Grading medullary thyroid carcinoma on fine-needle aspiration cytology specimens with the International Medullary Thyroid Carcinoma Grading System: A cytologic-histologic correlation

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare cancer of parafollicular C-cell origin. The International MTC Grading System (IMTCGS) incorporates mitotic activity, the presence of necrosis, and the Ki67 proliferation rate (PR) to classify MTCs as low or high grade. The ability to predict IMTCGS grade in cytology was assessed.

METHODS

MTCs with cytology and subsequent surgical follow-up were reviewed. Cytology slides were reviewed for mitotic figures, apoptoses, and necrosis, and a Ki67 PR was calculated when possible. Findings were correlated with final IMTCGS grade.

RESULTS

Twenty-five MTC fine-needle aspirations (FNAs) were identified, with nine identified as high grade (36%). By using a PR cutoff of 5%, Ki67 on FNA material (Ki67FNA) showed 92% concordance (n = 22 of 24) with surgical Ki67 and a correlation coefficient (R2) of 0.72. Sensitivity and specificity of Ki67FNA for predicting high-grade MTC were 38% and 100%, respectively. Multiple mitotic figures were present in a single slide of 43% (n = 3 of 7) of evaluable high-grade MTCs, whereas only one of 16 low-grade MTCs showed a single mitotic figure. Definitive apoptoses were present in five of seven high-grade MTC FNAs but were absent in 16 low-grade MTCs. The sensitivity and specificity of apoptoses/necrosis on cytology for high-grade MTCs were 71% and 88%, respectively.

CONCLUSIONS

Ki67FNA ≥5% shows low sensitivity but high specificity for predicting high-grade MTC. The presence of multiple mitotic figures in a single slide or definitive apoptotic bodies are both highly suggestive of high-grade MTC, and should warrant a close examination for necrosis and a careful Ki67 PR count.

Accuracy of World Health Organisation-grade parameters (necrosis and mitotic activity) and foci of vascular invasion in predicting prognosis of papillary thyroid carcinoma. A case-control validation study

AIMS

Tumour necrosis and/or increased mitoses define high-grade papillary thyroid carcinoma (PTC). It is unclear whether angioinvasion is prognostic for PTC. Cut-offs at five or more mitoses/2 mm2 and four or more angioinvasive foci have been empirically defined based upon data from all forms of aggressive non-anaplastic thyroid carcinomas. Performance of tumour necrosis, mitoses and vascular invasion in predicting distant metastases when specifically applied to PTC is undefined.

METHODS

We analysed 50 consecutive PTC cases with distant metastases (DM-PTC): 16 synchronous and 34 metachronous. A total of 108 non-metastatic PTC (N-DM-PTC, 15.0-year median follow-up) were used as controls. Invasive encapsulated follicular variant PTC was excluded. Necrosis, mitoses and angioinvasion were quantified. Receiver operating characteristics (ROC) and area under the curve (AUC) analyses determined best sensitivity and specificity cut-offs predictive of distant metastases.

RESULTS

Metastases correlated with necrosis (any extent = 43.8% all DM-PTC, 53.1% metachronous DM-PTC versus 5% N-DM-PTC; P < 0.001), mitoses (P < 0.001) and angioinvasion (P < 0.001). Mitoses at five or more per 2 mm2 was the best cut-off correlating with distant metastases: sensitivity/specificity 42.9%/97.2% all DM-PTC (AUC = 0.78), 18.8%/97.2% synchronous DM-PTC (AUC = 0.63), 54.6%/97.2% metachronous DM-PTC (AUC = 0.85). Angioinvasive foci at five or more was the best cut-off correlating with distant metastases: sensitivity/specificity 36.2%/91.7% all DM-PTC (AUC = 0.75), 25%/91.7% synchronous DM-PTC (AUC = 0.79) and 41.9%/91.7% metachronous DM-PTC (AUC = 0.73). Positive/negative predictive values (PPV/NPV) were: necrosis 22.6%/98.2%; five or more mitoses 32.3%/98.2%; five or more angioinvasive foci 11.8%/97.9%. After multivariable analysis, only necrosis and mitotic activity remained associated with DM-PTC.

CONCLUSION

Our data strongly support PTC grading, statistically validating World Health Organisation (WHO) criteria to identify poor prognosis PTC. Angioinvasion is not an independent predictor of DM-PTC.

A threshold for mitotic activity and post-surgical residual volume defines distinct prognostic groups for astrocytoma IDH-mutant

AIMS

The distinction between CNS WHO grade 2 and grade 3 is instrumental in choosing between observational follow-up and adjuvant treatment for resected astrocytomas IDH-mutant. However, the criteria of CNS WHO grade 2 vs 3 have not been updated since the pre-IDH era.

