Gastrointestinal stromal tumor after tyrosine kinase inhibition therapy: a review of biopsies of 34 patients with clinically suspected relapse and/or progression of the tumor.

Implementation of combined surgical and targeted therapy strategies using tyrosine kinase inhibitors improved the prognosis of patients with aggressive GISTs. The therapeutic answer may be individually different, some patients do not respond properly, or even progress in spite of the therapy. This together with intratumoral heterogeneity and possible development of secondary phenotypical and genetical changes represents a challenge for pathologists examining a biopsy of relapsed tumors and/or their metastases. For this study biopsy files of the national Slovak GIST registry were reviewed to identify patients examined bioptically both prior the therapy and during the TKI treatment due to suspected tumor relapse and/or progression. All the GIST biopsies were analyzed using a standardized algorithm of histological, immunohistochemical and molecular analyses of exon 7, 9, 11, 13 of c-KIT and exons 12, 14, and 18 of PDGFRA genes, with the aim to identify posttherapeutical changes of these parameters. From 34 patients fulfilling the criteria of selection, all were histologically examined during their clinically suspicious first GIST relaps, eight during the 2nd, three during 3rd and one during 4th and 5th relapse resp. All but one posttherapeutical biopsies showed "viable" GIST tissue and so 44 relapses of 33 patients could be evaluated in comparison with identical parameters of diagnostic biopsies. Distinguishing three major histological types (spindle-, epitheloid-cell and mixed cell type), a change of the GIST type was identified in 1/3 of 1st relapse and » of all relapse biopsies. Evaluation of three phenotypical GIST parameters CD117, CD34 and DOG-1, showed that phenotype alteration was always represented by a single change. The most common was either a gain or loss of CD34 positivity appearing in 1/3 of 1st relapse biopsies, while a loss of CD117 positivity was identified in one patient´s biopsy only. Altogether, the phenotypical changes were in » of all relapses. A changed mutational profile was recognized in 38,2% first relaps biopsies and in 33% of all relapses, the change was mostly isolated (in 10/45 relapses) and less often (in 4/45 relapses) it represented a gain of a new mutation in association with persisting original one. In conclusion, the biopsies of patients showing relapse and/or progression on TKI treatment show predominance of viable GIST cells with limited or even absent signs of scaring, as well as relatively low incidence of morphological, pheno- and genotypical changes.

Uncommon leukemic case of anaplastic large cell lymphoma diagnosed through a typical chromosomal abnormality t(2;5) with a null phenotype and aberrant expression of NG2 and CD13.

Anaplastic large cell lymphoma represents approximately 10-15 % of pediatric non-Hodgkin lymphomas. Leukemic presentation is very rare, and in particular, the null phenotype ALCL without typical anaplastic morphology together with aberrant expression of CD13 and/or CD11b represents a diagnostic challenge. We report a case of a 9 year-old boy with leukemic presentation of ALCL with the typical translocation t(2;5)(p23;q35); in this patient, the only positive antigens identified by immunophenotyping were CD13, NG2 HLA-DR, and CD38. To our knowledge, aberrant expression of NG2 has never been reported in ALCL cases (Tab. 1, Fig. 6, Ref. 20).

Solitary intrathyroid metastasis of renal cancer.

In general, it is estimated that around 1% of all clinically detectable thyroid cancers are of metastatic origin. With regard to the origin of the metastatic thyroid lesions, the most common primary sites are tumors of kidneys, breast, lungs and gastrointestinal system, and melanomas. Patients with nodular goiter and history of malignancy should be stratified into a high risk category. The authors present a patient with solitary thyroid metastasis from renal clear cell carcinoma 31 and 11 years after left and right nephrectomy and present a comprehensive review of the literature (Fig. 3, Ref. 14).

[Our experience with detection of JAK2 mutations in paraffin-embedded trephine bone marrow biopsies of patients with chronic myeloproliferative disorders]. / Nase skúsenosti s vysetrovaním JAK2 mutácií pacientov s myeloproliferatívnymi ochoreniami z trepanobioptického materiálu kostnej drene.

Polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) are Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) characterized by JAK2 mutation. The exon 14 V617F mutation is present in almost all patients with PV and in approx. 60% of patients with ET and PMF. The importance of JAK2V617F in the differential diagnostic considerations is still unclear and here the BM morphology examination still represents an important diagnostic tool. In the WHO classification of Ph1-negative MPNs, the identification of JAK2 mutations represents a major diagnostic criterion of these diseases. Therefore we decided to implement the examination of JAK2V617F mutation in formalin-fixed paraffin-embedded biopsy specimens of patients with Ph1-negative MPN using allele-specific PCR. In addition, in all JAK2 V617F negative patients with PV we sequenced the whole JAK2 exon 12. Until now we examined up to 200 patients with clinically confirmed MPN and our results in all three categories PV, ET and PMF are in agreement with earlier published data. Paraffin embedded tissues represent a valuable source of DNA which can be used in the diagnostics of both JAK2 exon 12 and exon 14 mutations. It is of particular importance if the fresh material is not available and there is a clinical and/or research utility for the performance of PCR on archival bone marrow samples with PV, ET or PMF suspicion.

[Laparoscopic distal pancreatectomy for neuroendocrine pancreatic tumors--initial experience]. / Laparoskopická distálna pankreatektómia pre neuroendokrinné nádory pankreasu--prvé skúsenosti.

INTRODUCTION: Although the first successful laparoscopic distal pancreatectomy in Martin was recorded in 2005, after five years we have successfully established this unique surgical procedure. The aim of this paper is to present two successful laparoscopic distal pancreatectomies in patients with neuroendocrine tumors of the distal pancreas. MATERIALS AND METHODS: Laparoscopic distal pancreatic resection is currently challenging many pancreatobiliary surgeons. Its open alternative is the standard surgery for tumors in the body and tail of pancreas. Laparoscopic distal pancreatectomy meets all aspects of radical oncological resection including lymphadenectomy. Similarly to open resection is often associated with splenectomy, but brings significant benefit to the patient in the form miniinvasivity. The paper gives crucial points of surgical procedure that is still an unique surgery. RESULTS: Although the last 4 months we operated on laparoscopically only 2 patients we present at least the preliminary experience with this method as well as a rich documentation of these procedures. CONCLUSION: Laparoscopic distal pancreatectomy in the hands of an experienced laparoscopic surgeon has the chance to become an alternative to an open surgery.

[Commentary on development of the prognostic factors concept in chronic lymphocytic leukaemia: the route from prognostic factors to therapy response predictors]. / Komentár k vývoju konceptu prognostických faktorov chronickej lymfocytovej leukémie: cesta od prognostických faktorov k prediktorom liecebnej odpovede.

Chronic lymphocytic leukaemia (CLL) is a lymphoproliferative disorder with variable clinical course. Determination of disease prognosis is based on the identification of different prognostic factors. The concept of CLL prognostic factors is still developing and has undergone several fundamental changes. Traditional (old) prognostic factors and staging systems are useful in describing the extent of the disease at any given moment, in determining clinical progression and in the identification of patients who need to start treatment. However, traditional prognostic factors are not sufficient for predicting a long-term prognosis because they are not able to identify potentially aggressive forms of CLL in the early stages. Nevertheless, clinical staging systems maintain their importance and in contrast to other traditional factors also their independent prognostic role. Otherwise, traditional prognostic factors play the role of disease activity descriptors rather than the role of actual prognostic factors. CLL risk profile determination is based on the identification of so-called new prognostic factors, the most relevant of which are chromosomal aberrations, TP53 gene mutations, mutational status of IgVH genes, ZAP-70 and CD38 expression. These factors are able to predict the prognosis already at the time of the initial diagnosis. In contrast to previous ideas, they are not incorporated into recommendations regarding indications for treatment. This is due to the risks associated with early treatment and the lack of data validated in prospective clinical trials demonstrating the justifiability of such procedure. In patients being treated, new prognostic factors may be useful for predicting the response to the therapy and some of them may directly influence the choice of treatment regime. New CLL treatment modalities have also raised the question of their influence on the prognostic and predictive power of new prognostic factors.

