The Pathological Spectrum of Systemic Anaplastic Large Cell Lymphoma (ALCL)

ALK-positive anaplastic large cell lymphoma in adults

ALK-positive anaplastic large cell lymphoma (ALCL) represents approximately 6-7% of the mature T-cell lymphomas. This subtype contains a translocation between the ALK gene on chromosome 2 and one of several other genes that together form an oncogene. The most frequent translocation is t(2;5) which combines ALK with NPM1. This lymphoma has a median age of 34 years, is more common in males, and is in advanced stage at the time of diagnosis in most patients. ALK-positive ALCL is the most curable of the peripheral T-cell lymphomas. The CHOP regimen has been most frequently used, but results are improved with the substitution of brentuximab vedotin for vincristine (BV-CHP) and the addition of etoposide (CHOEP), with BV-CHP being favored. Salvage therapies include allogeneic or autologous bone marrow transplantation, BV, if not used as part of the primary therapy, and ALK inhibitors. The latter are very active and likely to be incorporated into the primary therapy.

The plasticity of biocompatibility

Biocompatibility concerns the phenomena that occur within the interactions between biomaterials and human patients, which ultimately control the performance of many facets of medical technology. It involves aspects of materials science, many different forms of engineering and nanotechnology, chemistry, biophysics, molecular and cellular biology, immunology, pathology and a myriad of clinical applications. It is not surprising that an overarching framework of mechanisms of biocompatibility has been difficult to elucidate and validate. This essay discusses one fundamental reason for this; we have tended to consider biocompatibility pathways as essentially linear sequences of events which follow well-understood processes of materials science and biology. The reality, however, is that the pathways may involve a great deal of plasticity, in which many additional idiosyncratic factors, including those of genetic, epigenetic and viral origin, exert influence, as do complex mechanical, physical and pharmacological variables. Plasticity is an inherent core feature of the performance of synthetic materials; here we follow the more recent biological applications of plasticity concepts into the sphere of biocompatibility pathways. A straightforward linear pathway may result in successful outcomes for many patients; we may describe this in terms of classic biocompatibility pathways. In other situations, which usually command much more attention because of their unsuccessful outcomes, these plasticity-driven processes follow alternative biocompatibility pathways; often, the variability in outcomes with identical technologies is due to biological plasticity rather than material or device deficiency.

Differentiating fulminant EBV infection complicated by HLH from Lymphoma: report of a case and a brief literature review

Epstein-Barr virus (EBV) infection may present with fulminant constitutional symptoms, cytopenia(s), and systemic lymphadenopathy, raising clinical suspicion for lymphoma and prompting lymph node and bone marrow biopsies. At the microscopic level, the histopathologic findings in cases of acute EBV lymphadenitis may mimic certain lymphoid neoplasms, creating a range of differential diagnoses and diagnostic pitfalls.We present a case of fulminant EBV infection in an adolescent whose clinical and radiographic findings led to lymph node and bone marrow biopsies to rule out lymphoma. One week after being diagnosed with acute EBV infection (infectious mononucleosis), a 17-year-old Caucasian male presented with worsening symptoms including persistent fever, progressive, painful lymphadenopathy, and splenomegaly. A peripheral blood smear showed lymphocytosis with many reactive lymphocytes, anemia, and thrombocytopenia. Laboratory studies showed elevated ferritin, triglycerides, and soluble IL-2/CD25. A cervical lymph node biopsy demonstrated an EBV-positive, reactive B-immunoblast proliferation with large atypical lymphoid cells mimicking Reed-Sternberg cells of Hodgkin lymphoma, in addition to patchy vasculitis, coagulative necrosis, and prominent hemophagocytic activity. Bilateral bone marrow biopsies showed a hypercellular marrow with patchy infiltrates of similar EBV-positive, large atypical lymphoid cells, as well as prominent hemophagocytic activity. The diagnosis of acute EBV associated lymphoproliferation with concurrent hemophagocytic lymphohistiocytosis (HLH) was rendered.Recognition of common and uncommon clinical presentations of acute EBV infection is essential, particularly when histopathologic findings raise suspicion for a possible hematolymphoid neoplasm. Both the lymph node architectural and viral cytopathic changes observed in EBV lymphadenitis exhibit significant morphologic overlap with classic Hodgkin lymphoma (cHL) and several other lymphomas, including anaplastic large cell lymphoma, diffuse large B cell lymphoma, and angioimmunoblastic T cell lymphoma. Recognition of immunohistochemical staining patterns in EBV lymphadenitis is critical to avoid misdiagnosis. Conversely, bona fide lymphoma, particularly cHL, can masquerade as EBV infection. We provide a concise discussion and tables of the histopathologic differential diagnosis of EBV lymphadenitis, including cHL and other lymphomas. Pathologists should include acute EBV infection within the differential diagnosis when confronted with clinical and pathologic findings concerning for lymphoma, particularly in adolescents and young adults.

Evolution in the definition and diagnosis of the Hodgkin lymphomas and related entities

Hodgkin lymphoma was the first of the lymphomas to be recognized as a specific disease entity. However, recent studies have highlighted the heterogeneity of the diseases associated with this eponym warranting clarification and refinement of diagnostic terminology. While classic Hodgkin lymphoma (CHL) remains an essentially unchanged diagnostic entity in the 2022 International Consensus Classification of Mature Lymphoid Neoplasms (2022 ICC), nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is now renamed nodular lymphocyte predominant B cell lymphoma (NLPBL) in recognition of the distinct pathologic, biologic, and clinical differences. Fan patterns A, B, and C (sharing the presence of evident follicular structures, and retention of a B cell rich background) will be combined in "typical" or grade 1, while the other "variant" patterns, D, E, and F, are considered grade 2. T-cell/histiocyte-rich large B cell lymphoma (THRBCL) is considered part of the "variant" NLPHL continuum.The entity previously known as "B cell lymphoma, unclassifiable (BCLU), with features intermediate between diffuse large B cell lymphoma (DLBCL) and CHL" has been renamed "mediastinal gray zone lymphoma" (MGZL) in recognition of the importance of the thymic niche in the biology of this tumor. The diagnostic criteria for MGZL have been refined and require both a high tumor cell density and a strongly preserved B cell program.This article will describe updates on CHL, NLPBL, and MGZL in the recently published 2022 ICC and provide some useful differential diagnostic clues in cases with atypical morphology or immunophenotype.

