Prognostic Significance of in situ Phenotypic Marker Expression in Diffuse Large B-cell Lymphomas

Diffuse large B-cell lymphomas (DLBCL) are the most common lymphoid malignancies, and encompass all malignant lymphomas characterized by large neoplastic cells and B-cell derivation. In the last decade, DLBCL has been subjected to intense clinical, phenotypic and molecular studies, and were found to represent a heterogeneous group of tumors. These studies suggested new disease subtypes and variants with distinct clinical characteristics, morphologies, immunophenotypes, genotypes or gene expression profiles, associated with distinct prognoses or unique sensitivities to particular therapy regimens. Unfortunately, the reliability and reproducibility of the molecular results remains unclear due to contradictory reports in the literature resulting from small sample sizes, referral and selection biases, and variable methodologies and cut-off levels used to determine positivity. Here, we review phenotypic studies on the prognostic significance of protein expression profiles in DLBCL and reconsider our own retrospective data on 301 primary DLBCL cases obtained on a previously validated tissue microarray in light of powerful statistical methods of determining optimal cut-off values of phenotypic factors for prediction of outcome

Normales Knochenmark und häufige reaktive Veränderungen

Zusammenfassung: Die histologische Knochenmarkuntersuchung spielt, wegen ihrer großen Aussagekraft bei relativ geringem Aufwand eine bedeutende Rolle in der Diagnostik von hämatologischen und nichthämatologischen Erkrankungen. Dafür ist die Kenntnis des normalen Knochenmarks mit seiner individuellen, insbesondere altersabhängigen, Variabilität, unentbehrlich. Neben entnahmebedingten Artefakten, die falsch interpretiert werden können, oder suboptimal fixierten bzw. verarbeiteten Biopsien, die diagnostisch überbewertet werden, gibt es eine Vielfalt von reaktiven Knochenmarkveränderungen, die einen neoplastischen Prozess vortäuschen und zu schwerwiegenden diagnostischen Fehlern führen können. Bei derartigen nichtneoplastischen Veränderungen können ein oder auch mehrere Kompartimente der Hämatopoiese qualitativ und quantitativ betroffen sein. Es kann zu Verteilungs- bzw. Architekturstörungen und/oder zu Veränderungen des Knochenmarkstromas kommen. Eine optimale Knochenmarkdiagnostik erfordert, neben Spezialfärbungen, zusätzlich oftmals immunhistochemische Untersuchungen und manchmal molekularpathologische Analysen. Mehr als bei anderen Organbiopsien ist die Kenntnis klinischer Befunde, insbesondere vorangegangener Therapien, relevant, um eine korrekte Diagnose zu stellen. In diesem Beitrag sind neben dem normalen Knochenmark die häufigsten reaktiven Veränderungen dargestell

Systemic mastocytosis with associated myeloproliferative disease and precursor B lymphoblastic leukaemia with t(13;13)(q12;q22) involving FLT3.

Systemic mastocytoses represent neoplastic proliferations of mast cells. In about 20% of cases systemic mastocytoses are accompanied by clonal haematopoietic non-mast cell-lineage disorders, most commonly myeloid neoplasms. A case of systemic mastocytosis carrying the characteristic mutation at codon 816 (D816V) in the KIT gene of mast cells, with two concurrent accompanying clonal haematopoietic non-mast cell-lineage disorders, chronic myeloproliferative disease, unclassifiable and precursor B lymphoblastic leukaemia is documented. Both accompanying clonal haematopoietic non-mast cell-lineage disorders carried the wild-type KIT gene, but had a novel t(13;13)(q12;q22) involving the FLT3 locus at 13q12. The chronic myeloproliferative disease, unclassifiable and the precursor B lymphoblastic leukaemia were cured by syngenous stem cell transplantation, but the systemic mastocytosis persisted for more than 10 years. The additional impact of molecular techniques on the correct diagnosis in haematological malignancies is highlighted, and evidence is provided that, apart from internal tandem duplications and mutations, FLT3 can be activated by translocations

Rare KIT (CD117) expression in multiple myeloma abrogates the usefulness of imatinib mesylate treatment