Primary B-cell pituitary lymphoma of the Burkitt type: case report of the rare clinic entity with typical clinical presentation.

Primary CNS lymphomas (PCNSLs) constitute 3% of all intracranial neoplasms. From these, primary pituitary lymphomas (PPLs) represent extremely rare clinical entity. Nearly all of PCNSLs are non-Hodgkin diffuse large B-cell lymphomas. We present a 60-year-old female with right-sided third cranial nerve palsy, mild bitemporal visual field deficit, severe cephalea, and polyuria-polydipsia. Hypopituitarism with hyperprolactinemia was confirmed; brain imaging revealed a 16 mm-diameter sellar mass with suprasellar extension. A presumptive diagnosis of pituitary adenoma was established. The patient underwent a neurosurgical intervention. Histopathological examination and immunophenotyping (cytokeratin, CD45+, CD79+, bcl-2-) verified high-grade B-cell non-Hodgkin lymphoma of the Burkitt type. Systemic work-up showed no other foci of lymphoma, the patient's HIV status was negative, Epstein-Barr virus status was not disclosed. Although PPL can be undistinguishable from pituitary adenoma at imaging, one should consider lymphoma when evaluating an invasive sellar mass that is iso- to hypointense on T2-weighted magnetic resonance images, particularly when the patient is immunocompromised or old and presents with diabetes insipidus, cranial nerve palsy and fever of unknown origin in addition to the expected finding of hypopituitarism.

Fibrosis identified in the bone marrow biopsies of patients with essential thrombocythemia: its incidence and significance for the differential diagnostic considerations.

Myelofibrosis (MF) may develop in all types of myeloproliferative disorders and its identification is of clinical relevance. Typical bone marrow (BM) morphology of patients with essential thrombocythemia (ET) shows either "normal" amount or "a slight increase" of reticulin fibers, but the published data differ in relation to the applied MF definition and ET diagnostic criterias. The aim of this study was to evaluate retrospectivelly MF in BM biopsies of 30 cases in which the diagnosis of ET was confirmed also clinically by local hematologists. In 7 of the patients not only primary but also sequential biopsy was available. The MF grade and extent were evaluated semiquantitativelly in archival slides stained by Gömöri silver impregnation. The analysis was based on the European clinicopathological criteria 2004 (ECP) defining a) normal bone marrow fibrosis (MF0), b) slight reticulin fibrosis (MF1), c) advanced reticulin and initial collagen fibrosis (MF2) and d) advanced collagen fibrosis (MF3). Generally, in majority of the biopsies MF0 (n = 6) or MF1 (n = 25, 18x focal and 7x diffuse) was found. More advanced MF2 was much less common as it was present in 6 biopsies (5x focal and 1x diffuse). In relation to the actual time of BM biopsy during course of the disease, the introductory biopsies done at the time of diagnosis (n = 18) showed 3x MF0, 14x MF1 and 1x MF2. The biopsies performed after a long time of patients observations (n = 12) showed 3x MF0, 7x MF1 and 2x MF2. In 5 of 7 sequential biopsies the progress of MF was evident, but 4 of these patients were treated by cytoreductive therapy. We conclude that the BM of patients with ET in initial phase shows either MF0 or focal slight increase of reticulin fibers (MF1). In addition, the long course of the disease and/or applied therapy may lead to more developed MF and more advanced MF stages (diffuse MF1 or MF2). Therefore their finding in the BM biopsies examined in the later phases of the disease should not exclude the diagnosis of ET.

Salivary duct carcinoma--a highly aggressive salivary gland tumor with HER-2/neu oncoprotein overexpression.

Salivary duct carcinoma (SDC) is a highly malignant salivary gland tumor with aggressive clinical behavior, and is characterized by its histological resemblance to invasive ductal carcinoma of the breast. Overexpression and/or amplification of proto-oncogene Her2/neu has been shown to influence both prognosis and treatment of breast cancer. Since salivary duct carcinoma and ductal breast carcinoma share many common characteristics, HER2/neu overexpression might also be important in SDC. However, data on the expression of c-erbB2/HER2/neu in salivary gland tumors are still scarce. Therefore, we have evaluated 15 cases of salivary duct carcinomas (SDC) for HER2/neu overexpression using immunohistochemistry with the HercepTest. Overexpression, identified as strong or moderate membrane immunostaining, was observed in all but one case of SDC in most neoplastic cells. Thus, our study suggests that anti-HER2/neu therapy with Herceptin is beneficial for patients with aggressive salivary duct carcinoma.