A challenging case of ALK-negative anaplastic large cell lymphoma in a 12-year-old boy: A rare case report from Syria

Introduction and importance

Anaplastic Large-cell Lymphoma (ALCL) is a rare but aggressive type of NHL that develop from mature post-thymic T-cells. ALCL constitutes approximately 2% of all lymphoid neoplasm. It is typically found among children and young adults, accounting for 10–15% of pediatric NHL, compared to 2% of adult NHL.

Case presentation

A 12-year-old Syrian boy was admitted to our hospital due to epistaxis, anorexia, weight loss and night sweats. The physical examination revealed preauricular, postauricular and submandibular lymphadenopathy. Pathological examination of the biopsy suggested Classical Hodgkin Lymphoma. Later on, Immunohistochemistry staining confirmed the diagnosis of ALK-negative Anaplastic Large Cell Lymphoma.

Clinical discussion

Systemic ALCL can be categorized into two major groups based on the expression of Anaplastic Lymphoma Kinase (ALK) protein: Systemic ALK + positive and Systemic ALK-negative. The majority of pediatric cases show an overexpression of (ALK), however, pediatric ALK-negative ALCL can occur in rare cases.

Conclusion

The aim of this article is to report a rare case of pediatric ALK-negative anaplastic large cell lymphoma that developed a rapid & aggressive growth within a few months despite the chemotherapy treatment and unfortunately led to the patient's death.

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Anaplastic large cell lymphoma (ALCL) is a rare type of non-Hodgkin lymphoma and one of the subtypes of T cell lymphoma.

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ALK-negative ALCL is rare among children and has a poor prognosis.

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Establishing ALCL diagnosis is challenging due to the similarities with CHL, DLBCL and PTCL-NOS.

Comprehensive Evaluation of the Current Knowledge on Breast Implant Associated-Anaplastic Large Cell Lymphoma

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a recently spotlighted T-cell origin non-Hodgkin's lymphoma with an increasing incidence of over 800 cases and 33 deaths reported worldwide. Development of BIA-ALCL is likely a complex process involving many factors, such as the textured implant surface, bacterial biofilm growth, immune response, and patient genetics. As the incidence of BIA-ALCL is expected to increase, it is important for all surgeons and physicians to be aware of this disease entity and acquire thorough knowledge of current evidence-based guidelines and recommendations. Early detection, accurate diagnosis, and appropriate treatment are the foundations of current care.

Anaplastic Large Cell Lymphoma, Giant Cell-Rich, Involving a Nonimplant Breast: A Case Report and Review of the Literature

Primary breast lymphomas are uncommon tumors and account for <1% of all malignant neoplasms of the breast. They are almost always of non-Hodgkin type, with B-cell lymphomas being the most common subtype. Anaplastic large cell lymphoma (ALCL) is a rare T-cell lymphoma that can involve the breast. Most of the articles in the literature describe ALCL in association with breast implants. We present a 48-year-old woman with a left breast enlargement and no history of an implant. Microscopic sections showed a high-grade CD30-positive lymphoid neoplasm with frequent giant cells, which turned out to be a primary ALCL of the breast, giant cell-rich pattern. To our knowledge, no cases of primary ALCL, giant cell-rich variant, have been reported in the breast in the absence of an implant making our case unique.

Assessment of Silicone Particle Migration Among Women Undergoing Removal or Revision of Silicone Breast Implants in the Netherlands

IMPORTANCE

Silicone breast implants have been on the market for breast augmentation or breast reconstruction for approximately 60 years but may lead to medical complications, also called breast implant illness.

OBJECTIVE

To evaluate the existence of silicone gel bleed and migration over a long time period, including the period in which the newer cohesive silicone gel breast implants were used.

DESIGN, SETTING, AND PARTICIPANTS

In this single-center case series, capsule tissue and lymph node samples were collected from women who underwent removal or revision of silicone breast implants from January 1, 1986, to August 18, 2020, and data were extracted from the pathological reports and revision of the histology if data were missing. All tissues were examined using standard light microscopy, some extended with modified oil red O staining and energy-dispersive radiographic spectroscopy. A total of 365 women had capsular tissue removed, including 15 patients who also had lymph nodes removed, and 24 women had only lymph nodes removed. Data were analyzed from January to May 2021.

EXPOSURES

Silicone breast implants.

MAIN OUTCOMES AND MEASURES

The main outcome was presence or absence of silicones inside or outside the capsule. One-way analysis of variance was used to determine significance between groups.

RESULTS

Among a total of 389 women with silicone breast implants (mean [SD] age, 50.5 [11.2] years), 384 women (98.8%) had silicone particles present in the tissues, indicating silicone gel bleed. In 337 women (86.6%), silicone particles were observed outside the capsule (ie, in tissues surrounding the capsule and/or lymph nodes), indicating silicone migration. In 47 women (12.1%), silicone particles were only present within the capsule. In 5 women (1.2%), no silicone particles were detected in the tissues. Patients were divided into 2 groups, with 46 women who received cohesive silicone gel breast implants and 343 women who received either an older or a newer type of breast implant. There were no differences in silicone gel bleed or migration between groups (silicone detected outside or inside capsule: 44 women [95.7%] vs 340 women [99.1%]; P = .19).

CONCLUSIONS AND RELEVANCE

In this case series including women with noncohesive or cohesive silicone gel breast implants, silicone leakage occurred in 98.8% of women, indicating silicone gel bleed, and in 86.6% of women, migration of silicone particles outside the capsule was detected.

Constitutive PSGL-1 Correlates with CD30 and TCR Pathways and Represents a Potential Target for Immunotherapy in Anaplastic Large T-Cell Lymphoma

Simple Summary

P-selectin glycoprotein ligand-1 (PSGL-1), coded by the SELPLG gene, is the major ligand of selectins and plays a pivotal role in tethering, rolling and extravasation of immune cells. PSGL-1 involvement in core molecular programs, such as SYK, PLCγ2, PI3Kγ or MAPK pathways, suggests additional functions beyond the modulation of cell trafficking. Recently, several studies identified a novel mechanism responsible for PSGL-1-mediated immune suppression in the tumor microenvironment and proved a novel concept of PSGL-1 as a critical checkpoint molecule for tumor immunotherapy. The immunotherapeutic approach has gained an ever-growing interest in the treatment of several hematological malignancies, and in particular, novel targets for immunotherapy are still highly sought-after in T-cell lymphomas. Based on our results obtained through gene expression profiling and immunohistochemical analysis, PSGL-1, already suggested as a potential target in multiple myeloma humoral immunotherapy, could be considered noteworthy among the candidates.

