PD-L1 and PD-1 expression in thyroid follicular epithelial dysplasia: Hashimoto thyroiditis related atypia and potential papillary carcinoma precursor

Programmed cell death ligand (PD‐L1)/PD‐1 expression has been studied in a variety of cancers and blockage of PD‐L1/PD‐1 pathway is a cornerstone of immunotherapy. We studied PD‐L1/PD‐1 immunohistochemical expression in 47 thyroid gland specimens in groups of (1) Hashimoto thyroiditis (HT) only; (2) HT and follicular epithelial dysplasia (FED); and (3) HT, FED, and papillary thyroid carcinoma (PTC). PD‐1 positivity was found in immune cells, namely in lymphocytes, macrophages, and plasma cells with mean values for lymphocytes and macrophages 9% in HT group, 4% in FED group, and 4% in PTC group. PD‐L1 positivity was identified in both immune cells and in the normal epithelial cells. In the HT group, mean PD‐L1 staining on immune cells was 6%, in FED group 5%, and in PTC group 7%. The mean PD‐L1 staining on the epithelial cells in the inflammatory parenchyma was 11.7% in HT, 13.4% in FED, and 8.3% in PTC group. The mean PD‐L1 staining of FED foci was 47.2% in FED group and 33.6% in PTC group. The mean tumor proportion score (TPS) was 10.4%, and the mean combined positive score (CPS) was 15.5. At the moment, PTC is not a target of immunotherapy. However, understanding the complex issue of concurrent inflammation and autoimmunity can importantly influence the cancer treatment in future.

Non-Invasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features Is Not a Cytological Diagnosis, but It Influences Cytological Diagnosis Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

A low-risk thyroid tumour, non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was introduced in 2016. NIFTP criteria require a thorough histological examination to rule out capsular and lymphovascular invasion, which denies the possibility of preoperative cytological diagnosis. Nevertheless, since the adoption of the new entity, the cytology of NIFTP has been a subject of interest.

OBJECTIVES

The present systematic review and meta-analysis investigate the cytological diagnosis of NIFTP.

METHOD

An online PubMed literature search was conducted between March 1, 2020, and June 30, 2020, for all original articles considering the cytology of histologically proven NIFTP. The studies including data on fine needle aspiration specimens classified by The Bethesda System for Reporting Thyroid Cytology (TBSRTC) categories, risk of malignancy (ROMs) in the TBSRTC categories, and cytomorphological features of NIFTP were included in the meta-analysis. Non-English studies and case reports were excluded. The data were tabulated and statistical analysis was performed with Open Meta-Analyst program.

RESULTS

Fifty-eight studies with a total of 2,553 NIFTP cases were included in the study. The pooled prevalence of NIFTP cases was calculated among 25,892 surgically resected cases from 20 studies and the results show that NIFTP consisted 4.4% (95% confidence interval [CI]: 3.5-5.4%) of all cases. Most of the NIFTP cases (79.0%) belonged to the intermediate categories of TBSRTC. The pooled distribution of NIFTP cases in each TBSRTC category was 1.3% (95% CI: 0.8-1.7%) in non-diagnostic (ND), 8.9% (95% CI: 6.9-10.8%) in benign, 29.2% (95% CI: 25.0-33.4%) in atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS), 24.2% (95% CI: 19.6-28.9%) in follicular neoplasm (FN), 19.5% (95% CI: 16.1-22.9%) in suspicious for malignancy (SM), and 6.9% (95% CI: 5.2-8.7%) in malignant. Compared to pre-NIFTP era, the pooled risk differences of ROM were reduced by 2.4% in ND, 2.7% in benign, 8.2% in AUS/FLUS, 8.2% in FN, 7.3% in SM, and 1.1% in the malignant category. The cytomorphological features of NIFTP were similar to follicular variant of papillary thyroid carcinoma (FVPTC) but lesser to papillary thyroid carcinoma (PTC).

CONCLUSIONS

Based on our results, NIFTP remains a histological diagnosis. Although cytomorphological features cannot be used in differentiating NIFTP from FVPTC, they may guide in separating NIFTP from PTC. Features such as papillae, microfollicles, giant cells, psammoma bodies, and the amount of papillary-like nuclear features should be taken into account when suspicious of NIFTP. NIFTP should not have papillae or psammoma bodies, and giant cells were rarely observed.

Follicular Epithelial Dysplasia as Hashimoto Thyroiditis-Related Atypia: a Series of 91 Specimens

Follicular epithelial dysplasia (FED) is described as Hashimoto thyroiditis-related atypia and is thought to be a possible precancerous lesion. Dysplasia as an interface between normal state and carcinoma is described in a wide range of diseases and carcinogenesis chains. On the other hand, inflammation-related atypia and cancerogenesis is also widely studied. In this study, we retrospectively analyzed 91 specimens of thyroid gland surgical resections with FED during a 10-year-period at the university hospital pathology department. The study population consisted of 68 females and 15 males aged between 22 and 86 years. The preoperative cytology diagnoses had mainly been in the indeterminate categories with prevailing AUS/FLUS results in the FED-only group (p = 0.005) and suspicious for malignancy and malignant in the group with FED plus adjacent malignancy. The decision for surgery was malignancy related in 48.2% of the cases. The lesions were sized 0.1-3.5 mm and multifocal in 45.1% of the cases. Immunohistochemically, the atypical cells were cyclin D1-positive in 67.5%, galectin-3 in 72.7%, CK19 in 85.7%, and HBME-1 in 87.0% of cases. In conclusion, FED is suggested to be a pathogenetic link between inflammation-related atypia and papillary carcinoma and thus a premalignant precursor of papillary carcinoma in HT as 36.1% of the specimens contained also papillary carcinoma in the present study. Both histopathological nuclear features and the immunoprofile of FED are widely shared with that of papillary carcinoma.

