Maligne Lymphome im Kindes- und Jugendalter

[Recovery of paraffin blocks and central archiving : Experiences of the Kiel lymph node registry and the German study group for Hodgkin lymphoma]

BACKGROUND

Central collection of tissue blocks for pathological and translational research is particularly important in rare diseases. Transfer of tissue blocks from primary to central pathology is of crucial importance.

OBJECTIVES

We aimed to answer the following questions: Has the transfer of tissue blocks sent for consultation or within clinical trials changed over the last 20 years? What are the reasons for reclaiming tissue blocks by the primary pathology and what actions would convince primary pathologists to leave the blocks in the reference pathology?

MATERIAL AND METHODS

The first 100 biopsies of each year between 1995 and 2015 (n = 2100), as well as all tissue transfers within therapeutic studies (n = 1405, German Hodgkin Study Group, GHSG) between 1998 and 2015, were analyzed separately for block reclaims using the Department of Pathology database. A questionnaire evaluated the reasons for block reclaiming by the peripheral pathologists.

RESULTS

There is a significant increase in block reclaims during the period analyzed among submissions for consultation as well as in clinical trials (linear regression, p = 0.0195 and p = 0.0107). The percentage of block reclaims does not differ between consultations and cases submitted upon request within clinical trials (p = 0.2404, t-test). A survey among pathologies that reclaim the block showed that their willingness to leave the block at the reference center would increase if the compatibility with accreditation guidelines (39.3%), a positive statement from professional associations (25%), or a formal confirmation of availability (53.6%) is provided.

DISCUSSION

In particular, to improve research on rare diseases, it is desirable to point out the compatibility of central archiving in a designated center with accreditation guidelines.

[Diagnostic molecular pathology of lymphatic and myeloid neoplasms]

Molecular pathology has been an integral part of the diagnostics of tumors of the hematopoietic system substantially longer than for solid neoplasms. In contrast to solid tumors, the primary objective of molecular pathology in hematopoietic neoplasms is not the prediction of drug efficacy but the diagnosis itself by excluding reactive proliferation and by using molecular features for tumor classification. In the case of malignant lymphomas, the most commonly applied molecular tests are those for gene rearrangements for immunoglobulin heavy chains and T-cell receptors. However, this article puts the focus on new and diagnostically relevant assays in hematopathology. Among these are mutations of MYD88 codon 265 in lymphoplasmacytic lymphomas, B-raf V600E in hairy cell leukemia and Stat3 exon 21 in indolent T-cell lymphomas. In myeloproliferative neoplasms, MPL W515, calreticulin exon 9 and the BCR-ABL and JAK2 V617F junctions are the most frequently analyzed differentiation series. In myelodysplastic and myeloproliferative neoplasms, SRSF2, SETBP1 and CSF3R mutations provide important differential diagnostic information. Genes mutated in myelodysplastic syndromes (MDS) are particularly diverse but their analysis significantly improves the differential diagnostics between reactive conditions and MDS. The most frequent changes in MDS include mutations of TET2 and various genes encoding splicing factors.