Abstract

Due to the high expression of P-selectin glycoprotein ligand-1 (PSGL-1) in lymphoproliferative disorders and in multiple myeloma, it has been considered as a potential target for humoral immunotherapy, as well as an immune checkpoint inhibitor in T-cells. By investigating the expression of SELPLG in 678 T- and B-cell samples by gene expression profiling (GEP), further supported by tissue microarray and immunohistochemical analysis, we identified anaplastic large T-cell lymphoma (ALCL) as constitutively expressing SELPLG at high levels. Moreover, GEP analysis in CD30+ ALCLs highlighted a positive correlation of SELPLG with TNFRSF8 (CD30-coding gene) and T-cell receptor (TCR)-signaling genes (LCK, LAT, SYK and JUN), suggesting that the common dysregulation of TCR expression in ALCLs may be bypassed by the involvement of PSGL-1 in T-cell activation and survival. Finally, we evaluated the effects elicited by in vitro treatment with two anti-PSGL-1 antibodies (KPL-1 and TB5) on the activation of the complement system and induction of apoptosis in human ALCL cell lines. In conclusion, our data demonstrated that PSGL-1 is specifically enriched in ALCLs, altering cell motility and viability due to its involvement in CD30 and TCR signaling, and it might be considered as a promising candidate for novel immunotherapeutic approaches in ALCLs.

Minimal Disease Monitoring in Pediatric Non-Hodgkin's Lymphoma: Current Clinical Application and Future Challenges

Minimal residual disease (MRD) detection is established routine practice for treatment stratification in leukemia and used for treatment optimization in adult lymphomas. Minimal disease studies in childhood non-Hodgkin lymphomas are challenged by stratified treatment in different subtypes, high cure rates, low patient numbers, limited initial tumor material, and early progression. Current clinical applications differ between the subtypes. A prognostic value of minimal disseminated disease (MDD) could not yet be clearly established for lymphoblastic lymphoma using flow cytometry and PCR-based methods for T-cell receptor (TCR) or immunoglobulin (IG) rearrangements. MYC-IGH fusion sequences or IG rearrangements enable minimal disease detection in Burkitt lymphoma and -leukemia. An additional prognostic value of MDD in Burkitt lymphoma and early MRD in Burkitt leukemia is implicated by single studies with risk-adapted therapy. MDD and MRD determined by PCR for ALK-fusion transcripts are independent prognostic parameters for patients with ALK-positive anaplastic large cell lymphoma (ALCL). They are introduced in routine clinical practice and used for patient stratification in clinical studies. Early MRD might serve as an endpoint for clinical trials and for guiding individual therapy. Validation of MDD and MRD as prognostic parameters is required for all subtypes but ALCL. Next-generation sequencing-based methods may provide new options and applications for minimal disease evaluation in childhood lymphomas.

ALK-transformed mature T lymphocytes restore early thymus progenitor features

Anaplastic large cell lymphoma (ALCL) is a mature T cell neoplasm that often expresses the CD4+ T cell surface marker. It usually harbors the t(2;5) (p23;q35) translocation, leading to the ectopic expression of NPM-ALK, a chimeric tyrosine kinase. We demonstrated that in vitro transduction of normal human CD4+ T lymphocytes with NPM-ALK results in their immortalization and malignant transformation. The tumor cells displayed morphological and immunophenotypical characteristics of primary patient-derived anaplastic large cell lymphomas. Cell growth, proliferation, and survival were strictly dependent on NPM-ALK activity and include activation of the key factors STAT3 and DNMT1 and expression of CD30 (the hallmark of anaplastic large-cell lymphoma). Implantation of NPM-ALK-transformed CD4+ T lymphocytes into immunodeficient mice resulted in the formation of tumors indistinguishable from patients' anaplastic large cell lymphomas. Integration of "Omic" data revealed that NPM-ALK-transformed CD4+ T lymphocytes and primary NPM-ALK+ ALCL biopsies share similarities with early T cell precursors. Of note, these NPM-ALK+ lymphoma cells overexpress stem cell regulators (OCT4, SOX2, and NANOG) and HIF2A, which is known to affect hematopoietic precursor differentiation and NPM-ALK+ cell growth. Altogether, for the first time our findings suggest that NPM-ALK could restore progenitor-like features in mature CD30+ peripheral CD4+ T cells, in keeping with a thymic progenitor-like pattern.

MDMX/MDM4 is highly expressed and contributes to cell growth and survival in anaplastic large cell lymphoma

We hypothesized that murine double minute X (MDMX), a negative p53-regulator, may be involved in dysfunctional p53-signaling in anaplastic large cell lymphoma (ALCL), anaplastic lymphoma kinase (ALK)-positive and ALK-negative, characterized frequently by non-mutated TP53 (wt-p53). By western blot analysis, MDMX was highly expressed in ALK + ALCL and expressed at variable levels in ALK- ALCL cell lines. By immunohistochemistry, high MDMX levels were observed more frequently in ALK + ALCL (36/46; 78%), compared with ALK- ALCL tumors (12/29; 41%) (p < .0018, Mann-Whitney-test). FISH analysis showed MDMX-amplification in 1 of 13 (8%) ALK- ALCL tumors, and low-level MDMX copy gains in 2 of 13 (15%) ALK- ALCL and 3 of 11 (27%) ALK + ALCL tumors. MDMX-pharmacologic inhibition or siRNA-mediated MDMX-silencing were associated with activated p53 signaling, growth inhibition and apoptotic cell death in wt-p53 ALCL cells, providing evidence that targeting MDMX may provide a new therapeutic approach for ALCL patients with wt-p53.