The Role of Cell Blocks and Immunohistochemistry in Thyroid Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Bethesda Category

INTRODUCTION

Thyroid cytology is a widely accepted tool in the clinical triaging of nodular lesions. Cell blocks (CBs) can help in the diagnosis of atypical lesions, namely, thyroid Bethesda category of Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS).

METHODS

In a series of 224 AUS/FLUS thyroid samples with CB, we studied CB cellularity and feasibility of 3 immunohistochemical markers (cytokeratin 19 [CK19], HBME-1, and galectin-3) apart and in combination.

RESULTS

The CBs were non-diagnostic in 34 cases. Twenty-four CBs contained <10 cells, 45 CBs 10-50 cells, and 121 CBs >50 cells. Notably, more cellularity was found in CBs performed by plasma-thrombin and in-house techniques (p < 0.001). The diagnostic accuracy to detect malignancy was 65.1% for CK19, 72.1% for HBME-1, and 70.3% for galectin-3.

CONCLUSION

In conclusion, CB cellularity is essential for successful immunohistochemistry application and further diagnostic workup of AUS/FLUS cases.

IgG4-positive plasma cells in Hashimoto thyroiditis: IgG4-related disease or inflammation-related IgG4-positivity?

Despite the interest of researchers in IgG4-related disease (IgG4-RD), many questions still remain unanswered regarding the thyroid gland. We aimed to clarify the relationship between IgG4-positive plasma cells and the histopathological pattern in the Hashimoto thyroiditis (HT) in a Finnish series. HT specimens (n = 280) were retrieved from the Department of Pathology, Fimlab Laboratories. After re-evaluation, 82 (29%) cases (72 females and 10 males, 52 ± 17 years) with significant fibrosis were selected. CD38, IgG and IgG4 positivity in plasma cells was evaluated by immunohistochemistry. Adjusted IgG4-positive plasma cells per HPF > 20 and IgG4- to IgG-positive plasma cell ratio > 30% were adopted as threshold criteria and related to other morphological features. IgG4-positive HT group included 13 cases (15% from fibrotic HT, 4.6% from all HT, 50 ± 15 years, 11 females) with adjusted HPF count 30 ± 5 (23-40) IgG4-positive cells. IgG4-positivity significantly correlated with the presence of lobulation, oncocytic metaplasia and certain type of fibrosis, fibrosis spread outside the gland, lymphocytes/plasma cells epithelial penetration, the predominance of microfollicles and follicular atrophy in the present study. Despite the persisting uncertainty whether HT is IgG4-RD, HT with IgG4-positive plasma cells is histopathologically distinct entity with some geographic variability.

[Molecular Aspects of Thyroid Tumors with Emphasis on MicroRNA and Their Clinical Implications]

BACKGROUND

Central to neoplastic transformation and tumor progression is alteration of the signaling pathways that control cell proliferation and apoptosis. The key mechanisms for this neoplastic process are genetic changes (mutations of cancer-related genes) and recently identified epigenetic changes that involve DNA methylation, chromatin remodeling (which has a profound effect on the control of gene expression), and noncoding, regulatory RNA (notably, microRNA - miRNA). MiRNAs control expression of their target gene post-transcriptionally. These molecular factors have potential as diagnostic, prognostic, and predictive molecular markers. Epithelial tumors of the thyroid gland are a histogenetically, morphologically, and pathobiologically heterogeneous group of neoplasms and require new, molecular approaches in clinical practice.

AIM

This review aims to present contemporary scientific knowledge of this molecular (genetic and epigenetic) field of sporadic thyroid tumors of follicular cell origin and their potential clinical implications. The fundamental mutations (BRAFV600E, RET/PTC, RAS, and PAX8-PPARG) in selected tumor types are described comprehensively. Special attention is paid to miRNAs, including their biogenesis, function, and expression profiles in the most common thyroid tumors - follicular adenoma, follicular carcinoma, and papillary carcinoma.

CONCLUSION

Thyroid cancer medicine has recently entered a new, molecular era. Comprehensive knowledge of all molecular aspects may improve diagnostics and management of thyroid neoplasms through the introduction of novel, progressive treatment strategies for this cancer. Further research on signaling pathway-related targets, standardization of methods, and evaluation of results are required.Key words: thyroid tumors - cancerogenesis - genetics - epigenetics - microRNA The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 19. 10. 2016Accepted: 2. 11. 2016.

Pathobiology of MicroRNAs and Their Emerging Role in Thyroid Fine-Needle Aspiration

OBJECTIVE

MicroRNAs (miRs) are noncoding, single-stranded regulatory RNA molecules involved in the posttranscriptional regulation of gene expression. They control the development and maintenance of the diverse cellular processes including proliferation, differentiation, motility and apoptosis. Expression of miRs is tissue-specific and each alteration of the tissue miR profile is associated with a distinct disease status.

STUDY DESIGN

We reviewed the literature on the expression of miRs in thyroid tumors, focusing on methodology and diagnostic and prognostic output. Separately, we analyzed 11 studies on miR profiles in thyroid cytological material.

