Session 7 of the Society for Hematopathology/European Association for Haematopathology Workshop was devoted to case presentations and discussion of enteropathy-type T-cell lymphoma (ETL) and other T-cell lymphomas involving the gastrointestinal tract. ETL is a rare type of T-cell lymphoma, often associated with a history of celiac disease, that usually arises in the jejunum but can involve other gastrointestinal tract sites (eg, stomach and colon). As the cases submitted illustrate, there are 2 histologic groups of ETL that correlate with clinical and immunophenotypic features. Pleomorphic-anaplastic ETL is usually associated with a history of celiac disease and histologic evidence of enteropathy and is most often CD56-. Monomorphic ETL often occurs without a history of celiac disease, has variable histologic evidence of enteropathy, and is usually CD56+. Comparative genomic hybridization has shown recurrent chromosomal gains and losses that are characteristic of ETL and uncommon in other T-cell lymphomas, providing useful ancillary data for the diagnosis of ETL.

Follicular lymphoma (FL) is a B-cell non-Hodgkin lymphoma that is characterized in approximately 85% of cases by the chromosomal translocation t(14;18) involving BCL2. While FL3b generally lack the t(14;18), this translocation is also absent in 15% of FL grades 1, 2 and 3a. The current study was designed to identify the frequency of t(14;18)-negative FL in a series of 166 cases of FL1, 2 and 3a in which global gene expression profiles had been established previously (Dave et al., NEJM351:2159–69, 2004). Furthermore, we sought to compare genetic alterations and gene expression profiles between FL with and without the t(14;18). Combined polymerase chain reaction (PCR) and tissue microarray-based fluorescence in situ hybridization (FISH) identified 17 t(14;18)-negative FL cases in this series (9%). Virtually all FL cases carrying the t(14;18) showed BCL2 expression by immunohistochemistry (Dako, clone 124), whereas 11 of the FL cases without a t(14;18) were BCL2-negative at the protein level. Clinically, there was no difference between the t(14;18)-negative and -positive FL subgroups regarding age and gender distribution as well as in median survival times. Comparative genomic hybridization (CGH) in the 166 FL cases revealed a characteristic pattern of chromosomal gains and losses, as previously described. However, significant differences were observed between the t(14;18)-negative and -positive FL subgroups. Specifically, the t(14;18)-positive FL subgroup showed gains of chromosomes 18q (18%), 8q (12%) and X (13%), as well as losses of 13q (16%) and 10q (16%), whereas none of these aberrations were observed in the t(14;18)-negative FL cases. To compare gene expression between the two groups, we used gene set enrichment analysis (GSEA), BRB array tools and a two-sided t-test. Cell cycle-associated genes were found to be enriched in the t(14;18)-negative FL subset. These differences were even more pronounced in FL cases that lacked both the t(14;18) and BCL2 expression at the protein level. Importantly, genes expressed in non-malignant bystander cells appeared also differentially enriched and a cytotoxic gene expression signature was found to be more prominent in t(14;18)-negative FL. These findings point to a different composition of the non-neoplastic cells in t(14;18)-positive and -negative FL and could indicate subtle differences in the immunological microenvironment of t(14;18)-negative FL.

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Introduction Static telepathology (TP) was used to support a hospital in Tanzania that cannot employ a resident pathologist but has a basic laboratory. Histological slides were prepared by the local technical staff and digital images were uploaded into an Internet-based system; consultant pathologists in Germany could give their opinion. The aim of the study was to examine the diagnostic validity of this project without local pathologists. Methods The set-up period for special training of local technical assistants was 10 weeks. Diagnoses of the first 545 cases that were processed via TP were compared with the results of a second opinion on the basis of routine slides created from the corresponding paraffin blocks, which were sent to Germany. Results Of all cases, 384 (70%) TP diagnoses were completely confirmed by the second opinion. Minor deviations (e.g. divergent subtypes of tumours or other aetiology of non-specific reactive processes) were documented in 76 cases (14%), so that overall, 84% of diagnoses were useful in the setting of the available therapeutic possibilities. The results were better in some subgroups of diseases (90–100% useful diagnoses) and suboptimal (minimum 63%) in a few subgroups with rare diseases. Thirty (5%) malignant diseases were primarily misinterpreted as being benign and 12 (2%) benign diseases as malignant. Forty-three (8%) cases were insufficient for diagnosis using TP and could not be provided with a primary assessment. Discussion Static TP can help support medical services in low-income countries in the absence of local pathologists with a potentially high diagnostic validity, especially for selected groups of diseases. The procedure can significantly improve the diagnostic procedures before commencement of therapy – a substantial contribution within a globalised world.

Background/Objective: In a project of telepathology (TP) between German pathologists and a hospital in Tanzania, trained technical assistants have uploaded digital histological images onto the internet-based platform ipath. The diagnoses from 486 paediatric specimens were analysed. Methods: The investigation included diagnoses, either primarily done via TP or secondarily after a further workup of the paraffin-embedded tissue, which was sent to Germany for cases which could not be solved via TP. In the latter, the initial TP-diagnoses were compared with the results after re-evaluation. Results: The median age was 11 years. The cohort comprised 390 benign diseases (80.2%) and 96 malignant diseases (19.8%). For benign diseases, the most frequent anatomic sites were lymph nodes, skin, and soft tissue, breast, and head&- neck. Frequent diagnoses were non-specific inflammations and benign tumors. In malignant diseases, the most sites were lymph nodes, skin, soft tissue, head&neck, and ovary and the most frequent diseases sarcomas and lymphomas. The paraffin embedded tissue of 179 cases (36.3%) was shipped to Germany. With the concordance analysis, we could discover the man- datory necessity for the possibility of second opinion in difficult cases. Conclusion: An exclusively TP-support cannot meet all requirements of modern medical diagnostics. The education of local pathologists is imperative. Keywords: Telepathology; low income country; ipath; paediatric.