METHODS

Maximal mitotic activity in consecutive high-power fields corresponding to 3 mm2 was examined for 118 lower-grade astrocytomas IDH-mutant. The prognostic value for time-to-treatment (TTT) and overall survival (OS) of mitotic activity and other putative prognostic factors (including age, performance status, pre-surgical tumour volume, multilobar involvement, post-surgical residual tumour volume and midline involvement) was assessed for tumours with ATRX loss and the absence of CDKN2A homozygous deletion or CDK4 amplification, contrast enhancement, histological necrosis and microvascular proliferation.

RESULTS

Seventy-one per cent of the samples had <6 mitoses per 3 mm2 . Mitotic activity, residual volume and multilobar involvement were independent prognostic factors of TTT. The threshold of ≥6 mitoses per 3 mm2 identified patients with a shorter TTT (median 18.5 months). A residual volume ≥1 cm3 also identified patients with a shorter TTT (median 24.5 months). The group defined by <6 mitoses per 3 mm2 and a residual volume <1 cm3 had the longest TTT (median 73 months) and OS (100% survival at 7 years). These findings were confirmed in a validation cohort of 52 tumours.

CONCLUSIONS

Mitotic activity and post-surgical residual volume can be combined to evaluate the prognosis for patients with resected astrocytomas IDH-mutant. Patients with <6 mitoses per 3 mm2 and a residual volume <1 cm3 were the best candidates for observational follow-up.

Gastric neuroendocrine neoplasms and precursor lesions: Case reports and literature review

RATIONALE

Gastric neuroendocrine neoplasms (g-NENs) represent a distinctive group of gastric tumors, stratified into different prognostic categories according to different histological characteristics, put forth in the 2018 World Health Organization classification system. The clinical presentations, as well as pathological features, represent important data in establishing the type of the tumor, in estimating the tumor behavior, and in selecting the best therapeutic strategy. In our case series we presented different clinical scenarios that may be encountered in practice regarding gastric NENs. We performed a literature review and discussed diagnostic strategy, current classification system, precursor lesions, and therapeutic options in g-NENs.

PATIENT CONCERNS

The first patient was a 41-year-old female with weight loss, persistent dyspeptic complaints and a history of pernicious anemia. In the second clinical case a 61-year-old man was admitted with heartburn, abdominal pain, diarrhea and mild iron deficiency anemia. The third patient was a 56-year-old male with a history of neoplasia, admitted for weight loss, dyspeptic complaints, and liver metastases.

DIAGNOSIS

All the 3 patients underwent upper endoscopy with targeted biopsies. Histopathological and laboratory evaluation, together with imagistic evaluation (abdominal ultrasound, endoscopic ultrasound, and magnetic resonance imaging) allowed the distinction between 3 different types of gastric tumors: type 1 enterochromaffin-like-cell G1 NET, type 2 enterochromaffin-like-cell G2 NET, and type 3 G2 NET with liver metastases.

INTERVENTIONS

Endoscopic polypectomy of the largest lesion was performed in patient with type 1 g-NET and autoimmune chronic atrophic gastritis, followed by regular endoscopic surveillance with biopsies. In type 2 g-NET associated with pancreatic gastrinoma, pancreaticoduodenectomy with total gastrectomy were performed. In type 3 g-NET, detected in metastatic stage, oncologic therapy was performed.

OUTCOMES

The patients follow-up was selected according to tumor behavior, from regular endoscopic surveillance to oncology follow-up. The prognosis was good in case 1, whilst poorer outcomes were associated with more aggressive tumors in case 2 and case 3.

LESSONS

g-NENs are rare tumors with distinct clinical and histological features. Our case series emphasized the role of close collaboration between clinician and pathologist, as well as the importance of a detailed pathology report.

Association of Melanoma-Risk Variants with Primary Melanoma Tumor Prognostic Characteristics and Melanoma-Specific Survival in the GEM Study

Genome-wide association studies (GWAS) and candidate pathway studies have identified low-penetrant genetic variants associated with cutaneous melanoma. We investigated the association of melanoma-risk variants with primary melanoma tumor prognostic characteristics and melanoma-specific survival. The Genes, Environment, and Melanoma Study enrolled 3285 European origin participants with incident invasive primary melanoma. For each of 47 melanoma-risk single nucleotide polymorphisms (SNPs), we used linear and logistic regression modeling to estimate, respectively, the per allele mean changes in log of Breslow thickness and odds ratios for presence of ulceration, mitoses, and tumor-infiltrating lymphocytes (TILs). We also used Cox proportional hazards regression modeling to estimate the per allele hazard ratios for melanoma-specific survival. Passing the false discovery threshold (p = 0.0026) were associations of IRF4 rs12203592 and CCND1 rs1485993 with log of Breslow thickness, and association of TERT rs2242652 with presence of mitoses. IRF4 rs12203592 also had nominal associations (p < 0.05) with presence of mitoses and melanoma-specific survival, as well as a borderline association (p = 0.07) with ulceration. CCND1 rs1485993 also had a borderline association with presence of mitoses (p = 0.06). MX2 rs45430 had nominal associations with log of Breslow thickness, presence of mitoses, and melanoma-specific survival. Our study indicates that further research investigating the associations of these genetic variants with underlying biologic pathways related to tumor progression is warranted.