RESULTS

Numerous studies have evaluated the miR profiles of thyroid tumors in an attempt to find a possible diagnostic and prognostic role. Both downregulation and upregulation of numerous miRs was found, but differences between the surgical pathology specimens and corresponding fine-needle aspirates in the expression of the same miRs were also reported.

CONCLUSIONS

The results from surgically resected material cannot be extrapolated into preoperative use without validation. For diagnostic use, the strong overlap between follicular adenoma and follicular carcinoma miR profiles is challenging. In summary, miR-221 and miR-222 are consistently upregulated in different types of thyroid carcinomas and might be used as markers of malignancy.

Thyroid atypia of undetermined significance or follicular lesion of undetermined significance: an indispensable Bethesda 2010 diagnostic category or waste garbage?

OBJECTIVE

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was introduced in thyroid cytology in 2007 and is now generally accepted. BSRTC categories include a morphologic description and risk of malignancy as well as follow-up suggestions in each group. However, the category entitled 'atypia of undetermined significance or follicular lesion of undetermined significance' (AUS/FLUS) is problematic. This category is heterogeneous and has been overused so far.

STUDY DESIGN

Twenty-six studies were included in a meta-analysis. In addition to AUS/FLUS percentage, we analysed repeated AUS/FLUS percentage, cytological and histological correlations, and risk of malignancy and neoplasm for AUS/FLUS. Furthermore, stratification, inter- and intra-observer variability, and the possibility of a switch to another category and its clinical consequences were reviewed.

RESULTS

Out of a total of 81,833 cases, AUS/FLUS accounted for 10.9%, with a 34% risk of malignancy. Persistent AUS/FLUS was found in 21.6% in repeated cytology. Cytohistological correlation was analysed from 16 studies (4,964 cases), revealing 10.4% as AUS/FLUS and a 21.5% risk of malignancy.

CONCLUSIONS

An AUS/FLUS category seems to be currently reasonable with clearly defined cytomorphological criteria which do not correspond unequivocally with those of the other categories. An AUS/FLUS category is justified and possible means of its improvement with immunohistochemistry, molecular analysis and imaging are discussed.

[Up-to-date experience with the international classification system Bethesda 2010 for thyroid fine-needle aspirate: a review]

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was introduced in thyroid fine needle aspiration cytology (FNAC) in 2010. A six-tier system is generally accepted. Bethesda categories include morphologic description, risk of malignancy and follow-up suggestions in each group. The system has its advantages and disadvantages, that are discussed. The most problematic are the categories of "Atypia of undetermined significance" or "Follicular lesion of undetermined significance" (AUS/FLUS). The group is heterogenous and overused thus far. The possibilities of its improvement are discussed. The Bethesda system does not include any prognostic and predictive markers. However, they represent the promising direction in the improved version of the BSRTC. Novel molecular methods and alternative techniques such as core needle biopsy are briefly discussed.

Oncocytic Schneiderian papilloma of frontal sinus

Oncocytic Schneiderian papilloma (OSP) is one of the three morphologically distinct tumors that arise from Schneiderian membrane (the others include exophytic papilloma and inverted papilloma). OSP almost always occurs unilaterally in the paranasal sinuses, usually in the maxillary sinus, ethmoid cells or sphenoid sinus. We report a case of a 64-year-old woman with OSP arising from the left frontal sinus. In the report herein, we describe an OSP originating in the region of frontal sinus, which, to the best of our knowledge, represents the first documented example in English literature of OSP developing in this anatomical site.

[Vitamin D in relation to head and neck cancer]

Vitamin D was lately introduced as the important anti-cancer agent with therapeutic potential to be used in prevention and therapy of malignant tumors. Head and neck squamous cell cancer (HNSCC) is the sixth most common cancer in the world. Prognosis of this cancer is in most patients poor. In attempts to improve therapy of this cancer, contemporary research is focused on extension of the etiological and pathobiological aspects of cancerogenesis of HNSCC. This fact provoked us to summarize present scientific knowledge about etiopathological, chemopreventive and therapeutic role of vitamin D in head and neck squamous cancer and outline the direction of further research in this interesting and from clinical point of view important field. Key words: head and neck squamous cell carcinoma - anti-tumor effect - vitamin D.

[New aspects of tumor pathobiology]

Several biological principles such as epigenetic changes, RNA interference, epithelial-mesenchymal transition, and cancer stem cell formation have been recently connected to the pathobiology of tumors. All these phenomena have, along with genetic changes, a significant impact on the neoplastic transformation and/or tumor progression. Authors report a review of the above mentioned "nongenetic" processes and their effect on the neoplastic transformation, and the appearance, behavior, prognosis, and therapy of tumors. Future diagnostic and therapeutic perspectives are also discussed.

[Influence AquaLase at corneal endothelial cells]

PURPOSE

To assess the effect of the cleaning of the posterior capsule using pulses of balanced salt solution (BSS) on the corneal endothelial cells.

METHODS

This pilot study involves 43 patients with bilateral cataracts having lens removal using torsional phacoemulsification (Ozil, Infiniti, Alcon) and bimanul irrigation/aspiration (I/A). Posterior capsule of the right eye of each patient was cleaned using pulses of BSS (AquaLase, Infiniti, Alcon). Surgery was performed by one of 2 surgeons (NJ, PR), both eyes of each patient was operated on by the same surgeon. Best corrected visual acuity (BCVA), endotelial cell count and pachymetry were evaluated pre- and postoperatively as well as occurence af peri- and postoperative complications.