Preclinical Evaluation of Gilteritinib on NPM1-ALK-Driven Anaplastic Large Cell Lymphoma Cells

Anaplastic large cell lymphoma (ALCL) is an aggressive type of non-Hodgkin lymphoma. More than three-fourths of anaplastic lymphoma kinase (ALK)-positive ALCL cases express the nucleophosmin 1 (NPM1)-ALK fusion gene as a result of t(2;5) chromosomal translocation. The homodimerization of NPM1-ALK fusion protein mediates constitutive activation of the chimeric tyrosine kinase activity and downstream signaling pathways responsible for lymphoma cell proliferation and survival. Gilteritinib is a tyrosine kinase inhibitor recently approved by the FDA for the treatment of FMS-like tyrosine kinase mutation-positive acute myeloid leukemia. In this study, we demonstrate for the first time gilteritinib-mediated growth inhibitory effects on NPM1-ALK-driven ALCL cells. We utilized a total of five ALCL model cell lines, including both human and murine. Gilteritinib treatment inhibits NPM1-ALK fusion kinase phosphorylation and downstream signaling, resulting in induced apoptosis. Gilteritinib-mediated apoptosis was associated with caspase 3/9, PARP cleavage, the increased expression of proapoptotic protein BAD, and decreased expression of antiapoptotic proteins, survivin and MCL-1. We also found downregulation of fusion kinase activity resulted in decreased c-Myc protein levels. Furthermore, cell-cycle analysis indicated gilteritinib induced G₀-G₁-phase cell-cycle arrest and reduced CD30 expression. In summary, our preclinical studies explored the novel therapeutic potential of gilteritinib in the treatment of ALCL cells expressing NPM1-ALK and potentially in other ALK or ALK fusion-driven hematologic or solid malignancies. IMPLICATIONS: Our preclinical results explore the use of gilteritinib for the treatment of NPM1-ALK-driven ALCL cells and pave a path for developing future clinical trials. VISUAL OVERVIEW: http://mcr.aacrjournals.org/content/molcanres/19/5/913/F1.large.jpg.

Crizotinib Resistance Mediated by Autophagy Is Higher in the Stem-Like Cell Subset in ALK-Positive Anaplastic Large Cell Lymphoma, and This Effect Is MYC-Dependent

Previously it was shown that autophagy contributes to crizotinib resistance in ALK-positive anaplastic large cell lymphoma (ALK + ALCL). We asked if autophagy is equally important in two distinct subsets of ALK + ALCL, namely Reporter Unresponsive (RU) and Reporter Responsive (RR), of which RR cells display stem-like properties. Autophagic flux was assessed with a fluorescence tagged LC3 reporter and immunoblots to detect endogenous LC3 alongside chloroquine, an autophagy inhibitor. The stem-like RR cells displayed significantly higher autophagic response upon crizotinib treatment. Their exaggerated autophagic response is cytoprotective against crizotinib, as inhibition of autophagy using chloroquine or shRNA against BECN1 or ATG7 led to a decrease in their viability. In contrast, autophagy inhibition in RU resulted in minimal changes. Since the differential protein expression of MYC is a regulator of the RU/RR dichotomy and is higher in RR cells, we asked if MYC regulates the autophagy-mediated cytoprotective effect. Inhibition of MYC in RR cells using shRNA significantly blunted crizotinib-induced autophagic response and effectively suppressed this cytoprotective effect. In conclusion, stem-like RR cells respond with rapid and intense autophagic flux which manifests with crizotinib resistance. For the first time, we have highlighted the direct role of MYC in regulating autophagy and its associated chemoresistance phenotype in ALK + ALCL stem-like cells.

NPM-ALK: A Driver of Lymphoma Pathogenesis and a Therapeutic Target

Simple Summary

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase associated with Anaplastic Large Cell lymphoma (ALCL) through oncogenic translocations mainly NPM-ALK. Chemotherapy is effective in ALK(+) ALCL patients and induces remission rates of approximately 80%. The remaining patients do not respond to chemotherapy and some patients have drug-resistant relapses. Different classes of ALK tyrosine kinase inhibitors (TKI) are available but used exclusively for EML4-ALK (+) lung cancers. The significant toxicities of most ALK inhibitors explain the delay in their use in pediatric ALCL patients. Some ALCL patients do not respond to the first generation TKI or develop an acquired resistance. Combination therapy with ALK inhibitors in ALCL is the current challenge.

Abstract

Initially discovered in anaplastic large cell lymphoma (ALCL), the ALK anaplastic lymphoma kinase is a tyrosine kinase which is affected in lymphomas by oncogenic translocations, mainly NPM-ALK. To date, chemotherapy remains a viable option in ALCL patients with ALK translocations as it leads to remission rates of approximately 80%. However, the remaining patients do not respond to chemotherapy and some patients have drug-resistant relapses. It is therefore crucial to identify new and better treatment options. Nowadays, different classes of ALK tyrosine kinase inhibitors (TKI) are available and used exclusively for EML4-ALK (+) lung cancers. In fact, the significant toxicities of most ALK inhibitors explain the delay in their use in ALCL patients, who are predominantly children. Moreover, some ALCL patients do not respond to Crizotinib, the first generation TKI, or develop an acquired resistance months following an initial response. Combination therapy with ALK inhibitors in ALCL is the current challenge.

Combined Modality Management of Sinonasal Anaplastic Lymphoma Kinase Negative Anaplastic Large Cell Lymphoma in a Geriatric Patient-Report of a Rare Case

Sinonasal anaplastic lymphoma kinase(ALK)-negative anaplastic large cell lymphoma(ALCL) without nodal involvement is exceedingly rare and the rarity of this tumor often engenders diagnostic dilemma. It has been mostly reported in pediatric, adolescent and young adult patients, mostly of Asian origin. A 70-year-old female patient presented with a mass in the left nasal cavity causing nasal obstruction for 5 months. On clinical and radiological examination, there was a 5.7 cm mass in the left nasal cavity, completely obliterating the left ethmoid sinus. Biopsy from the nasal mass showed a poorly differentiated malignant tumour with large cells arranged in sheets. On immunohistochemistry, the tumour cells were positive for leukocyte common antigen(LCA), CD30, CD43, BCL6 and focally for CD5, TIA1, granzyme B and epithelial membrane antigen(EMA), and were negative for CD56, EBV-LMP1, CD79a, PAX5, myeloperoxidase, CD34, CD7, CD4, CD8, CD138, ALK and p63, suggestive of ALK-negative ALCL. Rest of the lymphoma work-up was essentially normal and she had stage IE disease. She was treated with prephase chemotherapy (Vincristine and Prednisolone) followed by 4 cycles of CEOP[Cyclophosphamide, Etoposide (from 2nd cycle onwards), Vincristine and Prednisolone] regimen and local radiotherapy (36 Gy/20 fractions/4 weeks) by intensity modulated radiotherapy(IMRT) technique resulting in complete clinical and radiological response. At last follow-up visit, 15 months from the initial diagnosis, she was alive and disease free. Sinonasal ALK-negative ALCL is a rare tumor which can be effectively treated with a combination of multi-agent CHOP/CHOP-like regimen and local conformal radiotherapy in geriatric patients.

