The 5th Edition of the World Health Organization (WHO) Classification of Hematolymphoid Tumors: What's New in Pediatrics?

The World Health Organization (WHO) has revised the classification of hematolymphoid tumors (WHO-HAEM5) in August 2022 to incorporate certain recent changes in understanding of disease biology. This article highlights the important changes, with particular reference to those most relevant to children.

Splenic Lymphomas: A Tertiary Care Center Experience and Review of Literature.

Primary splenic lymphomas are rare with the majority of lymphomas in spleen being secondary to an extra-splenic lymphoma. We aimed to analyze the epidemiological profile of the splenic lymphoma and review the literature. This was a retrospective study including all splenectomies and splenic biopsies from 2015 to September 2021. All the cases were retrieved from Department of Pathology. Detailed histopathological, clinical and demographic evaluation was done. All the lymphomas were classified according to WHO 2016 classification. A total of 714 splenectomies were performed for a variety of benign causes, as part of tumor resections and for the diagnosis of lymphoma. Few core biopsies were also included. A total of 33 lymphomas diagnosed in the spleen, primary splenic lymphomas constituted 84.84% (n = 28) of the cohort with 5 (15.15%) having the primary site elsewhere. The primary splenic lymphomas constituted 0.28% of all the lymphomas arising at various sites. Adult population (19-65 years) formed the bulk (78.78%) with a slight male preponderance. Splenic marginal zone lymphomas (n = 15, 45.45%) comprised of major proportion of cases followed by primary splenic diffuse large B-cell lymphoma (n = 4, 12.12%). Splenectomy was the main course of treatment for SMZL with a good overall outcome, with chemotherapy ± radiotherapy forming the mainstay in other lymphomas. Lymphomas in spleen can be infiltrative or a primary, hence proper clinic-radiological and pathological evaluation is required. Appropriate management is guided by the precise and detailed evaluation by the pathologist, requiring understanding of the same.

A Comparative Review of ICMR, WHO, and EMA Guidelines for Good Clinical Laboratory Practices.

With the advancement of clinical research and the increased burden on laboratory services, there is an unmet need for guidelines regarding proper laboratory functioning and reliable data generation. Several organizations from all over the world have published guidelines for these clinical and research laboratories. Good Clinical Laboratory Practices (GCLP) are stepwise procedures aimed at strengthening the quality of test results produced by all clinical laboratories engaged in human sample analysis. In this article, we attempt a comparison of the GCLP guidelines recently issued by the Indian Council of Medical Research with the guidelines released by the World Health Organization and the European Medicines Agency. Also, we have included and discussed several suggestions that, if included, will lead to the strengthening of the laboratory practices used for both research and patient care for overall improvement in the Indian healthcare system.

Acute myeloid leukemia with RAM immunophenotype: A new underdiagnosed entity.

INTRODUCTION: Acute myeloid leukemia (AML) with RAM immunophenotype is a distinct subtype of AML, as described by the Children's Oncology Group (COG), with characteristic morphological and immunophenotypic properties. It is characterized by strong CD56 expression with dim to negative CD45, HLA-DR, and CD38 expression. It is an aggressive leukemia with a poor response to induction chemotherapy and/or frequent relapses. METHODS: Seven cases with the characteristic RAM immunophenotype were identified in this retrospective analysis of newly diagnosed pediatric AML cases from January 2019 to December 2021. Herein, we have critically analyzed their clinical, morphological, cytochemical, immunophenotyping, cytogenetic, and molecular profiles. The patients were traced and followed for their current disease and treatment status. RESULTS: Of 302 cases of pediatric AML (age <18 years), seven cases (2.3%) with the distinct RAM phenotype were observed, with age ranging from 9 months to 5 years. Two patients were misdiagnosed earlier as small round cell tumor because of the strong CD56 positivity and the absence of leukocyte common antigen (LCA), but they were later correctly identified as granulocytic sarcoma. The bone marrow aspirate showed blasts with unusual cohesiveness and clumping with nuclear moulding, mimicking non-hematologic malignancies. Flow cytometry revealed blasts with low side scatter, dim to negative CD45 and CD38, negative cMPO, CD36, and CD11b; moderate to bright CD33, CD117, and bright CD56. The Mean fluorescence intensity (MFI) of CD13 expression was significantly lower as compared to the internal controls. Cytogenetic and molecular studies did not show any recurrent abnormalities. Reverse transcription polymerase chain reaction for CBFA2T3-GLIS2 fusion was performed in 5/7 cases, with one positive result. On clinical follow-up, two patients were refractory to chemotherapy. Six of the seven cases had succumbed to death (duration of survival: 3-343 days after initial diagnosis). CONCLUSION: AML with RAM immunophenotype, a distinct form of pediatric AML with a poor prognosis, may pose a diagnostic challenge if presented as a soft tissue mass. A comprehensive immunophenotypic evaluation, including stem cell and myeloid markers, is critical for an accurate diagnosis of myeloid sarcoma with the RAM-immunophenotype. Our data demonstrated weak CD13 expression as an additional immunophenotypic finding.