RESULTS

Preoperative mean pachymetry (P) was 566 +/- 45 microm in the right eye (RE) and 562 +/- 42 microm in the left eye (LE), mean endotelial cell count (ECC) 2541 +/- 317 cells/mm2 (RE) and 2567 +/- 311 cells/mm2 (LE). Three months after surgery P was 557 +/- 43 microm (RE) and 558 +/- 45 microm (LE) and ECC 2368 +/- 416 cells/mm2 (RE) and 2396 +/- 417 cells/mm2 (LE). There was no statistical difference in postoperative changes of both corneal parameters between right and left eyes. Best corrected visual acuity improved in all eyes and no peri-or postoperative complications occured.

CONCLUSIONS

Cleaning of the posterior capsule using AquaLase is safe for corneal endothelial cells.

[Microbiological examination of the aqueous humor after implantation of the intraocular lens CORNEAL]

PURPOSE

To compare the results of the microbiological examination of aqueous humor after implantation of the intraocular lens (IOL) CORNEAL using either injector or forceps.

MATERIALS AND METHODS

In this prospective randomized clinical study 46 eyes (43 patients) were implanted with the hydrophylic acrylic IOL CORNEAL ACR6D SE. Injector was used in 23 eyes and folding and implantation forceps in 23 eyes. After delivery of the IOL in the capsular bag, viscoelastic material was removed using bimanual I/A and the specimen for microbiological examination was obtained. The anterior chamber was filled with balanced salt solution, intracameral antibiotics were injected and the stroma alongside the primary incision and the side port incisions were lightly irrigated to form a fairly secure seal.

RESULTS

The results of primary cultivation were negative in all specimen. Only threetimes sporadic colonies of Staphylococcus plasmacoag. neg. were isolated from the liquid medium after reincubation, that were described by microbiologist as very probably contamination of the sample. At two from these three cases forceps were used for implantation, once injector. Anaerobic and mycologic examinations of all samples were negative. There was no evidence of postoperative inflammation in any case.

CONCLUSION

Both implantation techniques proved to be safe with no significant differences comparing the microbiological examination and postoperative outcome.

[Prediction of treatment outcome after adjuvant loco-regional chemotherapy following liver resection for colorectal metastases--preliminary results]

INTRODUCTION AND AIM OF STUDY

Czech Republic leads the worldwide league in colorectal cancer's occurrence. Colorectal liver metastases are detected in about a half of patients with colorectal cancer. Liver resection of colorectal metastases is currently the only potentially curative treatment with a chance for a long-term survival rate. Until now there has remained a question of whether adjuvant HAIC can improve the treatment results of radical resection. The aim of our study is to verify predictive efficiency of thymidylátsyntasis (TS), dihydropyrimidindehydrogenasis (DPD) and thymidinfosforylasis (TP) in patients undergoing adjuvant hepatic artery infusion chemotherapy (HAIC) following radical liver resection for colorectal metastases.

METHODS

From 1990 to 2005 80 patients underwent 84 liver resections for colorectal metastases. R0 resection was achieved in 60 events. Ten patients who underwent R0 resection both for primary cancer and for colorectal liver metastases and who were given portcatheter for HAIC were included in this study. Adjuvant chemotherapy contained 5-fluorourycil (1200 mg/m2) combined with oxyliplatinum and leukovorin. Whole dose was administered via hepatic artery. The samples were procured both from healthy liver tissue and from metastases for imunohistochemical and molecular biological analysis.

RESULTS

The recurrence of disease was verified in 2 of 10 included patients (20%). We detected neither occurrence of death nor serious complication in early postoperative course in none of ten patients. Low expression of TS was found in both events and very high expression of DPD in one event was detected.

DISCUSSION

High expression of DPD in one of these patients could contribute to lower outcome of adjuvant chemotherapy. Low expression of TS in both patients responds to the written statement regarding contribution of adjuvant chemotherapy only in patients with high TS level.

CONCLUSION

The expression of TS and DPD responds to expected outcome of HAIC. Low number of patient does not permit statistic evaluation.

Massive squamous metaplasia of the thyroid gland – Report of three cases

Three cases of massive squamous cell metaplasia in Hashimoto's thyroiditis are reported. The patients were two men and one woman aged 24, 52, and 55 years, respectively. In all three patients, the glandular parenchyma was replaced by hypocellular fibrous tissue with scattered chronic inflammatory infiltrate. Follicular cells were almost absent; the majority of residual epithelial cells formed squamous nests that were partly solid and partly cystic. There were three types of epithelial cells - squamous, basaloid, and follicular, with oncocytic differentiation. The squamous and basaloid cells showed strong positivity high molecular weight (HMW) cytokeratin, moderate to strong expression of galectin-3 (2/3), and nuclear expression of p63 protein (2/3). The staining pattern of p63 was identical to that of HMW, with predominant positivity at the periphery of cell nests. In one case, weak but unequivocal positivity of thyroid transcription factor-1 also was present. We believe that metaplasia was caused by Hashimoto's thyroiditis. The cases presented here are extremely rare, and only two convincing similar cases have been reported in the English literature so far. They may represent a diagnostic pitfall and should not be misdiagnosed as a malignancy, in particular as squamous cell or mucoepidermoid carcinoma.

Proliferative markers in diagnosis of thyroid tumors: a comparative study of MIB-1 and topoisomerase II-a immunostaining

BACKGROUND

The differential diagnosis of well-differentiated tumors of follicular cell origin remains a most problematic task in thyroid pathology. Therefore, various diagnostic/prognostic thyroid markers are currently being studied. The aim of our study was to evaluate the proliferative MIB-1 and topoisomerase II-alpha markers in both oncocytic and non-oncocytic epithelial thyroid tumors.

