Follicular variant of peripheral T cell lymphoma with mediastinal involvement in a child: a case report

Incidence and clinicopathological features of Follicular T-cell lymphoma in Finland; a population-based immunohistochemical study

Follicular T-cell lymphoma (FTCL) is a rare subtype of mature T-cell lymphoma. It was recently recognized as a separate lymphoma entity in the 2017 revised 4th edition of the WHO classification. The main goals of the present study were to gain better knowledge of the incidence and histopathological and clinical features of FTCL in Finland. In this study, we reviewed all angioimmunoblastic T-cell (AITL) and peripheral T-cell lymphomas, not otherwise specified, from the patient records in three hospital districts in Finland over a 10-year period, to identify FTCL cases and estimate its incidence. Five patients rediagnosed with FTCL and thirty-four with AITL were analyzed. Hodgkin/Reed-Sternberg (HRS)-like cells were observed in 24 of the 34 AITL cases and 4 of the 5 FTCL cases. We found that the main features that differentiated FTCL from AITL were the presence of clear cells, rosetting of T-cells around HRS-like cells, follicular dendritic cell meshwork, and T-cell monoclonality. Our estimated incidence of FTCL is 0.20 per 100,000 people in Finland.

Primary Mediastinal Nodal and Extranodal Non-Hodgkin Lymphomas: Current Concepts, Historical Evolution, and Useful Diagnostic Approach: Part 2

Primary mediastinal non-Hodgkin lymphomas (PM-NHLs) represent ∼5% of all non-Hodgkin lymphomas (NHLs) and comprise lymphomas of B-cell and T-cell origin. PM-NHLs are defined as involvement of mediastinal lymph nodes, thymus, and/or mediastinal organs (heart, lung, pleura, pericardium) by NHL without evidence of systemic disease at presentation. The clinical scenario is variable and depends on the lymphoma subtype. The radiologic presentation is also variable ranging from a mediastinal mass with or without superior vena cava syndrome, a pleural or a cardiac mass associated with effusion, or as an effusion only. The diagnosis of PM-NHLs can only be established by microscopic evaluation, and therefore, general pathologists should be aware of these tumors and familiar with their diagnostic approach. The most common anterior mediastinal NHLs (90% to 95%) are primary mediastinal (PM) large B-cell lymphoma and T-lymphoblastic lymphoma. Thymic marginal zone lymphoma and mediastinal gray zone lymphoma are very rare. The remainder PM-NHLs involving middle or posterior mediastinum include diffuse large B-cell lymphoma (DLBCL) and rare cases of T-cell lymphoma, including anaplastic large cell lymphoma and breast implant-associated anaplastic large cell lymphoma extending to the anterior mediastinum. Primary pleural and cardiac NHLs are mostly DLBCLs. Other rare subtypes of PM-NHLs include DLBCL associated with chronic inflammation/pyothorax-associated lymphoma, fibrin-associated DLBCL (both Epstein-Barr virus positive), and pleural and/or pericardial primary effusion lymphoma (human herpesvirus-8 positive/Epstein-Barr virus positive). We review the historical aspects, epidemiology, clinicoradiologic features, histopathology, immunohistochemistry, differential diagnosis, and relevant cytogenetic and molecular features of the remaining mediastinal B-cell lymphomas, including primary thymic marginal zone lymphoma of the mucosa-associated lymphoid tissue type, other PM small B-cell lymphomas, PM plasmacytoma, and the most relevant PM T-cell lymphomas.

Primary epiglottic follicular variant of peripheral T-cell lymphoma

The follicular variant of peripheral T-cell lymphoma, not otherwise specified, is very rare. Primary epiglottic follicular variant of peripheral T-cell lymphoma is extremely rare in clinical practice. Here, we report the first case of a follicular variant of peripheral T-cell lymphoma not otherwise specified in a 44-year-old Chinese man, who presented with a tumor in the middle of the epiglottis tongue surface. Microscopically, the tumor had a vague nodular growth pattern and the morphology of the nodules was different from each other at low power. Atypical lymphoid cells were medium to large in size and had round nuclei, with an irregular nuclear membrane, distinct nucleoli, and rapid mitotic activity. Plasma cells were found surrounding the nodules. The tumor cells were positive for follicular helper T-cell markers (CD10, PD-1, CXCL13, and BCL-6). The EBER was negative by in situ hybridization. Polymerase chain reaction-based analysis showed monoclonal rearrangements of TCRβ, TCRγ, and polyclonal rearrangements of IgH, IgK, and IgL. The clinical and imaging features and the prognostic factors of FV PTCL-NOS remain poorly understood. Thus, investigation of more cases and longer follow-up is necessary to understand the disease and to identify the best treatment to improve prognosis.

Cytotoxic Molecule-positive Epstein-Barr Virus-associated Peripheral T-cell Lymphoma in a 20-Month-old Child: A Case Report and Review of the Literature

Peripheral T-cell lymphoma (PTCL) is rare in children. Expression of cytotoxic molecules (CM) in nodal PTCL has unique clinicopathologic features, including an Epstein-Barr virus (EBV) association. However, CM+, EBV-associated PTCL is extremely rare in the childhood, with only 1 study having been reported to date, including both pediatric and adult patients. We report a case of CM+ PTCL in a 20-month-old boy with left neck lymphadenopathy as well as multiple visceral lesions. A biopsied lymph node was diffusely infiltrated by atypical lymphoid cells with a CD4/CD8, granzyme B+, perforin+, and TIA-1+ phenotype, and EBV positivity by in situ hybridization. Rearrangements of the TCR γ-chain and β-chain genes were demonstrated by polymerase chain reaction. Ancillary genetic studies detected trisomy 2, trisomy 10, a structurally abnormal 6p, and additional copies of the IRF4 gene. Multiple bone marrow biopsies failed to show any evidence of tumor, histiocytic hyperplasia, or hemophagocytosis. This lesion was therefore diagnosed as "CM+, EBV-associated high-grade peripheral T-cell lymphoma." After 5 cycles of chemotherapy, the patient was in remission 8 months following initial diagnosis. To our knowledge, this represents the youngest child with this rare tumor in the published literature, and showing an unusually favorable initial response to therapy.