David Kalfeřt

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.

LOW-GRADE MYOFIBROBLASTIC SARCOMA OF THE LARYNX: CASE REPORT AND REVIEW OF LITERATURE

Low-grade myofibroblastic sarcoma (LGMS) is a very rare, atypical myofibroblastic tumor with fibromatosis-like features with predilection mostly in head and neck region. LGMS occurs primarily in adult patients with a slight male predominance. Only few cases of LGMS affecting the larynx have been reported in literature to this date. We describe a case of low-grade myofibroblastic sarcoma of the larynx in a 40-year-old male patient. The clinicopathological characteristics, immunohistochemical findings and treatment are discussed.

Computerised static posturography in neurology

Posturography is a general term for techniques used to measure postural stability on static or dynamic measuring platforms. The principle of static computerised posturography (SCPG) is the detection of the centre of foot pressure (CFP) in upright stance on a posturography platform. Our communication deals with the importance of SCPG in differential topodiagnosis of vestibular syndromes in neurology. The set of examinations and evaluations carried out was divided among a control group of healthy subjects (77), a group of subjects with peripheral vestibular disorder (159), and a group of subjects with a non-peripheral balance disorder (82). Results obtained through the measurements were evaluated using descriptive statistics procedures and basic numerical and graphic statistical characteristics of the given groups. Our observations demonstrate that posturography is a valuable auxiliary test for balance disorders, especially given the lack of more suitable tests. According to our results, SCPG can be used for a rough differential topodiagnosis of balance disorders in neurology.

Detection of Cervical Lymph Node Micrometastases in Patients with Squamous Cell Carcinoma of the Oral Cavity, Pharynx and Larynx.

BACKGROUND The goal of this prospective study was to determine the frequency of micrometastases in patients with squamous cell carcinoma (SCC) of the oral cavity, pharynx and larynx in whom elective neck dissection was indicated (cN0). PATIENTS AND METHODS A total of 12 patients (10 males and 2 females) were enrolled in the study. The age ranged 42-73 years (median 62 years). Elective neck dissection was performed in all patients (8 ipsilateral, 4 bilateral) and a total of 256 lymph nodes were removed and sent for microscopic examination. RESULTS The presence of tumor cells in cervical lymph nodes was found in 5/12 (42%) patients. Micrometastases of SCC were found in two patients and isolated tumor cells (ITC) in two other patients. In the remaining one patient with oropharyngeal SCC, a micrometastasis of papillary thyroid carcinoma (PTC) was detected. Positive lymph nodes were localized in level II in three patients with SCC of larynx, hypopharynx and tongue base, respectively, in level I in one patient with SCC of oral tongue and in level III in one patient with PTC. CONCLUSION Our results indicate that SCC of head and neck has a high potential for creating micrometastases which frequency is higher compared to clinically detected macrometastases. Therefore, elective neck dissection or radiotherapy of the neck should be considered in patients with high risk of occult metastases or micrometastases.

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.

Histological Changes of the Middle Ear Ossicles Harvested during Cholesteatoma Surgery

BACKGROUND In the cholesteatoma surgery ossicles can be replaced to reconstruct middle ear function. It is important that these ossicles are free of squamous epithelium, to prevent residual disease. This study focuses on the histological findings of the malleus and incus harvested during cholesteatoma surgery. MATERIALS AND METHODS Eighty middle ears ossicles were examined in vivo and histologically to consider the relationship of cholesteatoma to ossicles, grade of bone destruction and invasion of cholesteatoma to deeper layers of bone. RESULTS Serious ossicular destruction was observed more frequently in incus compared to malleus (p=0.0065). Difference of ossicles destruction between children and adults was not significant (p=0.3032). Deep invasion of cholesteatoma into the vascular spaces or inner core of the bone was not observed. CONCLUSIONS Autograft ossicles from cholesteatomatous ears should not necessarily be rejected for reconstruction of the ossicular chain. Regarding the histological finding, the authors suggest mechanical cleaning of the ossicle surface to eliminate residual disease.

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.