Follicular Helper T-Cell-derived Nodal Lymphomas: Study of Histomorphologic, Immunophenotypic, Clinical, and RHOA G17V Mutational Profile.

The study was designed to review the demographic, clinical, and pathologic characteristics of follicular helper T cells (TFH)-derived nodal PTCL in India including angioimmunoblastic T-cell lymphoma (AITL), peripheral T-cell lymphoma (PTCL) with follicular helper T cell phenotype (P-TFH), and follicular T-cell lymphoma with additional immunohistochemistry (IHC) and RHOAG17V mutational analysis, as well as their impact on survival. This retrospective study included 88 cases of PTCL that were reclassified using IHC for TFH markers (PD1, ICOS, BCL6, and CD10) and dendritic-meshwork markers (CD21, CD23). Cases of TFH cell origin were evaluated for RHOAG17V mutation using Sanger sequencing and amplification-refractory mutation system-polymerase chain reaction (PCR) (validated using cloning and quantitative PCR) with detailed clinicopathologic correlation. Extensive re-evaluation with added IHC panel resulted in a total of 19 cases being reclassified, and the final subtypes were AITL (37 cases, 42%), PTCL-not otherwise specified (44, 50%), P-TFH (6, 7%), and follicular T-cell lymphoma (1, 1%). The presence of at least 2 TFH markers (>20% immunopositivity) determined the TFH origin. AITL patients tended to be male and showed increased presence of B-symptoms and hepatosplenomegaly. Histomorphology revealed that 92% of AITL cases had pattern 3 involvement. Sanger sequencing with conventional PCR did not yield any mutation, while RHOAG17V was detected by amplification-refractory mutation system-PCR in AITL (51%, P =0.027) and P-TFH (17%), which was validated with cloning followed by sequencing. Cases of RHOAG17V-mutant AITL had a worse Eastern Cooperative Oncology Group performance status initially but fared better in terms of overall outcome ( P =0.029). Although not specific for AITL, RHOAG17V mutation shows an association with diagnosis and requires sensitive methods for detection due to low-tumor burden. The mutant status of AITL could have prognostic implications and translational relevance.

Safety and Efficacy of Bendamustine and Rituximab (BR) Regimen in Indian Chronic Lymphocytic Leukaemia Patients.