MATERIALS AND METHODS

Proliferative activity was analyzed by means of immunohistochemistry in 215 thyroid tumors and the evaluated proliferative indices (PI) were correlated with morphological diagnosis. Comparison of both proliferative markers was made. The results were statistically analyzed using Wilcoxon tests (significance level p<0.05) and the Spearman correlation coefficient.

RESULTS

Carcinomas generally showed significantly higher PI than adenomas, irrespective of their oncocytic or non-oncocytic features. Moreover, PI in oncocytic adenomas was significantly higher than in non-oncocytic ones. However, PI in both oncocytic and non-oncocytic carcinomas, including papillary microcarcinomas, were similar. The studied proliferative markers correlated with each other.

CONCLUSION

PI can help the differential diagnosis of morphologically difficult cases of thyroid tumors. Oncocytic adenomas have higher malignant potential and should be promptly surgically removed. Both MIB-1 and topoisomerase II-alpha are recommended for the evaluation of thyroid tumor cell proliferation.

Epithelioid haemangiosarcoma of the thyroid gland. Report of six cases from a non-Alpine region

AIM

To report a series of six cases of thyroid haemangiosarcoma (HAS) from a non-Alpine region.

METHODS AND RESULTS

The patients were four females and two males, aged 54-81 years (average 68 years). The tumours presented as large haemorrhagic masses (diameter 40-70 mm, average 56 mm) with extensive necrosis. Histologically, they were composed of polymorphous epithelioid cells with vesicular nuclei and abundant eosinophilic cytoplasm with occasional intracytoplasmic lumina. Mitotic activity was high. Tumor cells expressed vimentin (6/6), CD31 (6/6), FVIII (5/6), CD34 (2/6), and cytokeratins (5/6). One tumour (1/6) over-expressed p53 protein in more than 20% of cells. Ultrastructurally, Weibel-Palade bodies were present (4/6). Clinical follow-up of four patients (range 3-24 months, median 9 months) showed that two of them have died of the disease 0.5 and 3 months after diagnosis, one died of unrelated causes (with 24 months' uneventful follow-up) and one is alive 21 months after operation with no evidence of disease.

CONCLUSIONS

Although thyroid HAS is usually regarded as an extremely aggressive neoplasm with a dismal prognosis similar to anaplastic carcinoma, one of our cases suggests that HAS can behave in a less aggressive way. The morphological, immunohistochemical and ultrastructural findings support the hypothesis that thyroid HAS is a distinct entity, unrelated to other thyroid malignancies.

[Thyroid peroxidase in the differential diagnosis of thyroid gland lesions. A marker of biological behavior or differentiation?]

Human thyroid peroxidase (hTPO) is a membrane protein with a key role in the thyroid hormones synthesis. Loss of hTPO was described in malignant tumours of the thyroid gland. hTPO was tested as a marker of malignancy. Immunohistochemical study of hTPO in 321 thyroid lesions (45 malignant tumours, 72 benign tumours, 199 benign non-tumours lesions, and 5 normal thyroid glands) is presented. The sensitivity of hTPO in predicting malignancy in thyroid is 64%, and the specificity is 87%. Thus, hTPO is of limited value in the diagnosis of thyroid malignancy. The authors discuss the role of hTPO as a marker of differentiation.

Immunohistochemical detection of dipeptidyl peptidase IV (CD 26) in thyroid neoplasia using biotinylated tyramine amplification

Differential diagnosis between malignant and benign thyroid tumors derived from follicular cells can pose certain difficulties in routine surgical pathology. The aim of the study was to evaluate dipeptidyl peptidase IV (DPP IV/CD 26) in differential diagnostics of thyroid lesions. DPP IV/CD 26 was evaluated in thyroid glands of 309 patients (261 females and 48 males, age range of patients 15-80 years). DPP IV/CD 26 was assessed in paraffin-embedded thyroid specimens immunohistochemically using commercially available antibody (Serotec) and biotinylated tyramine amplification kit (DAKO). Well-differentiated carcinoma revealed DPP IV/CD 26 positivity in 33 out of 42 cases (79%). Neither medullary nor insular carcinoma was DPPIV/CD 26 positive (only one case of each tested). DPPIV/CD 26 expression in isolated cells was seen in 18/261 (7%) benign disorders. The sensitivity of the method was 68%, the specificity was 94%, and the diagnostic accuracy was 91%, respectively, using 5% threshold of positive follicular cells. DPP IV/CD 26 can be assessed immunohistochemically using biotinylated tyramine amplification kit. DPP IV/CD 26 could be an adjunct in the thyroid gland differential diagnosis. However, DPP IV/CD 26 positivity is limited to the group of well-differentiated carcinomas, particularly papillary carcinoma. Furthermore, it is of limited value for follicular and oncocytic tumors.