Effects of hyperoxia and allergic airway inflammation on cough reflex intensity in guinea pigs.

Toxic influence of high oxygen concentration on pulmonary function and structures has been known for many years. However, the influence of high oxygen concentration breathing on defensive respiratory reflexes is still not clear. In our previous experiments, we found an inhibitory effect of 100 % oxygen breathing on cough reflex intensity in healthy guinea pigs. The present study was designed to detect the effects of hyperoxia on cough reflex in guinea pigs with allergic airway inflammation. In the first phase of our experiment, the animals were sensitized with ovalbumin. Thirty-two sensitized animals were used in two separate experiments according to oxygen concentration breathing: 100 % or 50 % oxygen for 60 h continuously. In each experiment, one group of animals was exposed to hyperoxia, another to ambient air. The cough reflex was induced both by aerosol of citric acid before sensitization, then in sensitized animals at 24 h and 60 h of exposition to oxygen/air in awake animals, and by mechanical stimulation of airway mucosa in anesthetized animals just after the end of the experiment. In contrast to 50 % oxygen, 100 % oxygen breathing leads to significant decrease in chemically induced cough in guinea pigs with allergic inflammation. No significant changes were present in cough induced by mechanical stimulation of airways.

[Occurrence of myelofibrosis in individual types of chronic myeloproliferative diseases]. / Výskyt myelofibrózy pri jednotlivých typoch chronických myeloproliferatívnych ochorení.

BACKGROUND: During the course of chronic myeloproliferative disorders (CMPD), myelofibrosis (MF) represents a negative prognostic factor. The data concerning the incidence and progression of MF are rather heterogenous. OBJECTIVES: The aim of the study was to evaluate the incidence and progression of MF in cases of CMPD registered in the Consultation Center for Haematopathology Biopsies in Martin Faculty Hospital. METHODS: Fibrotic changes involving bone marrow were evaluated histologically semiquantitatively using reticulin fiber impregnation (method of Gomori). The study included 77 cases of chronic myelocytic leukemia (CML), 99 cases of polycythaemia vera (PV), 38 cases of essential thrombocythaemia (ET), and 126 cases of the fourth type of CMPD, mostly known as myelofibrosis/osteomyelofibrosis type (MF/OMF). The occurrence and degree of MF were evaluated at the time of all primary biopsies; in 52 of cases also in rebiopsy material. RESULTS: At the time of primary diagnosis, MF occurred in 37/77 (48%) cases of CML, in 27/99 (27.3%) cases of PV, in 8/38 (21%) cases of ET, and in 119/126 (94.4%) cases of MF/OMF. In repeated (secondary) biopsies, the progression of MF or evolution to MF was most common in CML and MF/OMF types. CONCLUSIONS: At the time of the CMPD diagnosis, more than 50% of cases showed the presence of MF. During the course of CMPD, the MF seems to represent a dynamic process evolving the underlying disease. The early diagnosis of MF is important for the selection of the appropriate therapeutic regimen. (Tab. 3, Fig. 2, Ref. 23.)

The influence of hyperoxia on cough reflex intensity in guinea pigs treated with bleomycin.