Background: Imatinib mesylate blocks the tyrosine kinase activity of KIT (CD117) and is an effective treatment for gastrointestinal stromal tumors. In multiple myeloma, KIT expression has been detected by flow cytometry in about 33% of specimens, but no previous immunohistochemical assessment has yet been made of the expression pattern of KIT. Materials and methods: We performed immunohistochemical analyses of 100 patients, including 72 with multiple myeloma (MM), 8 with lymphoplasmacytic lymphoma (LPL), 10 with monoclonal gammopathy of undetermined significance (MGUS) and 10 with reactive plasmocytosis. One KIT-positive MM was sequenced using polymerase chain reaction analysis. Results: In MM, only 2 cases (2.8%) were KIT positive. The great majority of the cases (97, 2%) did not express the KIT receptor tyrosine kinase. No mutation of the c-kit gene was detected. Conclusions: KIT expression is a rare event in MM and not detectable in MGUS and LPL. Therefore, treatment with imatinib is unlikely to be effective in these patient

An unusual pseudolymphoma in the context of necrotizing fasciitis: A case report.

RATIONALE The diagnosis of lymphoma in routine diagnostics can be challenging due to clinical, morphological and immunphenotypical overlap with unusual reactive processes termed "pseudolymphomas." PATIENT CONCERNS 45-year-old male that underwent surgical debridement for a necrotizing fasciitis of the thigh with concomitant excision of a regional lymph node. DIAGNOSES The lymph node demonstrated an architecture-effacing activation and proliferation of lymphoblasts and was initially misdiagnosed as an aggressive lymphoma. Only in consideration of the clinical context and with the help of additional immunohistochemical and molecular analyses the final diagnosis of a reactive lymphadenopathy could be made. INTERVENTIONS No further therapy was required after the final diagnosis of a reactive lymphadenopathy was made. OUTCOMES The clinical follow-up was unremarkable, with no evidence of residual disease after 6 months. LESSONS This case report adds the parafollicular activation and proliferation of blasts and plasmablasts in the drainage area of an active infection to the spectrum of "pseudolymphomas" and reiterizes the importance of placing histopathological findings in the proper context

Fatal scuba diving incident with massive gas embolism in cerebral and spinal arteries

CT and MRI have the potential to become useful adjuncts to forensic autopsy in the near future. The examination of fatal injuries facilitates a profound experience in the clinical-radiological examination of these cases; the more severe findings in corpses with autopsy verification can help one to understand the tiny signs seen in clinical cases of surviving victims. We present the case of a 44-year-old male diver who died from severe decompression sickness after rapid ascent from approximately 120m. Post-mortem CT and MRI studies of the brain and spinal cord revealed extensive gas inclusions in cerebral arteries, spinal arteries and cerebrospinal fluid (CSF) spaces, while the intracranial venous sinuses remained unaffected. These findings were confirmed at autopsy. Appropriate imaging techniques can help forensic pathologists to aim their autopsies at findings that might otherwise remain undetecte

Maximum intensity projection of cranial computed tomography data for dental identification

Dental radiographs play the major role in the identification of victims in mass casualties besides DNA. Under circumstances such as those caused by the recent tsunami in Asia, it is nearly impossible to document the entire dentition using conventional x-rays as it would be too time consuming. Multislice computed tomography can be used to scan the dentition of a deceased within minutes, and the postprocessing software allows visualization of the data adapted to every possible antemortem x-ray for identification. We introduce the maximum intensity projection of cranial computed tomography data for the purpose of dental identification exemplarily in a case of a burned corpse. As transportable CT scanners already exist, these could be used to support the disaster victim identification teams in the fiel

Primäres zerebelläres T-Zell-Lymphom

Zusammenfassung: Primäre T-Zell-Lymphome des zentralen Nervensystems (ZNS) sind selten. Sie müssen differenzialdiagnostisch von reaktiven Läsionen unterschieden werden. Die Diagnosestellung sollte integrativ unter Verwendung von immunhistochemischen, molekulargenetischen und/oder zytogenetischen Methoden erfolgen. Wir beschreiben den Fall eines 50-jährigen Mannes, bei welchem ein primäres zerebelläres T-Zell-Lymphom diagnostiziert und eine klonale T-Zell-Rezeptorgen-Umlagerung nachgewiesen wurde. Nach 2Zyklen Chemotherapie entwickelte der Patient eine Pneumozystis-carinii-Pneumonie und verstarb 10Wochen nach Diagnosestellung. Die Autopsie ergab keinen Residualtumor im ZN