Molecular diagnosis of Epstein-Barr virus in paraffin-embedded tissues of tumors with abundant lymphoid infiltration

To evaluate the significance of Epstein-Barr virus (EBV) infection in tumorogenesis, we examined ten archival samples of acinic cell carcinomas of salivary glands with lymphoid-rich stroma, four archival samples of lymphoepithelioma-like carcinomas (LELC) of the urinary bladder, ten samples of oncocytic papillary carcinoma of the thyroid (Warthin-like tumors) and one sample of lymphoepithelioma-like carcinoma of the cervix, together 25 paraffin-embedded tumor tissues. Polymerase chain reaction (PCR) and in situ hybridization (ISH) assays were used. The EBV genome was detected by PCR using primers targeting the IR region. ISH was performed using EBER oligonucleotide probes. Each examination was repeated two times. Positive PCR result was obtained in 12% of samples only. However, this result was not confirmed by the subsequent second PCR examination. ISH revealed negative signals in all samples. Our results demonstrate the importance of the diagnostic strategy based on combination at least two independent methods. PCR due to its sensitivity may produce false positive results depending on the degree of infiltration the tumor sample by EBV carrying lymphocytes.

Focal sarcoid-like change of the thyroid gland. A possible consequence of aspiration cytology?

An unusual case of focal accumulation of sarcoid-like granulomas occurring within the thyroid gland of a 43-year-old female patient is reported. The granulomas were found solely at the site of previous fine needle aspiration biopsy. The follow-up did not show any symptoms of systemic granulomatous disease. The pathogenesis of this lesion is discussed.

[Dipeptidyl peptidase IV (DPP IV, CD 26): a tumor marker in cytologic and histopathologic diagnosis of lesions of the thyroid gland]

BACKGROUND

Morphological diagnostics of thyroid gland tumours faces certain differential diagnostic problems. Extensive histological examination of the entire tumour is required for the final diagnosis of follicular and oncocytic tumours. Thus, assessment of reliable definitive cytological and/or intraoperative histological diagnosis is not possible. No marker of malignancy has been so far generally accepted in the thyroid tumour diagnosis. The aim of the study was to evaluate membrane protease dipeptidyl peptidase IV (DPP IV) in the differential diagnosis of thyroid tumours.

METHODS AND RESULTS

DPP IV was assessed cytochemically in 254 smears, histochemically in 314 cryostat sections, and immunohistochemically in 309 paraffin-embedded sections obtained from the group of 336 patients. There were 283 females and 53 males with the mean age of 48 years (range 15-80 years) in this series. Sensitivity of cytochemical detection was 71%, specificity was 96%, and diagnostic accuracy was 93% using the 50% threshold. Histochemically, sensitivity was 71%, specificity was 93%, and diagnostic accuracy was 90% using the 5% threshold. Using the immunohistochemical assessment, sensitivity was 68%, specificity was 94%, and diagnostic accuracy was 91% using the 5% threshold.

CONCLUSIONS

According to our results, DPP IV can be used as a marker of malignancy in well-differentiated carcinomas of follicular cell origin, namely in papillary carcinoma. However, it is less reliable in follicular and oncocytic carcinomas.

Dipeptidyl peptidase IV expression in thyroid cytology: retrospective histologically confirmed study

Fine needle aspiration cytology (FNAC) of the thyroid gland is a well-established method. However, it has inherent limitations, especially in the diagnosis of follicular and oncocytic tumours and in distinguishing between nuclear atypia in colloid goitre with regressive changes and cystic papillary carcinoma. The aim of our study was to evaluate dipeptidyl peptidase IV (DPP IV) as a marker of malignancy in FNAC. We tested 254 thyroid specimens (intraoperative imprint smears) for DPP IV. The sensitivity was 71%, the specificity was 96%, and the diagnostic accuracy was 93%, respectively, with a threshold of 50% of positive cells. To the best of our knowledge it is the largest histologically confirmed study reported in the literature. We suggest the assessment of DPP IV as an adjunct diagnostic marker of malignancy in thyroid specimens suspicious of papillary carcinoma. However, the value of the marker in follicular lesions is very limited.

[Secondary changes in the thyroid gland induced by aspiration cytology]

Due to the introduction of fine needle aspiration cytology (FNAC) to the routine clinical preoperative examination surgical pathologists are faced with thyroid gland specimens with FNAC-induced secondary changes. These changes can cause diagnostic difficulties and be a source of incorrect diagnosis. Authors present a review of FNAC-induced changes with differential diagnostic criteria helpful in these pitfalls. FNAC-induced changes can be schematically divided into two major groups--recent ones (intranodal bleeding and/or necrosis) and subacute/late ones (proliferation of granulation tissue with predominance of myofibroblasts or endothelial cells, resorptive pseudoxantomathous granulomas, formation of sarcoid-like granulomas, capsular pseudoinvasion and scarring). Pathologists should be informed about the previously performed FNAC and must be aware of these lesions to prevent their misinterpretation.

[Dipeptidyl(amino)peptidase IV in the differential diagnosis of thyroid gland tumors: methods and results of a pilot study of 200 cases]

The use of dipeptidyl aminopeptidase IV (DPP IV) staining by azo-coupling in preoperative and intraoperative diagnostics of thyroid lesions is presented. In a series of 200 histologically confirmed cases examined, the sensitivity and the specificity were 71% and 99%, respectively in 124 smears, and 70% and 94%, respectively in 189 frozen sections. DPP IV expression showed high negative predictive value as well. DPP IV is suggested as an additional tool in the preoperative and intraoperative diagnostics of thyroid lesions.

