Cytopathology and diagnostics of Warthin's tumour.

Warthin's tumour (WT) is a benign epithelial salivary tumour, one type of salivary adenoma. Histologically, WT is structured of two components, epithelial tissue that often lines cystic formations and lymphoid tissue in the tumour stroma. FNA is a reliable diagnostic approach in the diagnosis of salivary gland lesions allowing a highly accurate categorization of benign tumour-like lesions, benign tumours and malignant tumours. In the proposed Milan reporting system of salivary gland lesions, WT is categorized in the IVA group of benign neoplasms. Accurate cytological diagnosis is straightforward when three characteristic components are present: oncocytes, either isolated or associated in clusters, lymphocytes and lymphoid cells and often an inflammatory/necrotic-like substance. Also, specific features of scintigraphy and radiological imaging contribute to the diagnosis of WT. WT is categorized according to Seifert G. et al in 4 types, depending on the proportions of the epithelial component and lymphoid stroma. Differential cytopathological and pathohistological diagnosis include other salivary gland lesions with lymphoid, oncocytic epithelial and cystic components. In some cases, such as the metaplastic WT variant, there are additional cytopathological and histological diagnostic difficulties. Moreover, bilateral, multicentric or multiple and infrequently seen extra-salivary localizations of WT are associated with further cytopathological diagnostic difficulties. Also, a rare possibility of malignant transformation of the epithelial or lymphoid component of WT as well as possible association with other primary tumours remains a challenge in accurate cytopathological and histological diagnosis of WT.

Immunoexpression of 5-methylcytosine (5mc) in Bone Marrow Haematopoietic Cells in Patients with Myelodysplastic Syndromes.

Myelodysplastic syndromes (MDS) are biologically and clinically heterogenous groups of clonal haematopoietic stem cell diseases characterized by ineffective haematopoiesis and peripheral blood cytopenia, with a variable tendency to transform within acute leukaemia (AL). DNA hypermethylation and hypo-methylation are associated with cancer. Thus, the hypermethylation of DNA is essential for the molecular pathophysiology of MDS by inactivating genes involved in cell growth, differentiation and apoptosis. It was documented that the 5-methylcytosine (5mc) immunostaining score of BM haematopoietic mononuclear cells is higher in MDS patients than in a normal control group, and that the prognosis of the disease significantly correlated with global DNA methylation, age and IPSS score. In our study, we analysed the immunocytochemical expression of 5mc in bone marrow (BM) mononuclear cells from 13 MDS patients and a control group consisting of 13 patients with anaemia of chronic disease. The immunopositivity of 5mc BM mononuclear cells was statistically significantly higher in our MDS patients than in patients with anaemia of chronic disease. In most MDS patients (11 out of 13), a higher 5mc immunopositivity of BM mono-nuclear cells (above 10%) was found. Our results are in concordance with data from literature observing that a higher percentage of 5mc immunopositive BM mononuclear cells is documented in MDS patients.