Molecular profiling of Chinese systemic anaplastic large cell lymphoma patients: novel evidence of genetic heterogeneity

Background

Anaplastic large cell lymphoma (ALCL) is a rare non-Hodgkin lymphoma. A comprehensive understanding of the genetic and clinical heterogeneity of ALCL may help to improve the clinical management of patients with ALCL. However, due to the rarity of the disease, the genetic heterogeneity of ALCL has not been well elucidated. This study aimed to comprehensively elucidate the mutational landscape of tumor tissue samples from patients with systemic ALCL.

Methods

Thirty-six patients with systemic ALCL were enrolled in this retrospective study. Immunohistochemistry (IHC) was performed on tumor tissues at baseline to identify anaplastic lymphoma kinase (ALK) fusions. Capture-based targeted next-generation sequencing (NGS) with a panel spanning 112 lymphoma-related genes, including ALK rearrangements, was also performed on tumor tissue samples.

Results

A total of 102 mutations were identified in the entire cohort. Among the 36 patients included in this analysis, 14 (38.8%) were ALK positive, as determined by IHC, while NGS showed 12 patients (33.3%) to harbor ALK rearrangements. Younger patients were more likely to have ALK-positive ALCL (P=0.011). Patients with wild-type (WT) ALK were more likely to have single-nucleotide variants (SNVs) and insertions or deletions (INDELs) than patients with ALK rearrangements (P=0.027). Among the 22 patients with WT ALK, the most commonly mutated genes were TP53 (n=6, 27.3%), followed by NOTCH1 (n=5, 22.7%), KMT2D (n=3, 13.6%), KRAS (n=3, 13.6%), TET2 (n=3, 13.6%), and JAK1 (n=2, 9.1%). Mutations in PRDM1, a commonly mutated gene in ALK-negative patients, were not detected in our ALK-negative cohort. Start-loss of beta-2-microglobulin (B2M) was detected in another patient; this patient had a favorable prognosis, with an overall survival exceeding 19 months.

Conclusions

Our study revealed the unique genomic profiles of Chinese ALCL patients and represents an incremental step in deepening the understanding of the genetic heterogeneity of ALCL patients.

Etiology of Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL): Current Directions in Research

Simple Summary

The first report of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) was in 1997. Although BIA-ALCL develops around breast implants, it is considered a cancer of the immune system and not a cancer of the breast ducts or lobules. Nearly all confirmed cases to date have been associated with textured surface (versus smooth surface) breast implants. As physicians have become more aware of BIA-ALCL, so has the number of reported cases, although the number of cases remains low. In most instances, patients have an excellent prognosis following removal of the breast implant and its surrounding fibrous capsule. Many theories on factors that trigger the development of BIA-ALCL, such as the presence of bacteria, have been proposed. However, the sequence(s) of events that follow the initial triggering event(s) have not been fully determined. This article summarizes the current scientific knowledge on the development of BIA-ALCL.

Abstract

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a CD30-positive, anaplastic lymphoma kinase-negative T-cell lymphoma. Where implant history is known, all confirmed cases to date have occurred in patients with exposure to textured implants. There is a spectrum of disease presentation, with the most common occurring as a seroma with an indolent course. A less common presentation occurs as locally advanced or, rarely, as metastatic disease. Here we review the immunological characteristics of BIA-ALCL and potential triggers leading to its development. BIA-ALCL occurs in an inflammatory microenvironment with significant lymphocyte and plasma cell infiltration and a prominent Th1/Th17 phenotype in advanced disease. Genetic lesions affecting the JAK/STAT signaling pathway are commonly present. Proposed triggers for the development of malignancy include mechanical friction, silicone implant shell particulates, silicone leachables, and bacteria. Of these, the bacterial hypothesis has received significant attention, supported by a plausible biologic model. In this model, bacteria form an adherent biofilm in the favorable environment of the textured implant surface, producing a bacterial load that elicits a chronic inflammatory response. Bacterial antigens, primarily of Gram-negative origin, may trigger innate immunity and induce T-cell proliferation with subsequent malignant transformation in genetically susceptible individuals. Although much remains to be elucidated regarding the multifactorial origins of BIA-ALCL, future research should focus on prevention and treatment strategies, recognizing susceptible populations, and whether decreasing the risk of BIA-ALCL is possible.

Molecular insights into pathogenesis and targeted therapy of peripheral T cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are biologically and clinically heterogeneous diseases almost all of which are associated with poor outcomes. Recent advances in gene expression profiling that helps in diagnosis and prognostication of different subtypes and next-generation sequencing have given new insights into the pathogenesis and molecular pathway of PTCL. Here, we focus on a broader description of mutational insights into the common subtypes of PTCL including PTCL not other specified type, angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma, and extra-nodal NK/T cell lymphoma, nasal type, and also present an overview of new targeted therapies currently in various stages of clinical trials.

Clinical, Histologic, and Molecular Characteristics of Anaplastic Lymphoma Kinase-positive Primary Cutaneous Anaplastic Large Cell Lymphoma

Unlike systemic anaplastic large cell lymphoma, the vast majority of primary cutaneous anaplastic large cell lymphomas (C-ALCL) do not carry translocations involving the ALK gene and do not express ALK. Expression of ALK protein therefore strongly suggests secondary cutaneous involvement of a systemic anaplastic large cell lymphoma. Recent studies described a small subgroup of ALK-positive C-ALCL, but information on frequency, prognosis, and translocation partners is virtually lacking. A total of 6/309 (2%) C-ALCL patients included in the Dutch registry for cutaneous lymphomas between 1993 and 2019 showed immunohistochemical ALK expression. Clinical and histopathologic characteristics, immunophenotype and disease course were evaluated. Underlying ALK translocations were analyzed with anchored multiplex polymerase chain reaction-based targeted next-generation sequencing. Median age at diagnosis was 39 years (range: 16 to 53 y). All patients presented with a solitary lesion. Treatment with radiotherapy (n=5) or anthracycline-based chemotherapy (n=1) resulted in complete responses in all 6 patients. Three patients developed a relapse, of whom 2 extracutaneous. After a median follow-up of 41 months, 5 patients were alive without disease and 1 patient died of lymphoma. Immunohistochemically, 3 cases (50%) showed combined nuclear and cytoplasmic ALK expression with underlying NPM1-ALK fusions, while 3 cases (50%) showed solely cytoplasmic ALK expression with variant ALK fusion partners (TRAF1, ATIC, TPM3). ALK-positive C-ALCL is extremely uncommon, has a comparable favorable prognosis to ALK-negative C-ALCL, and should be treated in the same way with radiotherapy as first-line treatment.

