Obesity and insulin resistance are closely associated with chronic inflammation in adipose tissue, where macrophages play an important role. Adipose tissue macrophages can be divided into two main phenotypes: the classical M1 macrophages and alternatively activated macrophages M2. M1 macrophages produce pro-inflammatory cytokines (TNF-α, interleukin IL-6 and MCP-1) and thus contribute to the development of insulin resistance. On the other hand, M2 macrophages, anti-inflammatory, are involved in the maintenance of tissue homeostasis and are typical in the adipose tissue of slender individuals. Macrophages can also play a role in the pathogenesis of other serious illnesses such as cardiovascular diseases or cancer. This article reviews the latest data on macrophage polarization in adipose tissue.

We report four cases of parotid gland tumours composed predominantly of spindle-shaped myoepithelial cells and mature adipocytes. The central portion of one tumour showed extensive adipose differentiation, whereas in the peripheral parts there were small foci of ductal epithelium arranged in cords and tubules within an abundant myxoid stroma. The other cases were adipose spindle cell myoepitheliomas without an obvious glandular component. Under high-power examination, a transition between modified spindle-shaped myoepithelial cells and adipocytes was observed, and this was confirmed with immunohistochemistry. Ultrastructurally, the modified myoepithelial cells showed intracytoplasmic tonofilaments, bundles of actin microfilaments and lipid droplets. A possible pathogenesis is proposed of true metaplastic transformation of myoepithelial cells to adipocytes. This lesion is important to identify correctly, as inadequate surgery can lead to recurrence.

EUS-FNA provides accurate diagnosis in 92% and has positive therapeutic impact in two-thirds of patients with solid pancreatic mass. Despite negative cytology, surgical exploration is recommended in clinical suspicion for pancreatic cancer and solid mass on EUS.

Background: Immunoglobulin G4 (IgG4)-related diseases are a group of diseases characterized by enlargement of the affected organs, elevation of serum IgG4, massive infiltration of affected organs with lymphocytes and plasma cells with IgG4 positivity and tissue fibrosis. Type I autoimmune pancreatitis is one form of IgG4-related disease. For IgG4-related diseases, various localizations are described for up to 10% of malignancies. The aim of our study was to examine IgG4 serum levels and pancreatic tissue with respect to the simultaneous presence of autoimmune pancreatitis in patients with pancreatic cancer. Methods: IgG4 serum levels were examined In 106 patients with histologically confirmed pancreatic cancer. The level of 135 mg/dl was considered as the normal value. Pancreatic tissue was histologically examined with respect to the presence of markers of autoimmune pancreatitis. Results: A higher IgG4 level than the cut-off value of 135 mg/dl was proven in 11 patients with pancreatic cancer. Of these 11 patients, 7 had levels twice the normal limit (65.6%). Autoimmune pancreatitis was diagnosed in these individuals. In the case of 1 patient, it was basically an unexpected finding; another patient was initially diagnosed with autoimmune pancreatitis. Repeated biopsy of the pancreas at the time of diagnosis did not confirm the presence of tumour structures, therefore steroid therapy was started. At a check-up 6 months after starting steroid therapy, the condition of the patient improved subjectively and IgG4 levels decreased. However, endosonographically, malignancy was suspected, which was subsequently confirmed histologically. This patient also demonstrated an IgG4 level twice the normal limit. Conclusion: IgG4-related diseases can be accompanied by the simultaneous occurrence of malignancies, which also applies to autoimmune pancreatitis. Chronic pancreatitis is considered a risk factor for pancreatic cancer. It cannot be reliably confirmed whether this also applies to autoimmune pancreatitis. In accordance with other works, however, it is evident that, despite the described high sensitivity and specificity for IgG4 elevation in the case of autoimmune pancreatitis, even levels twice the normal limit are demonstrable in some individuals with pancreatic cancer, without the presence of autoimmune pancreatitis. We believe that patients with IgG4-related disease, including autoimmune pancreatitis, must be systematically monitored with respect to the potential presence of malignancy.

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