Aim: The aim of our study was to evaluate status of estrogen and progesteron hormone receptors (ER and PR), and HER2 receptors in diagnostic core biopsy specimens, compared to surgical resection specimens of the same patients after NAC regimens all including trastuzumab. Introduction: Neoadjuvant chemotherapy (NAC) is associated with phenotypic alteration in breast carcinoma, especially with the change of molecular phenotype through the modulation of hormone and HER2 receptors expression. Material and Methods: The study included 35 patients with HER2-amplified locally advanced breast carcinoma that were treated with NAC regimens that included trastuzumab, and which had receptors status determined on pre-NAC core biopsy, and on surgical specimen after the completion of the therapy. Results: Pathological complete response (pCR) was observed in 4 cases (11.4%), while partial response to therapy was noted in 31 cases (88.6%). Invasive breast carcinoma of no special type (NST) was the most common histological type in 27 cases (87.1%), while the most common histological grade (HG) was HG3 in 27 cases (87.1%). There were no noted changes in histological type or grade of the carcinoma. The rates of ER and PR receptors positivity on diagnostic core biopsy compared to post-NAC surgical resection specimens were 61.29% to 67.74% and 48.39% to 64,52%, respectively. HER2 receptors status changed from positive to negative in 2 cases (6,45%). Conclusion: Changes in status of the receptors in breast carcinoma after NAC is significant due to implications in tailored therapy approach, and subsequent modification of adjuvant therapy regimens.

Pathologists often have a dilemma is a lymph node biopsy reactive or corresponds to a lymphoproliferative or other malignant disease. In everyday routine work, we rely on morphologic criteria and immunohistochemical analyzes. In better-equipped labs additional cytogenetic and molecular methods are used if morphology and immunohistochemical analyzes are not sufficient for getting correct diagnoses. It is important to know clinical presentation and the opinion of a clinician who runs the case. In reactive lymph nodes general morphology is mostly preserved. Distribution of B and T cells, histiocytes, dendritic cells and proliferation is adequate. Foreign cells are not present. Ways of reaction in lymph nodes are follicular hyperplasia, paracortical expansion, sinus histiocytosis and granuloma formation. If metastases are present, most often from carcinomas and melanomas, the initial deposits are usually sub capsular or less often in sinuses. One should be careful to differentiate sinus histiocytes and metastatic tumor cells, what can easily be verified by immunohistochemical stains.If it is a lymphoma, one should decide is it a Hodgkin or a non-Hodgkin lymphoma. In non-Hodgkin lymphomas, one should decide between small cell and large cell lymphomas. In non-Hodgkin lymphomas, tumor cells are dominant and background inflammation is scant and mostly consisted of small T cells and rare histiocytes. In T cell lymphomas background inflammation can be quite various. In Hodgkin lymphomas background inflammation most often is various and almost always outnumbers tumor cells. Tumor cells are large, with lobulated or multiple nuclei and conspicuous nucleoli. The immunophenotype is usually clearly different from non-Hodgkin lymphomas. The differentiation of small cell and large cell non-Hodgkin lymphomas is easily made by comparing cell sizes. If tumor cell size is closer to size of histiocytes or endothelium it is a large cell lymphoma, but if it SPECIJALNA SESIJA: KATEDRA ZA PATOLOGIJU MEDICINSKOG FAKULTETA, UNIVERZITETA NOVI SAD, SRBIJA 31 MATERIA MEDICA • Vol. 34 • Issue 1, suplement 1 • april 2018. is closer to small lymphocytes and red blood cells it is a small cell lymphoma. Differentiation of small cell lymphomas is based on morphology, distribution of cells and on immunophenotype. Differentiation of large cell non-Hodgkin lymphomas requires immunohistochemical analyzes because morphology is often very similar among entities. Correct diagnosis is important due to application of optimal therapy and reaching the best prognosis for the patient.