Identification of the Wallenda JNKKK as an Alk suppressor reveals increased competitiveness of Alk-expressing cells

Anaplastic lymphoma kinase (Alk) is a receptor tyrosine kinase of the insulin receptor super-family that functions as oncogenic driver in a range of human cancers such as neuroblastoma. In order to investigate mechanisms underlying Alk oncogenic signaling, we conducted a genetic suppressor screen in Drosophila melanogaster. Our screen identified multiple loci important for Alk signaling, including members of Ras/Raf/ERK-, Pi3K-, and STAT-pathways as well as tailless (tll) and foxo whose orthologues NR2E1/TLX and FOXO3 are transcription factors implicated in human neuroblastoma. Many of the identified suppressors were also able to modulate signaling output from activated oncogenic variants of human ALK, suggesting that our screen identified targets likely relevant in a wide range of contexts. Interestingly, two misexpression alleles of wallenda (wnd, encoding a leucine zipper bearing kinase similar to human DLK and LZK) were among the strongest suppressors. We show that Alk expression leads to a growth advantage and induces cell death in surrounding cells. Our results suggest that Alk activity conveys a competitive advantage to cells, which can be reversed by over-expression of the JNK kinase kinase Wnd.

[Clinical characteristics and prognostic factors of 40 cases of primary systemic anaplastic large cell lymphoma]

目的

分析原发系统型间变性大细胞淋巴瘤（ALCL）的临床特征及预后因素。

方法

回顾性分析2013年1月至2018年12月期间在浙江大学医学院附属第一医院住院治疗的40例ALCL患者的临床资料，总结其临床特征并分析其预后相关因素。

结果

①40例患者中男29例，女11例，中位年龄41（14～67）岁，Ann Arbor分期Ⅲ～Ⅳ期36例（90.0％），IPI评分中高危、高危23例（57.5％）；25例（62.5％）有B症状，发热最为常见，其次为消瘦、盗汗；38例（95.0％）有结外侵犯；25例（62.5％）LDH升高；25例（62.5％）Ki-67≥80％；ALK阳性22例（55.0％），中位年龄29（14～67）岁，ALK阴性18例（45.0％），中位年龄51.5（19～67）岁，年龄差异有统计学意义（P＝0.003）。②40例患者均接受化疗，采用CHOP（环磷酰胺+多柔比星+长春地辛+泼尼松）方案18例，ECHOP（依托泊苷+CHOP）方案12例，其他方案10例；26例（65.0％）获得完全缓解（CR），ALK阴性（P＝0.029，OR＝13.458）和Ki-67≥80％（P＝0.04，OR＝14.453）是CR的独立影响因素，ECHOP方案的CR率高于CHOP方案［83.3％（10/12）对38.9％（7/18），P＝0.026］。③LDH水平、IPI评分、ALK表达情况以及化疗方案的选择对无进展生存（PFS）和总生存（OS）影响有统计学意义（P<0.05）。

结论

ALCL发病男性居多，青少年至中老年均有发病，ALK阳性中年轻患者居多，诊断时临床分期晚，多数患者有结外侵犯，半数以上患者有B症状、LDH升高、Ki-67高表达；ALK表达与否、Ki-67表达水平以及化疗方案的选择可影响疗效，LDH水平、IPI评分、ALK表达与否以及化疗方案的选择可影响PFS和OS；ECHOP是较优的化疗方案，可改善预后。

Intrasinusoidal HHV8-EBV-Positive Large B-Cell Lymphoma With Features of Germinotropic Lymphoproliferative Disorder

Germinotropic lymphoproliferative disorder (GLPD) is a poorly characterized lymphoproliferative entity, recently included in the World Health Organization classification of hematolymphoid neoplasms. The histological pattern of this disease comprises monotypic plasmablasts that involve the germinal centers of the lymphoid follicles (germinotrophism), forming confluent aggregates positive for both human herpes virus type 8 (HHV8) and Epstein-Barr virus. Currently, after 17 years of its first description, only 18 cases have been reported. In this article, we describe a case of a GLPD presenting in an immunocompetent 79-year-old woman with localized axillary lymphadenopathy, showing a prominent sinusoidal growth pattern, with no evidence of germinotrophism or extrasinusoidal spread. Stinking pleomorphism in tumor cells was also noted. An extension study has not revealed involvement of other groups of lymph nodes or extralymphoid sites. The patient is alive and has shown no relapse after 8 years follow-up (the longest follow-up reported period for this entity). This previously unrecognized pure sinusoidal growth pattern along with the striking pleomorphism in neoplastic cells closely mimics the appearance of an anaplastic large cell lymphoma. GLPD is not usually considered in such a setting, but it should be included in the differential diagnosis of sinusoidal proliferations. Our findings contribute to the expansion of the morphological spectrum of HHV8-associated lymphoproliferative lesions and aids in the characterization of the very infrequent GLPD entity.

Existence of reprogrammed lymphoma stem cells in a murine ALCL-like model

While cancer stem cells are well established in certain hematologic and solid malignancies, their existence in T cell lymphoma is unclear and the origin of disease is not fully understood. To examine the existence of lymphoma stem cells, we utilized a mouse model of anaplastic large cell lymphoma. Established NPM-ALK⁺ lymphomas contained heterogeneous cell populations ranging from mature T cells to undifferentiated hematopoietic stem cells. Interestingly, CD4^-/CD8^- double negative (DN) lymphoma cells aberrantly expressed the T cell receptor α/β chain. Serial transplantation of sorted CD4/CD8 and DN lymphoma subpopulations identified lymphoma stem cells within the DN3/DN4 T cell population, whereas all other subpopulations failed to establish serial lymphomas. Moreover, transplanted lymphoma DN3/DN4 T cells were able to differentiate and gave rise to mature lymphoma T cells. Gene expression analyses unmasked stem-cell-like transcriptional regulation of the identified lymphoma stem cell population. Furthermore, these lymphoma stem cells are characterized by low CD30 expression levels, which might contribute to limited long-term therapeutic success in patients treated with anti-CD30-targeted therapies. In summary, our results highlight the existence of a lymphoma stem cell population in a NPM-ALK-driven CD30⁺ mouse model, thereby giving the opportunity to test innovative treatment strategies developed to eradicate the origin of disease.