[Role of the MIB-1 proliferative markers in the diagnosis and prognosis of tumors of the thyroid gland]

Well-differentiated thyroid tumors may sometimes cause diagnostic uncertainty due to difficulties in the evaluation of certain morphological criteria (capsular and/or vascular invasion, cytomorphological features). Therefore, various diagnostic/prognostic markers are currently studied, namely the markers of tumor proliferation. The aim of our study was to evaluate the proliferative MIB-1 index in 155 thyroid tumors, and to correlate it with morphological diagnosis, size of the tumors, and the patients' age. Oncocytic tumors were represented by 59 follicular adenomas, 27 follicular carcinomas and 12 papillocarcinomas. Nononcocytic tumors comprised 24 follicular adenomas and 33 conventional papillary carcinomas. The Ki-67 antigen (formalin resistant epitope MIB-1) was detected immunohistochemically and the proliferative index (PI) of tumors was evaluated. The results were statistically analyzed using analysis of variance (ANOVA) and Wilcoxon tests (significance level p < 0.05). Carcinomas showed significantly higher PI than adenomas. Moreover, PI in oncocytic adenomas was higher than in nononcocytic ones. However, proliferative activity in all types of the carcinomas was similar. The higher rates of proliferation correlated with the advanced age of the patients with follicular carcinomas (p < 0.0016).

Oncocytic papillary carcinoma with lymphoid stroma (Warthin-like tumour) of the thyroid: a distinct entity with favourable prognosis

AIMS

We report the clinicopathological and immunohistochemical characteristics of 12 cases of a recently recognized entity, oncocytic papillary thyroid carcinoma (PC) with lymphoid stroma (Warthin-like tumour).

METHODS AND RESULTS

The cases were retrieved from the surgical pathology files of our departments. There were 11 female patients and one male patient; they ranged in age from 45 to 85 years (mean 64.2 years). The immunohistochemical profile demonstrated positivity of tumour cells for cytokeratins, thyroglobulin, Leu-M1 and anti-mitochondrial antigen. S100 protein-positive stromal dendritic/Langerhans cells were uniformly present. Polymerase chain reaction, in situ hybridization, and immunohistochemistry for Epstein-Barr virus (EBV) detection revealed no significant positive signal. MIB-1 labelling index was low, compatible with that of 'classical' PC.

CONCLUSIONS

Warthin-like tumour is a rare variant of PC, occurring predominantly in elderly women. Its histological features are distinct and well recognizable, differentiating this tumour from a more aggressive tall-cell variant of PC. The apparent indolent behaviour seems to be consistent with the presence of dendritic/Langerhans cells and with low proliferative activity. A possible role of EBV in pathogenesis of this lesion was not proven. Further studies are necessary to determine the prognosis and metastatic potential of this neoplasm.

[Stromal tumor of the small intestine--a cause of massive gastrointestinal hemorrhage]

A 41-year-old man attended our clinic with massive gastrointestinal bleeding due to a tumor of the small intestine. The tumor was not diagnosed until during acute laparotomy. The histological examination revealed a gastrointestinal stromal tumor with uncertain biological behaviour. The authors discuss the rare gastrointestinal stromal tumors, where preoperative diagnosis is difficult and in symptomatic forms urgent laparotomy is usually the only diagnostic method. The differential diagnosis between leiomyoma, schwannoma, mesenterial fibromatosis or intraabdominal solitary fibrous tumor as well as metastatic melanoma is not simple and immunohistochemistry plays a leading role. Prediction of biological behaviour of these tumors is also problematic and depends on the histological picture, site, size and mitotic activity.

[Angiogenesis in tumors. Part II. Methods and significance of quantification; angiogenesis as a prognostic indicator and the target of therapeutic approaches]

The efforts to quantify tumor angiogenesis (AG) have been limited by the methods available. Only since introduction of immunohistochemistry, detection of early stages of capillary vessel formation is enabled. There were reports showing strong correlation between AG and behavior of the tumor (namely formation of metastases, disease free interval, and overall survival) particularly in carcinomas of the breast, prostate, esophagus, stomach and colon. However, significance of these studies is strongly dependent on the methodological aspects, e.g. the choice of visualized endothelial antigen, microscopic magnification and selection of areas with highest angiogenic activity (so called "hot spots"). We present a review of studies focused on AG and discuss pitfalls, which could bias the results. Current clinical applications as well as perspectives of future antiangiogenic treatment are also discussed.

Hyalinizing spindle cell tumors with giant rosette-like structures

We report two cases of hyalinizing spindle cell tumors with giant rosettes arising in the pararectal space and soft tissues of the wrist in a 46-year-old man and 22-year-old-woman, respectively. Microscopically, the tumors exhibited a varied morphology, including hyalinizing hypocellular and cellular fibromatosis-like areas. The most striking morphologic feature was the formation of giant rosette like structures with collagen cores scattered throughout the tumors. Most of the tumor spindle cells were diffusely immunoreactive for lysozyme, CD-68, factor XIII and vimentin. Reactivity for smooth muscle actin, desmin and S-100 protein was not found. Ultrastructural examination of the rosettes in one case only showed normal native collagen.

Gastric lipoma presenting as upper gastrointestinal obstruction

A 61-year-old man presented with an upper gastrointestinal obstruction caused by a submucosal gastric lipoma in the prepyloric area. The diagnosis was made coincidentally during his admission for another disease. Gastric resection was performed because of a large lipoma combined with florid gastric ulcers. The frequency of gastric lipoma, its differential diagnosis, means of diagnosis, and treatment are discussed.