Pure and Mixed Desmoplastic Melanomas: A Retrospective Clinicopathologic Comparison of 33 Cases

BACKGROUND

Pure and mixed desmoplastic melanomas (DMs) may have different natural histories and behaviors.

METHODS

We conducted a retrospective review of patients diagnosed with DM at our institution between January 1997 and April 2019. A total of 33 unique DMs were identified and subsequently analyzed based on the histologic type (pure vs. mixed).

RESULTS

The majority (57.6%) of our cases were classified as pure histology. Patients with pure DMs were more likely to be men (P = 0.035) and be older than 65 years (P = 0.019) compared with patients with mixed DMs. Patients with mixed DM were more likely to have mitoses present (P = 0.001) compared with patients with pure DM. There were no differences in ulceration, perineural invasion, vascular invasion, or survival between patients with pure and mixed histologic subtypes. In addition, no differences in sentinel lymph node biopsy, radiation, or chemotherapy were noted between the 2 histologic subtypes. Immunohistochemistry showed that 27.3% of the pure DMs stained with Melan-A and HMB45 were positive for these immunomarkers.

CONCLUSIONS

Pure and mixed variants of DM were found to have similar clinicopathologic characteristics. Patients with the mixed histologic subtype were more likely to have mitoses, but no difference in the therapeutic management or patient survival was seen between the 2 subtypes.

The Relationship Between Epidermal Mitotic Density, Atypical Mitotic Figure Density, Breslow Depth, Ulceration, and Dermal Mitotic Rate in Cutaneous Melanoma: A Retrospective Cohort Study

Prognostic factors for melanoma include Breslow depth (BD), ulceration, and dermal mitotic rate (DMR). No studies have queried the effect of epidermal mitotic density (EMD) or atypical mitotic figure density (AMD) in an outcome-based assessment. Our objective was to determine if there is a relationship between EMD, AMD, BD, DMR, and ulceration and patient outcomes. This was a retrospective cohort study of 185 cases of thick and thin melanomas. Univariate and multivariate cause-specific regression analysis was performed. There was a positive correlation between EMD and BD (P = .0001). The difference between AMD in thick and thin melanomas was statistically significant. For every unit increase in EMD, patients had a 2.8-fold increase in the risk of distant metastasis; however, statistical significance was lost in the multivariate analysis. In adjusted analyses, ulceration, DMR, and BD were associated with outcomes. There were no statistically significant correlations between AMD and outcomes. This study is limited by its small sample size, diminution of the epidermis in some thick melanomas preventing EMD estimates, and reproducibility of mitotic figure counting. EMD and AMD do not seem to have any independent value in multivariate analyses for melanoma. Ulceration, BD, and DMR were significantly associated with outcomes and further solidify these known predictors of prognosis.

Speed rate (SR) as a new dynamic index of melanoma behavior

Melanomas are skin tumors that show a variety of biological behavior. Some develop very fast and some other grow extremely slow, with metastasis appearing, eventually, many years after the diagnosis. The number of mitoses in primary melanoma has been related to a more aggressive tumor and may have a potential as predictive factor for cutaneous melanoma survival. However, tumor mitotic rate is a static measure and in multivariate analysis on tumor survival, it has scored less than other tumor characteristics. We tried to evolve tumor mitotic rate from a static parameter to a time-dependent one. Similar to the already described growth rate (GR), we propose the speed rate (SR). SR is defined as the ratio of tumor mitotic rate to time to melanoma development. A prospective series of 345 patients with melanoma was investigated for the role of SR as predictive factor for sentinel lymph node (SLN) positivity and tumor progression. We calculated the best threshold for SR and GR to predict the risk of recurrence. Melanoma clinical and histological characteristics as well as GR were correlated in a multivariated analysis with SR. SR values >0.2 mitoses/month were associated with negative prognostic factors such as ulceration (82.8%), SLN positivity (80%), progression (82.8%), and death (85.7%). The association of GR > 0.3 mm/months and SR > 0.2 mitoses/month had a significant predictive value in terms of SLN positivity, progression, and recurrence-free survival. We propose SR as a new "dynamic" predictor of histological SLN positivity and melanoma recurrence risk. We think that he association with this new feature with GR may be helpful in improving the accuracy of predicted clinical outcome of patient especially with thin melanomas.