Inhalation of high concentration of oxygen produces a lung injury in men and experimental animals. In our previous experiment we have found suppression of cough reflex in healthy guinea pigs after an exposure to 100% O2 for 60 hours. This study was designed to find the effect of hyperoxia on cough reflex in guinea pigs with lungs damaged by bleomycin. We used 48 animals (300-400 g) in two separated experiments. 32 of them were intratracheally injected with 1.5 mg bleomycin (Bleocin, Nippon Kayaku Co., Ltd., Tokyo, Japan) for induction of lung damage according to the method described by Parizada et al (20). 16 animals were given saline, only (control). Animals of experimental group were divided into two subgroups according to the lapse of time from bleomycin application. 13 days after bleomycin application animals of the 1st subgroup (16) were exposed to 100% O2 (8) or to room air (8) for 48 h. Similarly, 20 days after bleomycin application guinea pigs of the 2nd subgroup (16) were exposed to 100% O2 (8) or air (8), respectively. Cough was provoked in conscious animals placed in bodyplethysmograph box by inhalation of citric acid aerosol (0.3 mol/L) before, then 13 or 20 days after bleomycin application, and finally at the end of 48-h exposition to 100% O2 (air). The number of coughs was counted from airflow trace recorded by pneumotachograph. Cough was also induced by mechanical stimulation of laryngopharyngeal (LPh) and tracheobronchial (TBr) region in anaesthetized animals (Urethane, 1.1 g/kg, i.p.) just after the end of oxygen exposition and was evaluated from the interpleural pressure record. The results have shown a tendency to inhibition of citric acid cough reflex in animals 13 days treated with bleomycin and exposed to 100% O2, and significant decrease in citric acid induced cough in animals 20 days treated with bleomycin and exposed to 100% O2. Significant changes were present in cough intensity induced by mechanical stimulation of TBr region of the guinea pigs airway treated with bleomycin and exposed to oxygen, too. (Tab. 1, Fig. 3, Ref: 29.)

[Functional and morphological changes in the respiratory organs of cats after long-term exposure to pure normobaric oxygen]. / Funkcné a morfologické zmeny dýchacích orgánov maciek dlhodobo exponovaných cistému normobarickému kyslíku.

BACKGROUND: Pulmonary oxygen toxicity is very well known and proved. The influence of hyperoxia on the respiratory reflexes is not known till now. MAIN PURPOSE: To ascertain if long-lasting breathing of pure normobaric oxygen (PNO) alter respiratory reflexes. METHODS: 34 adult cats of both sexes, weighing 2.5-4.0 kg, were used in two experiments. In the first experiment 16 animals with inserted chronic tracheal cannula (CTC) were used. In the second experiment 18 animals without CTC were employed. Part of animals in both experiments was exposed to PNO (day by day for 2 weeks, 10 h daily), remaining animals were exposed to room air under the same conditions. Side tracheal pressure was recorded in unanesthetized animals of the first experiment. The second experiment was performed in anaesthetised animals (Pentobarbital Spofa, 35 mg/kg, i.p.). Oesophageal pressure and blood pressure in femoral artery were recorded. Cough reflex, sneezing and aspiration reflexes were induced by mechanical stimulation of airway mucosa. Pulmonary chemoreflex was elicited by i.v. administration of 50 micrograms phenyl biguanid. Hering-Breuer inflation reflex was induced by lung inflation with pressure of 1 kPa. Reactivity of tracheal and pulmonary smooth muscle to histamine were measured in vitro. Differences in recorded parameters between animals exposed to PNO, and to room air, were tested by Mann-Whitney-Wilcoxon test and by Student's t-test. When p < 0.05, the differences were recognized as significant. RESULTS: Significant decreasing of the expiratory parameters of the cough induced from laryngopharyngeal mucosa, inhibition of sneezing, and inhibition of aspiration reflex, were found in animals exposed to PNO. Relaxing reaction of tracheal smooth muscle of control animals to histamine was reversed to contraction in animals exposed to PNO. Morphological changes of the respiratory tract induced by influence of oxygen were found CONCLUSION: Long-lasting breathing of PNO induced changes of respiratory reactions elicited mainly from upper airway.(Fig. 6, Tab. 3, Ref. 22)

[Monocytoid B-lymphocyte lymphoma: a new type within the spectrum of non-Hodgkin's B-cell lymphoma]. / Monocytoidný B-lymfocytový lymfóm: nová jednotka v spektre non-Hodgkinových lymfómov B-pôvodu.