Nodular mucinosis of the breast: report of three cases

Three cases of nodular mucinosis of the breast are presented. They occurred in one male and two female patients. The patients had no signs of Carney's syndrome. All lesions were located under the nipple. They were poorly circumscribed and unencapsulated. They were soft and had a gelatinous consistency and white color. No patient had any evidence of recurrence or metastasis 6 months, 3 years and 6 years, respectively, after the surgical excision. The mucinous tissue consisted of acid mucopolysaccharides, which stained Alcian blue, Hale's colloidal iron positively, and they were periodic acid-Schiff (PAS) negative. Mucicarmine reaction was only faintly positive. The lesion should be distinguished particularly from mucocele-like lesions of the breast by the location, nodular arrangement, absence of accompanying ductal hyperplasia and staining properties of the mucous substances.

Pigmented microcystic chromophobe cell carcinoma: a unique variant of renal cell carcinoma

Five cases of pigmented chromophobe renal cell carcinoma are presented. The patients included four men and one woman between the ages of 60 and 73 years (median age, 66.5 years), who presented with symptoms due to their renal mass. Surgical resection of the renal mass was performed in all patients. Grossly, the tumors were well encapsulated, yellow to dark gray, with a vague nodular pattern on cut surface. The tumors varied between 2.5 and 9 cm in greatest diameter. Histologically, all tumors shared similar features, namely, a malignant cellular proliferation composed of deeply eosinophilic to clear cytoplasm with round nuclei and inconspicuous nucleoli. The cellular proliferation was arranged in a microcystic and/or microalveolar pattern. In one tumor, conventional areas of clear cell carcinoma in association with the chromophobe component were present. In addition, all tumors contained pigmented areas, which were shown by light microscopy to have features of lipochrome pigment. Ultrastructural studies of these areas demonstrated the presence of intracytoplasmic polygonal to round, electron-dense pigment granules, which in some areas seemed to coalesce to form larger granules. In addition, numerous mitochondria and cytoplasmic vesicles were present. The cases described herein highlight an additional morphologic variant of chromophobe renal cell carcinoma.

Intrathyroidal lymphoepithelial cyst. A report of two cases not associated with Hashimoto's thyroiditis

Two cases of intrathyroidal lymphoepithelial cyst are described. Both of them were solitary, one being found incidentally in a patient operated on for a multinodular goiter, the other being clinically obvious as a cold nodule. They exhibited features of cysts of branchial cleft origin, i.e. squamous cell lining epithelium and abundant lymphoid tissue with reactive germinal centers. The thyroid gland parenchyma showed a discrete lymphoid infiltration consistent with the diagnosis of focal lymphocytic thyroiditis. In the first case a single epidermoid solid cell nest was found. The histogenesis of intrathyroidal lymphoepithelial cysts remains unclear, but their origin from cystically degenerated ultimobranchial body remnants (solid cell nests) seems to be most probable. This assumption is supported by a similar immunohistochemical profile of solid cell nests and epithelial cells lining the cysts and also by the presence of one solid cell nest in the proximity to the cyst in one of our cases.

[Psammomatous melanotic schwannoma]

Psammomatous melanotic schwannoma is a rare variant of schwannoma. The authors present histological and immunohistochemical findings in two cases of the tumor arising in the spinal nerve roots region at a 56-year-old woman and a 58-year-old man. The latter recurred locally. Microscopically the tumor was composed of polygonal epithelioid or spindle-shaped cells. Some of these cells contained melanin. Small calcifications were dispersed throughout the lesion. Ultrastructural examination of one of these cases revealed nerve sheath origin of the tumor cells and identified premelanosomes and melanosomes within the cytoplasm of neoplastic cells. Histogenesis and relationship of the tumor to Carney complex are discussed.

[Multiple lymphomatous polyposis of the gastrointestinal tract]

We studied three patients in whom histology revealed multiple lymphomatous polyposis of the gastrointestinal tract. It is a distinctive type of primary gastrointestinal lymphoma characterized by polypoid accumulations of lymphoma tissue involving long segments of the gastrointestinal tract. This lymphoma consists of a diffuse proliferation of small round lymphocytes and small cleaved cells and tends to an extraintestinal dissemination. Clinical behavior of this entity is more aggressive than that of the same primary nodal lymphoma. We discuss the evolution of opinions of this entity.

[Myofibroblastic proliferative lesions in the paratesticular area]

Myofibroblastic pseudotumorous proliferations have been recognized at a variety of sites. Six cases of paratesticular myofibroblastic lesions with emphasis on the spectrum of morphologic features were described. The microscopic features changed from abundant cellular spindle cell proliferation resembling nodular (pseudosarcomatous) fasciitis to hypocellular and hyalin fibrovascular lesion with extensive dystrophic calcification. The age of the patients ranged from 14 to 77 years. In four cases sarcoma was suspected histologically. Differential diagnosis and histogenesis of the lesion were discussed.

[Segmental mediolytic arteriopathy]

Three cases of segmental mediolytic arteriopathy occurring in abdominal muscular arteries are presented. This unusual arterial lesion is noted for cytoplasmic vacuolar degeneration of the arterial smooth muscle cells, intercellular vacuoles of various sizes, and focal arterial wall defects designated "arterial gaps". This spectrum of histologic changes can progress to formation of aneurysms with rupture of the vascular wall. The extensive intraabdominal haemorrhage led to the death of all our patients. Pathogenesis and differential diagnosis of this lesion is discussed.

Mixed medullary-follicular and medullary-papillary carcinoma of the thyroid: one or two entities?

Among 36 cases of medullary carcinoma of the thyroid we found two cases of mixed medullary-follicular carcinoma which in addition to the typical morphology contained foci of clear cells with cytological features of papillary carcinoma of the thyroid. The authors compare the two cases with the recently described entity called medullary-papillary carcinoma of thyroid.