Bladder papillary urothelial neoplasm of low malignant potential in Chinese: a clinical and pathological analysis

Papillary urothelial neoplasm of low malignant potential (PUNLMP) had the incidence of low and definitive recurrence. Therefore, few studies showed that the relationship between pathological factors and the prognosis of patients with PUNLMP. The aim of this study assessed the linkage of pathological factors and prognosis of patients with PUNLMP including the presence or absence of mitoses and the thickness of urothelium. A retrospective analysis of 71 patients with PUNLMP was enrolled between January 2007 and June 2013. The clinicopathological factors consisting of tumor diameter, multifocality, the presence or absence of mitoses and cell thickness of urothelium were retrieved, Log-rank test and Cox proportional hazards regression models were used for univariate and multivariate analyses to evaluate the associations of these factors with recurrence-free survival (RFS) and progression-free survival (PFS).The incidence of recurrence and progression for PUNLMP was 19.7% and 16.9%, respectively. Patients with grade progression represented 85.7% in the recurrent patients. No patients had stage progression and no cases died from invasive urothelial carcinoma. Univariate analysis showed that the presence of mitoses, tumor diameter greater than or equal to 0.8 cm, multifocality were significantly correlated with worse RFS (P<0.05) and PFS (P<0.05). Multivariate analysis demonstrated that the presence of mitoses, tumor multifocality were significantly independent biomarkers for worse RFS (P<0.05) and PFS (P<0.05). Although the rare and infrequent mitoses were found for PUNLMP, the presence of mitoses and tumor multifocality were still the independent and poor predictors for the prognosis of PUNLMP. In addition, once the PUNLMP appeared to the recurrence, the inevitable grade progression could be determined, herein, long-term follow-up was necessary to be warranted, especially for patients with multiple lesions and the presence of mitoses.

Prognostic features in mucoepidermoid carcinoma of major salivary glands with emphasis on tumour histologic grading

AIMS

To compare the different grading systems of mucoepidermoid carcinoma (MEC) and identify the most reliable and objective histopathologic features predictive of outcome.

METHODS AND RESULTS

Seventy-two cases diagnosed as MEC were subjected to a meticulous histopathologic re-review. 20 of 72 (28%) cases were originally misdiagnosed as MEC including 16 as high grade (HG). Among the 52 confirmed MEC, median follow up (FU) was 59 months. Mitosis (≥4/10 High Power Fields), necrosis, pleomorphism, focal keratinization, desmoplasia, and lymph node metastasis were associated with adverse disease specific survival (DSS) and recurrence free survival (RFS) (P < 0.002). In all grading systems, low and intermediate grade had similar DSS and RFS but much better outcome than HG (P < 0.007). All patients with tumour harboring low mitotic rate and no necrosis did not recur except for one patient with a positive margin. All cases with high mitotic rate and necrosis died or recurred.

CONCLUSIONS

The majority of previously diagnosed HG MEC cases are misclassified. There is no difference in outcome between low and intermediate grade in all grading schemes. Consideration should be given to stratify MEC based on relatively objective criteria such as mitosis and necrosis.

Mitotic index, microvascular proliferation, and necrosis define 3 groups of 1p/19q codeleted anaplastic oligodendrogliomas associated with different genomic alterations

BACKGROUND

The aim of this study was to correlate histological features and molecular characteristics in anaplastic oligodendrogliomas (AOs).

METHODS

The histological characteristics of 203 AO patients, enrolled in the French national network POLA, were analyzed. The genomic profiles of 191 cases were studied using genomic arrays. IDH mutational status was assessed by immunohistochemistry and direct sequencing.

RESULTS

1p/19q codeletion was present in 79% of cases and was associated with alpha-internexin expression (P < 10(-4)), IDH1/2 mutation (P < 10(-4)), chromosome 4 loss (P < 10(-3)), and better overall survival (P < 10(-4)). Based on mitotic index, microvascular proliferation (MVP), and necrosis, 3 groups of 1p/19q codeleted AOs were identified: (group 1) AO with more than 5 mitoses per 10-HPF, no MVP, and no necrosis; (group 2) AO with MVP and no necrosis; and (group 3) AO with MVP and necrosis. Compared with group 1, groups 2 and 3 AOs had a higher mean Ki-67 proliferation index and a higher rate of 9p and 9q losses. Compared with group 2, group 3 AOs had a higher number of chromosomal alterations including chromosome 4 loss. In the subgroup of 157 1p/19q codeleted AOs, chromosomal instability was associated with shorter progression-free survival (P = .024) and shorter overall survival (P = .023).

CONCLUSIONS

The present study shows that oligodendrogliomas with classic histological features remain a molecularly heterogeneous entity and should be stratified according to 1p/19q status because of its major prognostic relevance. Moreover, 1p/19q codeleted AOs are also heterogeneous. Interestingly, mitotic index, MVP, and necrosis help to classify them into 3 groups associated with distinct genomic alterations.