STAT3 Mutation Is Associated with STAT3 Activation in CD30+ ALK- ALCL

Peripheral T-cell lymphomas (PTCL) are a heterogeneous, and often aggressive group of non-Hodgkin lymphomas. Recent advances in the molecular and genetic characterization of PTCLs have helped to delineate differences and similarities between the various subtypes, and the JAK/STAT pathway has been found to play an important oncogenic role. Here, we aimed to characterize the JAK/STAT pathway in PTCL subtypes and investigate whether the activation of the pathway correlates with the frequency of STAT gene mutations. Patient samples from AITL (n = 30), ALCL (n = 21) and PTCL-NOS (n = 12) cases were sequenced for STAT3, STAT5B, JAK1, JAK3, and RHOA mutations using amplicon sequencing and stained immunohistochemically for pSTAT3, pMAPK, and pAKT. We discovered STAT3 mutations in 13% of AITL, 13% of ALK⁺ ALCL, 38% of ALK⁻ ALCL and 17% of PTCL-NOS cases. However, no STAT5B mutations were found and JAK mutations were only present in ALK^- ALCL (15%). Concurrent mutations were found in all subgroups except ALK⁺ ALCL where STAT3 mutations were always seen alone. High pY-STAT3 expression was observed especially in AITL and ALCL samples. When studying JAK-STAT pathway mutations, pY-STAT3 expression was highest in PTCLs harboring either JAK1 or STAT3 mutations and CD30⁺ phenotype representing primarily ALK⁻ ALCLs. Further investigation is needed to elucidate the molecular mechanisms of JAK-STAT pathway activation in PTCL.

Gluteal Implant-Associated Anaplastic Large Cell Lymphoma

The association of anaplastic large cell lymphoma (ALCL) to breast implants (breast implant-associated ALCL) has brought back the discussion on the clinical safety of the use of silicone implants. A 63-year-old woman came to our institution in early 2015, reporting a gluteal augmentation with silicone implants in 2006 and a recent increasing volume and distortion of the left buttock. Radiologic imaging showed a large amount of fluid collection around the implant. The left side implant was removed and the capsule was left intact, presupposing a future reimplantation. The fluid collected was positive for Staphylococcus aureus. Three years later, she presented again with a new seroma on the explanted side and was submitted to total capsulectomy and fluid drainage, and the material was submitted to laboratory examination. Culture results were negative. Pathologic preparation and sections of the capsule and lumps showed large cells characterized by horseshoe-shaped nuclei. Immunohistochemistry was positive for CD30/CD4 and negative for anaplastic lymphoma kinase, confirming the presence of ALCL, then associated with gluteal implant, an event not described in literature. Positron emission tomography/computed tomography and bone marrow biopsy were performed, and neither showed any other sites involved. The same disease in a new location introduces important discussions about the understanding of this abnormality and poses certain risks and safety issues to clinical scenarios to be discussed. Regardless of whether it is a breast implant-associated ALCL or a gluteal implant-associated ALCL, now we are probably facing an implant augmentation-associated disease and a new international alert should be addressed to the scientific community. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, V.

Brentuximab vedotin in the treatment of CD30+ PTCL

In this timely Blood Spotlight, Barta et al summarize for the practicing hematologist the strengths and limitations of current data on brentuximab vedotin–based treatment in peripheral T-cell lymphoma (PTCL).

Anaplastic lymphoma kinase-negative anaplastic large cell lymphoma masquerading as Behcet's disease: A case report and review of literature

BACKGROUND

Anaplastic large cell lymphoma (ALCL) is a CD30-positive T cell lymphoma, a rare type of non-Hodgkin lymphoma. The current World Health Organization classification system divides ALCLs into anaplastic lymphoma kinase (ALK)-positive and ALK-negative groups. ALCL rarely presents in the gastrointestinal tract.

CASE SUMMARY

A 54-year-old male was admitted to the department of gastroenterology for abdominal pain. He presented with lower abdominal pain, diarrhea and recurrent oral and penile ulcers. He was misdiagnosed with Behcet's disease and treated with prednisone. But after one month, he was hospitalized in another hospital for reexamination. This time, the lesion on the penis was biopsied for histological examination. The final pathological diagnosis was ALCL, ALK-negative. The patient was treated with cyclophosphamide, doxorubicin, vincristine, prednisolone chemotherapy. However, he died within one month.

CONCLUSION

Gastrointestinal ALCL needs to be considered in the differential diagnosis to avoid delaying treatment. Repeated biopsy is the most important for early diagnosis and treatment.

Lymphomatoid papulosis: an update and review

Lymphomatoid papulosis (LyP) is a benign chronic often relapsing skin condition that belongs to the CD30-positive cutaneous lymphoproliferative disorders. LyP typically presents as crops of lesions with a tendency to self-resolve, and morphology can range from solitary to agminated or diffuse papules and plaques to nodules or tumours. The clinical-histological spectrum can range from borderline cases to overlap with primary cutaneous anaplastic cell lymphoma (pcALCL). Histology and immunophenotype commonly show overlap with other CD30-positive disorders and sometimes may be identical to pcALCL, making its diagnosis more difficult. Patients with LyP have an increased risk of developing a second neoplasm such as mycosis fungoides, pcALCL and/or Hodgkin lymphoma. Clinical correlation allows its proper classification and diagnosis, which is fundamental for treatment and prognosis. This review focuses on the clinical appearance, histopathological features, diagnosis, differential diagnosis and management of LyP.