BACKGROUND: Clonal proliferation of monocytoid B-lymphocytes (MBLy)--monocytoid B-cell lymphoma (MBCL) represents a "new" type of lymphoma within the spectrum of B-cell malignancies. OBJECTIVES: The aim of the study was to evaluate the possibilities of a routine histological and immunohistochemical diagnosis of MBCL. METHODS: Three cases of MBCL diagnosed in peripheral lymph nodes (n = 2) and in mammary gland with infiltration of regional lymph node (n = 1) were analyzed both histologically and immunohistochemically using a panel approach (Ig chains, CD30 antigen, markers of B-cells, T-cells and of monocytes/histiocytes). RESULTS: Morphological appearance of neoplastic cells of MBCL is identical to that of MBLy in reactive conditions--kidney-shaped nuclei, bright clear PAS-negative cytoplasm, and small inconspicuous nucleoli. CONCLUSIONS: Morphological appearance together with immunophenotypic results (positivity of CD20 and Ki-B5, negativity of CD3, CD43, CD45RO, and of lysozyme, negativity of CD30) are considered to represent sufficient diagnostic criteria of MBCL, including its differential diagnosis of other B-cell low grade malignancies. An increase of large cell type MBLy might represent a feature of a secondary blastic transformation of MBCL. (Tab. 2, Fig. 5, Ref. 27.)

[Primary MALT-type malignant lymphomas of the salivary glands]. / Primárne malígne lymfómy slinnej zl'azy typu tzv. lymfómu MALT-u.

Six cases of primary extranodal lymphomas in big salivary glands, which met criteria of MALT lymphoma, were investigated with the aid of antibodies against Ig, light chains, LCA and EMA, in addition in two cases against Ig heavy chains and with antibodies KL-1 and VCHL-1. All the tumours had centrocytoid morphological features, one of them showed signs of focal blastic transformation into centrocytoid centroblastoma. Tumour cells showed twice plasmacytic and three times plasmacytoid differentiation with intracytoplasmic Ig monoclonality (once IgM/kappa, once IgA/kappa, three times kappa positivity). They were positive in reaction against epimyoepithelial proliferation. A picture of myoepithelial sialoadenitis with partial lymphomatous infiltration prevailed in two cases and a lymphoma picture with remnants of sialoadenitis in three cases. Features of inflammatory process were lacking in a case with blastic transformation. There is a dispute whether features of sialoadenitis belong to the defining criteria of MALT type lymphoma or can disappear during blastic transformation of a low grade malignant lymphoma.

[Histocytopathology of monocytoid B-lymphocytic lymphoma]. / Histocytopatológia monocytoidného B-lymfocytového lymfómu.

It is generally accepted, that the cells of non-Hodgkin's lymphomas represent a neoplastic counterpart of corresponding reactive cells. The aim of this study was to compare histocytology of 6 cases of monocytoid B-cell lymphoma (MBCL) with that of reactive monocytoid B-cells of "common" and large cell type. All the lymphomas were diagnosed in peripheral lymph nodes by histology and immunohistochemistry. Histocytological appearance of MBCL corresponded mostly to that of "common typ" MBLy (n=5) with. signs of plasmacytic differentiation (p = 3/5) or rarely (n=1) with increase of intermingled blast cells. Rebiopsy of one of the cases of the "common" cell type showed a progression to a large cell high grade lymphoma of the appearance similar to the large cell type of reactive MBCs. It is therefore to be accepted that the cells of MBCL including its high grade transformation might represent neoplastic counterparts of the reactive MBLy of the "common" and large cell type respectively.

[Monoclonal plasmacytic differentiation in small-cell lymphomas of B-cell origin: immunocytoma versus other types]. / Monoklonálna plazmocytárna diferenciácia v malobunkových lymfómoch B-pôvodu: Imunocytóm versus iné typy.