We investigated the safety and efficacy of bendamustine-rituximab (BR) in previously untreated symptomatic and advanced CLL patients, as there is no data available on BR from the Indian subcontinent.This retrospective study included 120 consecutive treatment naïve patients with CLL without del (17p), who were registered at the Department of Medical Oncology, AIIMS between January 2010 and July 2018. Bendamustine was given at a dose of 90 mg/m2 on days 1 and 2, combined with rituximab 375 mg/m2 rituximab on day 1, every 28 days for up to 6 courses. Event-free survival (EFS) was defined as the date of treatment to date of relapse, disease progression, or death due to any cause.The median age was 57 years (range: 30-75 years). As per the clinical Rai stage, 30 (25%) patients were in stage II, 42 (35%) were in stage III and 48 (40%) were in stage IV. ZAP70 was positive (> 20%) in 50%, CD 38 was positive (> 30%) in 33%, and CD49d was positive (> 30%) in 49% of cases. Beta-2 microglobulin (B2M) was elevated (≥ 3.5 mg/L) in 80% of cases. Fifty-five cases (50%, n = 110) were IGHV mutated. The mean number of cycles was 5 (1-6). The overall response rate (ORR) seen with BR was 90% and complete response was 45%. Median progression-free survival was 24 months with a median follow-up period of 29 months. Haemoglobin (< 10 g/dL), elevated B2 M, unmutated IGHV had a statistically significant adverse impact on EFS on univariate analysis but on multivariate analysis, only IGHV mutation status was found to had significance on EFS. The median EFS was 27 months in IGHV mutated versus 18 months in IGHV unmutated-CLL patients (p = 0.001). Grade 3/4 neutropenia, thrombocytopenia, anemia, and infections were observed in 30.6%, 8%, and 12% respectively. The most common non-hematological toxicity was skin rash which was grade 1/2 in 24 (20%) cases and grade 3/4 in 12 (10%) cases. This is the largest study from India to demonstrate the safety and efficacy of BR in symptomatic CLL patients. BR is an effective and safe regimen in the first-line treatment of CLL. Unmutated-CLL patients have inferior EFS than mutated-CLL patients. Skin toxicity was the most common adverse effect seen in our population which was observed in around one-third of cases.

Response assessment by positron emission tomography-computed tomography as compared with contrast-enhanced computed tomography in childhood Hodgkin lymphoma can reduce the need for radiotherapy in low- and middle-income countries.

INTRODUCTION: The InPOG-HL-15-01, a multicentric prospective study, used a risk-stratified and response-based approach with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) backbone to treat children and adolescents with newly diagnosed Hodgkin lymphoma (HL) and reduce the use of radiation therapy (RT). Children/adolescents with bulky disease or inadequate response at early response assessment (ERA) after two cycles of chemotherapy were assigned to receive RT. For ERA, positron emission tomography computed tomography (PET-CT) was recommended but not mandatory in view of limited access. This study aimed to compare the impact of using contrast-enhanced computed tomography (CECT) and PET-CT on treatment decisions and outcomes. METHODOLOGY: 396 patients were enrolled and 382 had an ERA at the assigned time point. Satisfactory response was defined as Deauville score 3 or less for patients undergoing PET-CT and complete response (CR)/very good partial response (VGPR) for patients undergoing CECT. Outcomes of interest incorporate 5 year event-free survival (EFS), EFS including abandonment (EFSa), and overall survival (OS). RESULTS: At ERA, satisfactory response was documented in 277 out of 382 (72.5%) participants and this was significantly higher in PET-CT (151 out of 186, 81.2%) as compared with CECT-based assessments (126 out of 196, 64.3%) respectively (p value < .001). Amongst the 203 patients with nonbulky disease (wherein the indication for RT was entirely dependent on ERA), 96 out of 114 (84.2%) and 61 out of 89 (68.5%) patients achieved a satisfactory response according to the PET-CT and CECT (p value = .008) respectively and hence a lesser proportion of patients in the PET-CT arm received RT. Despite a lower usage of RT the 5 year OS of both groups, ERA based on CECT (91.8%) versus PET-CT (94.1%) was comparable (p value = .391) and so was the 5 year EFS (86.7 vs. 85.5%, p value = .724). CONCLUSION: Use of PET-CT as the modality for ERA is more likely to indicate a satisfactory response as compared with CECT and thereby decreases the need for RT in response-based treatment algorithm for HL-afflicted children. The reduction in the application of RT did not impact the overall outcome and plausibly would lower the risk of delayed toxic effects.

Empirical Antitubercular Treatment for Lymphadenopathy: Are We Missing Lymphoma?