Cell of Origin and Immunologic Events in the Pathogenesis of Breast Implant-Associated Anaplastic Large-Cell Lymphoma

Breast implant–associated anaplastic large-cell lymphoma (BIA-ALCL) is a CD30-positive, anaplastic lymphoma kinase–negative T-cell lymphoma. Nearly all cases have been associated with textured implants. Most cases are of effusion-limited, indolent disease, with an excellent prognosis after implant and capsule removal. However, capsular invasion and tumor mass have a more aggressive course and a fatal outcome risk. This review summarizes the current knowledge on BIA-ALCL cell of origin and immunologic factors underlying its pathogenesis. Cytokine expression profiling of BIA-ALCL cell lines and clinical specimens reveals a predominantly type 17 helper T-cell (Th17)/Th1 signature, implicating this as its cell of origin. However, a Th2 allergic inflammatory response is suggested by the presence of IL-13, with infiltration of eosinophils and IgE-coated mast cells in clinical specimens of BIA-ALCL. The microenvironment-induced T-cell plasticity, a factor increasingly appreciated, may partially explain these divergent results. Mutations resulting in constitutive Janus kinase (JAK)–STAT activation have been detected and associated with BIA-ALCL pathogenesis in a small number of cases. One possible scenario is that an inflammatory microenvironment stimulates an immune response, followed by polyclonal expansion of Th17/Th1 cell subsets with release of inflammatory cytokines and chemokines and accumulation of seroma. JAK-STAT3 gain-of-function mutations within this pathway and others may subsequently lead to monoclonal T-cell proliferation and clinical BIA-ALCL. Current research suggests that therapies targeting JAK proteins warrant investigation in BIA-ALCL.

Migration Properties Distinguish Tumor Cells of Classical Hodgkin Lymphoma from Anaplastic Large Cell Lymphoma Cells

Anaplastic large cell lymphoma (ALCL) and classical Hodgkin lymphoma (cHL) are lymphomas that contain CD30-expressing tumor cells and have numerous pathological similarities. Whereas ALCL is usually diagnosed at an advanced stage, cHL more frequently presents with localized disease. The aim of the present study was to elucidate the mechanisms underlying the different clinical presentation of ALCL and cHL. Chemokine and chemokine receptor expression were similar in primary ALCL and cHL cases apart from the known overexpression of the chemokines CCL17 and CCL22 in the Hodgkin and Reed-Sternberg (HRS) cells of cHL. Consistent with the overexpression of these chemokines, primary cHL cases encountered a significantly denser T cell microenvironment than ALCL. Additionally to differences in the interaction with their microenvironment, cHL cell lines presented a lower and less efficient intrinsic cell motility than ALCL cell lines, as assessed by time-lapse microscopy in a collagen gel and transwell migration assays. We thus propose that the combination of impaired basal cell motility and differences in the interaction with the microenvironment hamper the dissemination of HRS cells in cHL when compared with the tumor cells of ALCL.

Genomics of LGL leukemia and select other rare leukemia/lymphomas

Genomic analysis of cancer offers the hope of identifying new treatments or aiding in the selection of existing treatments. Rare leukemias pose additional challenges in this regard as samples may be hard to acquire and when found the underlying pathway may not be attractive to drug development since so few individuals are affected. In this case, it can be useful to identify common mutational overlap among subsets of rare leukemias to increase the number of individuals that may benefit from a targeted therapy. This chapter examines the current mutational landscape of large granular lymphocyte (LGL) leukemia with a focus on STAT3 mutations, the most common mutation in LGL leukemia to date. We examined the linkage between these mutations and autoimmune symptoms and disorders, in cases of obvious and suspected LGL leukemia. We then summarized and compared mutations in a set of other rare leukemias that also have JAK/STAT signaling pathway activation brought about by genomic changes. These include T-cell acute lymphoblastic leukemia (T-ALL), T-cell prolymphocytic leukemia (T-PLL), cutaneous T-cell lymphoma (CTCL), select peripheral T-cell lymphoma (PTCL), and adult T-cell leukemia/lymphoma (ATLL). Though STAT3 activation is common in these leukemias, the way in which it is achieved, such as the activating cytokine pathway and/or the co-mutational background, is quite diverse.

Breast implant-associated anaplastic large cell lymphoma, an under-recognised entity

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a rare form of T-cell lymphoma, recently linked to the use of certain types of breast implants. Although rare, BIA-ALCL is being increasingly recognised and radiologists can play an important role in its early diagnosis. BIA-ALCL is thought to be related to chronic inflammation from indolent infection of the biofilm surrounding implants leading to malignant transformation of activated T cells in genetically susceptible individuals. Clinical features include breast enlargement or asymmetry, discomfort, heaviness and/or a palpable mass in the context of long-standing implant(s). Ultrasound is the primary imaging modality, and the presence of more than a trace of peri-implant fluid should prompt consideration of aspiration for cytology, flow cytometry and microbiological analysis. This article reviews the clinical, imaging and pathology features of BIA-ALCL. In addition, the current recommended management guidelines for suspected cases are discussed.

A Review on a Deep Learning Perspective in Brain Cancer Classification

A World Health Organization (WHO) Feb 2018 report has recently shown that mortality rate due to brain or central nervous system (CNS) cancer is the highest in the Asian continent. It is of critical importance that cancer be detected earlier so that many of these lives can be saved. Cancer grading is an important aspect for targeted therapy. As cancer diagnosis is highly invasive, time consuming and expensive, there is an immediate requirement to develop a non-invasive, cost-effective and efficient tools for brain cancer characterization and grade estimation. Brain scans using magnetic resonance imaging (MRI), computed tomography (CT), as well as other imaging modalities, are fast and safer methods for tumor detection. In this paper, we tried to summarize the pathophysiology of brain cancer, imaging modalities of brain cancer and automatic computer assisted methods for brain cancer characterization in a machine and deep learning paradigm. Another objective of this paper is to find the current issues in existing engineering methods and also project a future paradigm. Further, we have highlighted the relationship between brain cancer and other brain disorders like stroke, Alzheimer’s, Parkinson’s, and Wilson’s disease, leukoriaosis, and other neurological disorders in the context of machine learning and the deep learning paradigm.

Pearls and pitfalls in the diagnostic workup of small lymph node biopsies

All pathology subspecialties are more frequently receiving small needle core biopsies for the diagnosis of new lesions. While this results in potential diagnostic pitfalls, the tools available for hematopathology, including extensive panels of immunostains, PRC-based clonality assessment, and flow cytometry often allow accurate diagnoses even with very small specimens. This review presents a brief approach to such biopsies, using morphologic cues as well as ancillary studies, which provides an experience-based framework for approaching these cases and coming to a clear diagnosis while avoiding diagnostic errors. The approach is divided into three parts based on H & E cell morphology.