Results of morphological screening for Lynch syndrome during the period 2013-2016.

The introduction of a screening system for Lynch syndrome in pathology laboratories in Plzen yielded 24 diagnoses of Lynch syndrome during the period of 2013-2016, 20 of them presenting with colorectal cancer. In 8 of those 24 cases germline mutations of MMR genes, previously not recognized as pathogenic with certainty, were detected. Although the frequency of Lynch syndrome in patients with colorectal cancer was only 0.34 % in total, following introduction of the universal immunohistochemical investigation of MMR (mismatch repair) proteins expression in all colorectal cancers examined in Sikl´s Institute of Pathology the frequency per year in this department reached 2.4 %. The results favor universal immunohistochemical screening for Lynch syndrome in colorectal and endometrial cancer cases over a selective approach based on a combination of clinical and morphological criteria. Increased effectiveness of the universal approach is not brought about only by higher sensitivity of the immunohistochemical examination per se, but also by the possibility of automation of the process leading to increased adherence even of pathologists not directly engaged in Lynch syndrome management. However, the introduction of a nation-wide universal screening system requires support from the government and health insurance companies. Keywords: colorectal cancer - endometrial cancer - immunohistochemistry - Lynch syndrome - MMR - screening.

The expression of PD-L1 in patients with castrate prostate cancer treated with enzalutamide.

PURPOSE: The purpose of our retrospectively study was to evaluate the PD-L1 expression in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with enzalutamide. METHODS: A total of 33 patients with mCRPC were treated with enzalutamide. All patients were previously treated by one or two lines of chemotherapy. Enzalutamide was administered in the standard dose (160 mg orally once daily as four 40 mg capsules). No corticosteroids were concomitantly administered. PD-L1 expression was determined semiquantitavely by immunohistochemistry. RESULTS: Enzalutamide was well tolerated with predominantly G1-2 toxicity. G3-4 anaemia was found in 6 patients and G3-4 thrombocytopenia in 2 patients. One patient had cerebral hemorrhage. The median progression free survival (PFS) was 7.0 months (95% CI 6.1-7.9). The median overall survival (OS) was 8.4 months (95% CI: 5.1-11.7). The shorter OS was noted in the subgroup of patients with decreasing hemoglobin levels during enzalutamide treatment with hazard ratio (HR) 0.155 (95% CI 0.053-0.449) and in patients with Gleason score 8-10 with HR 0.334 (95% CI 0.12-0.927) according to the regression analysis. All tissue samples were scored as negative in the detection of PD-L1. CONCLUSIONS: The expression of PD-L1 in prostate cancer cells as potential new predictive biomarker was not confirmed. Further studies are needed to clarify this topic.

Selected Case From the Arkadi M. Rywlin International Pathology Slide Seminar: Benign Warthin Tumor of the Thyroid.

We report on an exceedingly rare lesion of the thyroid probably of a branchial cleft origin, which was not published in the world literature before. A 58-year-old woman underwent a total thyroidectomy for bilateral goiter. Grossly, there was one yellowish nodule sized 15 mm in the largest dimension found in the right lobe. Microscopically, the thyroid parenchyma showed signs of Hashimoto thyroiditis. The nodule in the right lobe was composed of a part of solid cell nests appearance, another part resembling a branchial cleft cyst, and a part resembling Warthin tumor. This lesion may belong to the histogenetically similar group of entities in the head and neck region which are derived from branchial cleft derivatives and which, under the inflammatory influence, have the ability to a cystic dilatation and proliferation of the epithelial component. The epithelium can afterwards become papillary and may undergo oncocytic transformation, thus gaining features that impart the resemblance of a Warthin tumor. Club members generally agreed with a submitted diagnosis of benign Warthin tumor of the thyroid.

Spectrum of lesions derived from branchial arches occurring in the thyroid: from solid cell nests to tumors.

There is a group of lesions in the head and neck region derived from branchial arches and related structures which, when inflamed, are characterized by the formation of cysts lined by squamous or glandular epithelium and surrounded by a heavy inflammatory infiltrate rich in germinal centers. In the thyroid, the main source of various structures which may cause diagnostic dilemma is the ultimobranchial body. To investigate the spectrum of such thyroid lesions, the consultation files were reviewed for thyroid samples containing pathological structures regarded to arise from the ultimobranchial body. Positive reaction with antibodies against CK5/6, p63, galectin 3, and CEA, and negative reaction with antibodies against thyroglobulin, TTF-1, and calcitonin were used to confirm the diagnosis. The specific subtype of the ultimobranchial body-derived lesion was then determined based on histological examination of H&E-stained slides. Twenty-one cases of ultimobranchial body-derived lesions were retrieved from the consultation files, 20 of them along with clinical information (M/F = 6/14, mean age 55 years, range 36-68 years). Lesions derived from the ultimobranchial body were classified as follows: (hyperplastic) solid cell nests (nine cases), solid cell nests with focal cystic change (five cases), cystic solid cell nests (two cases), branchial cleft-like cyst (four cases), and finally a peculiar Warthin tumor-like lesion (one case). We suggest that the common denominator of these structures is that they all arise due to activation of inflammatory cells around the vestigial structures, which leads to cystic dilatation and proliferation of the epithelial component.