BackgroundIndolent T-cell proliferative disorder of the GIT is a rare and provisional entity in the revised WHO 2016 classification. The patients usually have prolonged survival with persistent disease even without any treatment.Case presentationThe 46 years old male patient has been followed up for more than 6 years without chemotherapy. Repeated gastrointestinal biopsies showed expansion of the lamina propria extending to the submucosa by small to medium sized lymphocytes with minimal cytologic atypia. The lymphoid cells were positive for CD3, CD43, TIA-1, CD2, CD7 and the B-cell marker CD20; but negative for CD4, CD8, PAX5, CD56, cyclinD1, granzyme (GraB) and Epstein Barr virus-encoded RNA (EBER). Ki-67(MIB1) index was less than 10%. Molecular tests demonstrated a clonal rearrangement for T-cell receptor γ (TCR γ) gene but immunoglobulin chain (IgH, IgK, IgL) gene remained germline. Recognition of possible aberrant CD20 expression in indolent T-cell LPD is important to avoid potential diagnostic pitfall and improper treatment.ConclusionsWe present an unusual case of indolent T-cell lymphoproliferative disorder with aberrant CD20 expression, Recognition of this unusual immunophenotype of indolent T-cell LPD of GI helps to eschew misdiagnosis of B-cell and other high grade lymphomas and inappropriate aggressive treatment.

A comparative study of Kimura's disease and IgG4-related disease: similarities, differences and overlapping features Aims: To compare the fibroinflammatory diseases Kimura's disease (KD) and immunoglobulin (Ig)G4related disease (IgG4RD) and to explore their possible relationship. Methods and results: Forty-six cases of KD and 29 IgG4RD from our institution diagnosed from 2011 to 2020 were studied. They were compared with each other on clinical, pathological and immunohistological features. There were similar clinical features, except that IgG4RD affected an older patient population, with more frequent salivary gland involvement and KD affected head and neck lymph nodes, and showed blood eosinophilia more frequently than IgG4RD. IgG4RD exhibited frequent storiform fibrosis and obliterative phlebitis, while KD showed more frequent tissue eosinophilia, eosinophilic abscess, germinal centre eosinophilic deposit and vascularisation. Twenty to 30% of KD had more than 50 IgG4 + plasma cells (PC) per high-power field (HPF) and IgG4/IgG + PC ratio exceeding 40%. These parameters, however, occurred in 100% of IgG4RD. Significantly more KD had >10 IgE + PC/HPF and lymphoid germinal centre IgE reticular staining compared to IgG4RD. All these histological and immunohistological features are overlapping in the two diseases, although they differed with statistical significance. Conclusion: Our study confirmed that there is significant overlap in clinical, pathological and immunohistological features between KD and IgG4RD. It is important to recognise these overlapping features, and correlation with a clinicopathological picture is required in differential diagnoses. The overlapping features also suggest a possible close relationship between KD and IgG4RD, which could represent different facets of a continuous fibroinflammatory disease spectrum.