We have studied the morphological and immunohistochemical features of monoclonal cytoplasmic Ig (c-Ig) production in the biopsy material of 161 small B-cell non-Hodgkin's lymphomas to verify a frequency of the plasmacytic/plasmacytoid differentiation of tumor cells for the aims of their differential diagnosis. The analyzed differentiation was identified in all the cases of immunocytoma (n = 20/20), in 2/3 of MALT-lymphomas (n = 24/38) and 1/2 of monocytoid B-cell lymphoma cases (n = 4/7), in 1/5 of centroblastic-centrocytic lymphoma cases (n = 12/60) and rarely in centrocytoma (n = 4/36). We conclude that a plasmacytic differentiation is not an unique feature of the immunocytoma. For the differential diagnosis, a histological analysis and not a proof of monoclonal c-Ig itself seems to be decisive. The obtained results are discussed in relation to the histogenesis of small B-cell lymphomas, which represent a neoplastic counterpart of the reactive B-cells at different stages of their maturation and differentiation.

[Mantle cell lymphoma (MCL)--histopathology and clinical features]. / Lymfom z plást'ových bunek (MCL)--histopatologické a klinické znaky.

Mantle cell lymphoma (MCL) has been established as a clinicopathologic entity in 1991. A histopathologic and immunohistochemical study of 16 cases of MCL was performed in order to demonstrate differential diagnostic aspects. MCLs were composed of small and medium-sized B cells assuming the appearance of centrocytes. The growth pattern was diffuse in 9 cases and that of follicle mantle zone type within at least partially present nodular parts in 16 cases. The immunohistochemical staining for CD23 antigen was negative in tumour cells whereas the strong immunoreactivity of follicular dendritic cells (FDC) decorated residual FDC network. Seven cases of MCL were examined for the presence of translocation t(11;14)(q13;q32) using polymerase chain reaction. Despite histomorphological features compatible with a diagnosis of low-grade lymphoma, MCL has a worse prognosis and more aggressive behaviour than other types of small cell lymphomas, such as small lymphocytic lymphoma and follicle centre lymphoma.

[Primary mediastinal (thymus) large B-cell lymphoma: clinically defined type of tumors and morphologic variants]. / Primárny mediastinálny (týmusový) vel'kobunkový B-lymfóm: klinicky definovaný typ nádoru a jeho morfologické varianty.

In the WHO lymphoma classification, primary mediastinal (thymic) large B-cell lymphoma (PMVBL) is defined as a subtype of diffuse large B-cell lymphoma (DLBCL) showing typical clinical manifestation. The patterns related to variability of tumor cell morphology were analyzed in the setting of 15 bioptically verified PMVBL cases. In the majority of the cases (n = 12), the tumor showed pleomorphic blastic morphology with individual cell patterns resembling those of polymorphic centroblastoma of the Kiel classification. In addition, some of the cases had clear-cell and/or lacunar appearance (5/12), while distinctive anaplastic appearance was rare (1/12). Other cases (n = 3) showed a monotonous morphology of uniform smaller-sized blasts with monocytoid-like cytoplasm. The described morphologic variants of PMVBL might be related to the known genotypic variability of DLBCL, although monotypic c-Ig expression verified in some of the cases would support post-follicular stage of the tumor cell development. In the absence of clinical data and within the described morphologic variability, it is recommended to prefer a diagnosis of DLBCL and to include the tumor into a clinically defined subtype of PMVBL only in cases with well defined and typical clinical presentation and progression of the disease.

[Primary hepatosplenic T-cell (gamma delta) lymphoma: morphology and immunohistochemistry in 3 cases]. / Primárny hepatosplenický T-bunkový (gamma delta) lymfóm: morfologický obraz a imunohistochemický profil troch prípadov.

We analyzed one autopsy case and two biopsy cases of primary (hepato-)splenic lymphoma, diagnosed in numerous trephine bone marrow, spleen and liver biopsies. It is a distinctive "new" type of a rare T-cell lymphoma characterized usually by rearrangement of gamma delta chains of T-cell receptor. Morphologically, the lymphoma is composed of a cytologically monotonous proliferation of small to medium sized lymphocytes, with diagnostically characteristic intrasinusoidal spread in the bone marrow, spleen and liver. The involvement of the lymph nodes is always absent. Immunohistochemically, the tumor cells expressed constant CD3 positivity and negativity for B- and myelomonocytic antigens, together with an inconstant coexpression of CD43 and CD45RO. In contrast to other and more common primary B-cell splenic lymphomas, its biological behaviour is more aggressive.