OBJECTIVE: To evaluate the proportion of patients who received empirical treatment with antitubercular therapy (ATT) prior to the diagnosis of Hodgkin lymphoma (HL) in the first multicentric, prospective study on HL from India, and to assess its impact on extent of disease at diagnosis and outcomes. METHODS: Children < 18 y with biopsy proven HL were enrolled in InPOG-HL-15-01. Along with other clinical and epidemiological data, history of prior treatment with ATT was documented. All patients received treatment as per a risk-stratified, response-adapted strategy. RESULTS: Out of 396, 115 (29%) children had received ATT prior to establishing a definitive diagnosis of HL. This cohort presented with advanced-stage disease (p = 0.001) and B symptoms (p = 0.001) in a higher proportion of cases. Consequently, those children were more likely to receive 6 rather than 4 cycles of chemotherapy (p = 0.001). They were more likely to have infradiaphragmatic involvement (p = 0.001). Overall survival and event-free survival were not different. CONCLUSION: Empirical treatment with ATT in children presenting with lymphadenopathy continues to be practiced widely in India. The delay in diagnosis may contribute to children presenting with advanced-stage disease warranting more intensive treatment for successful outcomes.

Chronic active Epstein-Barr virus infection mimicking tuberculosis - A diagnostic enigma.

ABSTRACT: Chronic active EBV infection is a rare disorder prone for misdiagnosis. They present with a wide range of symptoms from indolent to aggressive clinical course. Clinico-pathological correlation with confirmation by ancillary techniques is inevitable to diagnose this disease. We present a case of a 29-year-old male with fever, weight loss, and lymphadenopathy for 6 months. Lymph node biopsy showed occasional granuloma with preserved architecture. Suspected to have tuberculosis, he received antitubercular treatment (ATT) with no response for 3 months. Subsequently, additional workup showed many EBV-positive cells in sinusoids with high serum EBV titer, confirming the difficult diagnosis of CAEBV. The present case highlights the difficulty in the diagnosis of this entity and also emphasizes the necessity to recognize this disorder in countries endemic for tuberculosis, as it is no longer bound by ethnicity and geographical boundaries.

Rosai Dorfman Disease with malignant transformation to Histiocytic Sarcoma: A diagnostic conundrum.

ABSTRACT: Histiocytic disorders mostly occur as de-novo nodal or extranodal benign masses with rare secondary malignant transformation. A 10-year-old female presented with 10-cm cervical swelling since 9 months associated with fever. Computed tomography revealed left cervical lymphadenopathy and bilateral lung nodules. Lymph node excision biopsy showed effacement of architecture by atypical histiocytes with marked nuclear pleomorphism and frequent mitosis. Focal areas showed mature histiocytes with emperipolesis. The cells were immunopositive for CD68, CD163, and S100 (focal), whereas they were negative for Langerin and CD1a. The Ki67 proliferative index was 30%. A diagnosis of histiocytic sarcoma in a background of Rosai-Dorfman disease was made.

Primary extranodal NK/T cell lymphoma of stomach: A case report and review of literature.

ABSTRACT: Extranodal Natural killer/T (NK/T) cell lymphoma nasal type is an aggressive non-Hodgkin lymphoma and has a constant association with Epstein-Barr virus (EBV) infection. Approximately more than 75% cases are located in upper aero-digestive tract, of which stomach is a very rare site. Very few cases of gastric extranodal NK/T cell lymphoma have been reported in the literature. A 22-year-old male patient presented with complaints of abdominal pain and hematemesis. Endoscopy showed a large ulcer in the stomach. Partial gastrectomy done and histopathology showed transmural infiltration by intermediate size atypical lymphoid cells which are immunopositive for CD3, CD56, TIA, EBV-encoded RNA (EBER) and negative for CD4, CD8, CD20. A diagnosis of extranodal NK/T cell lymphoma nasal type was made.

Blastic plasmacytoid dendritic cell neoplasm: A clinicopathological diagnostic dilemma report of three cases with review of literature.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a highly aggressive hematologic neoplasm and classified under acute myeloid leukemia. Here, we describe the clinicopathological features of three cases of BPDCN: two with classical and one uncommon immunophenotype. A-35-year-old female (case 1) presented with complaint of nasal mass and generalized lymphadenopathy. Biopsy from axillary lymph node showed infiltration by cells with scant cytoplasm which were immunopositive for LCA, CD4, CD43, and ALK1. Flowcytometry showed positivity for CD45, CD4, CD33, and CD123 while negative for rest all markers. The other two cases have classical immunophenotype. In clinical practice, nasal mass with lymphadenopathy suggests natural killer T-cell/peripheral T-cell lymphoma. Again immunohistochemical positivity for CD4, CD43, and ALK while negativity for CD3 suggests anaplastic large cell lymphoma. In this case, morphology and extensive bone marrow involvement raise the suspicion. Fowcytometry positivity for HLADR, CD123, and CD33 helps in making diagnosis.

