common Counterpart of Histopathological Risk Factors in Papillary Thyroid Microcarcinoma: A Retrospective Analysis

PURPOSE

Interstitial fibrosis in papillary thyroid microcarcinoma is a subject which is under-investigated. The aim of this study is to determine the relationship between interstitial fibrosis, the subtypes of papillary microcarcinoma, and the established prognostic factors.

MATERIAL AND METHODS

A total of 75 patients diagnosed with papillary microcarcinoma of the thyroid from January 2011 to December 2020 have been evaluated retrospectively, using demographic features, tumor size, subtype of the tumor, surgical margin status, unifocality, lymphovascular invasion, extracapsular spread and lymph node metastasis as parameters. Hematoxylin and eosin slides were reviewed for interstitial fibrosis.

RESULTS

The study includes 13 males and 62 females, in a total of 75 patients. There were 51 patients (68%) with interstitial fibrosis and 24 (32%) patients without interstitial fibrosis. Among them, 45 (60%) were classic, 27 (36%) were follicular variant and 3 (4%) were other subtypes. Interstitial fibrosis is significantly associated with bilaterality (p = 0.023), multifocality (p = 0.004), capsule invasion (p < 0.001) and lymph node metastasis (p = 0.043). Evaluation of tumor sub groups showed significant increased risk of lymphovascular invasion in the follicular variant (p = 0.019).

CONCLUSION

Although the relationship of interstitial fibrosis and prognosis of other cancer types has been discussed, there are few studies in the literature regarding its effect on the prognosis of papillary microcarcinoma. Our results show that interstitial fibrosis can be used as a risk factor. However, new studies are needed to clearly reveal the physiopathology of interstitial fibrosis and its effect on tumorigenesis.

Comprehensive analysis of cellular senescence and immune microenvironment in papillary thyroid carcinoma

Senescence-induced therapy was previously considered as an effective treatment for tumors, and cellular senescence was initially regarded as an effective mechanism against cancer. However, whether cell senescence-related genes can be used to predict the prognosis of papillary thyroid carcinoma (PTC) and immunotherapy remains unclear. We developed and validated a cell senescence-related signature (CSRS) by analyzing the gene expression of 278 genes related to cellular senescence in 738 patients with PTC. Additionally, further analysis showed that CSRS was a reliable predictor of patient outcomes in combination with immune checkpoint expression and drug susceptibility, and patients with high risk scores may benefit from immunotherapy. The findings of this study demonstrate that CSRS serves as an immunotherapeutic response and prognosis biomarker affecting the tumor immune microenvironment of PTC.

A comprehensive analysis of tumor-stromal collagen in relation to pathological, molecular, and immune characteristics and patient survival in pancreatic ductal adenocarcinoma

BACKGROUND

Abundant collagen deposition is a hallmark of pancreatic ductal adenocarcinomas (PDACs). This study clarified the interactive relationship between tumor-stromal collagen, molecular and immune characteristics, and tumor pr ogression in human PDAC.

METHODS

We performed a comprehensive examination using an integrative molecular pathological epidemiology database on 169 cases with resected PDAC . The amount of tumor-stromal collagen was quantified through digital imaging analysis for Elastica van Gieson-stained whole-section tumor slides. We analyzed the association of tumor-stromal collagen with gene alterations (KRAS, TP53, CDKN2A/p16, and SMAD4), immune parameters (CD4+ tumor-infiltrating lymphocytes [TILs], CD8+ TILs, FOXP3+ TILs, and tertiary lymphoid structures), and patient prognosis.

RESULTS

Low amounts of tumor-stromal collagen were associated with poor differentiation (multivariable OR = 3.82, 95%CI = 1.41-12.2, P = 0.008) and CDKN2A/p16 alteration (OR [95%CI] = 2.06 [1.08-4.02], P = 0.03). Tumors with low collagen levels had shorter overall survival (HR [95%CI] = 2.38 [1.59-3.56], P < 0.0001). In the S-1 and gemcitabine (GEM) treatment groups, low tumor-stromal collagen was linked to poor prognosis of patients with PDAC (S-1 group: multivariable HR [95%CI] = 2.76 [1.36-5.79], P = 0.005; GEM group: multivariate HR [95%CI] = 2.91 [1.34-6.71], P = 0.007). Additionally, low amounts of tumor-stromal collagen were also linked to low levels of CD4+ TILs (P = 0.046), CD8+ TILs (P = 0.09), and tertiary lymphoid structures (P = 0.001).

CONCLUSIONS

Tumor-stromal collagen deposition may play a crucial role in modulating tumor-immune microenvironment and determining response to adjuvant chemotherapy and patient survival outcomes.

Clinical and Pathological Features and Gene Expression Profiles of Clinically Aggressive Papillary Thyroid Carcinomas

Papillary thyroid carcinoma (PTC) is considered an indolent neoplasm but it may demonstrate aggressive behavior. We aimed to identify clinical and pathological characteristics and molecular signatures associated with aggressive forms of PTCs. We selected 43 aggressive PTC cases based on the presence of metastases at the time of diagnosis, the development of distant metastasis during follow-up, and/or biochemical recurrence, and 43 PTC patients that were disease-free upon follow-up, matching them according to age, sex, pT, and pN parameters. Twenty-four pairs (a total of 48 cases) and 6 normal thyroid tissues were studied using targeted mRNA screening of cancer-associated genes employing NanoString nCounter® technology. In general, aggressive PTCs showed distinctive clinical and morphological features. Among adverse prognostic parameters, the presence of necrosis and an increased mitotic index were associated with shorter disease-free and overall survivals. Other parameters associated with shorter disease-free or overall survivals include a lack of tumor capsule, the presence of vascular invasion, tumor-infiltrating lymphocytes, fibrosclerotic changes, age > 55 years, and a high pTN stage. Various pathways were differentially regulated in non-aggressive as compared to aggressive PTC, including the DNA damage repair, the MAPK, and the RAS pathways. In particular, the hedgehog pathway was differentially de-regulated in aggressive PTC as compared to non-aggressive PTC cases, being WNT10A and GLI3 genes significantly up- and down-regulated in aggressive PTC and GSK3B up-regulated in non-aggressive PTC cases. In conclusion, our study revealed specific molecular signatures and morphological features in aggressive PTC that may be useful to predict more aggressive behavior in a subset of PTC patients. These findings may be useful when developing novel, tailored treatment options for these patients.