Current trends in diagnosis and management of follicular lymphoma.

Follicular lymphoma (FL) originates from germinal center B cells, is the most prevalent form of indolent non-Hodgkin's lymphoma. Upfront management is based on stage, grade, and disease burden. Radiotherapy may be curative in limited disease while chemoimmunotherapy is preferred in advanced disease. Maintenance therapy is routinely administered but its role is debatable. Relapses are common and interval from initial therapy to relapse is most important prognostic factor for relapsed FL. Management of relapsed patients is based on the initial management, the interval from prior therapies, and the toxicity of available therapies. Multiple agents are available for patients after two or more lines of therapy, but sequencing remains poorly defined.

Small cell variant anaplastic large cell lymphoma presenting as leukemia: A case report and review of Literature.

Anaplastic large cell lymphoma (ALCL) is a subcategory of the mature T-cell neoplasm characterized by sheets of cluster of differentiation (CD)30-positive pleomorphic large cells mostly present as lymphadenopathy. Here, we describe a case of Small cell variant ALCL with leukemic presentation without lymphadenopathy. A 68-year-old male presented with fatigue and weakness; examination revealed a total leukocyte count of 295,000/uL. The peripheral smear showed cells having cerebriform nuclei comprising 90% of the leukocytes. The flow cytometry showed that the cells were immunopositive for CD3 (weak), CD4, CD7, and negative for the rest of the markers. The cell blocks from the peripheral blood showed cells with immunopositivity for CD30, anaplastic lymphoma kinase (ALK), and Epithelial membrane antigen (EMA). A diagnosis of the small cell variant of ALK-positive ALCL was made. Due to the presence of atypical pleomorphic cells without lymphadenopathy, the case has a diagnostic dilemma with differential diagnosis of Sezary syndrome, T-cell prolymphocytic leukemia, and adult T-cell leukemia/lymphoma. Karyotyping and additional immunohistochemistry help for the confirmation of the diagnosis.

Neoplasms of follicular helper T-cells: an insight into the pathobiology.

T-follicular helper cells (TFH) are a unique subset of T-cells with varied transcriptional profiles and functions. In the last 2016 WHO classification, lymphomas arising from TFH were included as a broad category and emphasis was given to separating them from other peripheral T cell lymphomas. The neoplasms derived from these mainly comprise angioimmunoblastic T-cell lymphoma, peripheral T-cell lymphoma with T-follicular helper cell phenotype, follicular T-cell lymphoma, and cutaneous CD4+ small-medium sized lymphoproliferative disorders. The TFH lymphomas comprise both indolent and aggressive forms. Additional immunohistochemistry to identify TFH cells like CD10, BCL6, ICOS, PD1, CXCL13 and mutations like RHOA, IDH2 is required for diagnosis and prognostication. The understanding of these has evolved over the years, and currently we review the updates and pathobiology of the above.

ALK-Negative Primary Cutaneous Anaplastic Large Cell Lymphoma With Systemic Involvement or Systemic ALCL With Cutaneous Lesion. A Diagnostic Dilemma.

ABSTRACT: Primary cutaneous anaplastic large-cell lymphoma (C-ALCL) is a cutaneous CD30-positive lymphoproliferative disorder. The patients usually present with single or multiple cutaneous nodules or papules and about 10% cases present with extracutaneous manifestations, which are predominantly in the form of regional lymph nodal involvement. Visceral involvement especially pulmonary or hepatic involvement in C-ALCL is only rarely described in the scientific literature. Approximately 20%-42% cases show spontaneous regression, about 50% cases may recur; however, C-ALCL generally carries a good prognosis. We present a rare case of primary C-ALCL in a 66-year-old man with regional lymph nodal and hepatic involvement. Differential diagnostic entities are discussed in this report with the review of the literature.