Diagnostic and prognostic evaluation of phenotypic markers TRAF1, MUM1, BCL2 and CD15 in cutaneous CD30-positive lymphoproliferative disorders

Primary cutaneous T-cell lymphoma: a review of the most common entities with focus on recent updates

Cutaneous T-cell lymphomas are an heterogeneous group of uncommon lymphoid neoplasms that are challenging to diagnose and require close collaboration between dermatologists, pathologists and hematologists/oncologists. This article reviews the most common cutaneous T-cell lymphomas: mycosis fungoides (both classic and variant forms) as well as its leukemic counterpart Sézary syndrome, CD30+ T-cell lymphoproliferative disorders including the ever-expanding group of lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma, and primary cutaneous CD4+ small/medium lymphoproliferative disorder. We discuss the classic clinical and histopathologic features of these lymphomas and review how they can be distinguished from reactive entities. In particularly, updates to these diagnostic categories and current controversies in classification are highlighted. Moreover, we review the prognosis and treatment for each entity. These lymphomas exhibit variable prognosis, and therefore it is important to correctly classify atypical cutaneous T-cell infiltrates for appropriate patient treatment and prognosis. Cutaneous T-cell lymphomas are at the interface of several medical specialties; this review seeks to summarize key features of these lymphomas and highlight new and emerging insights into these lymphomas.

Primary cutaneous T-cell lymphoma: a review of the most common entities with focus on recent updates

Cutaneous T-cell lymphomas are an heterogeneous group of uncommon lymphoid neoplasms that are challenging to diagnose and require close collaboration between dermatologists, pathologists and hematologists/oncologists. This article reviews the most common cutaneous T-cell lymphomas: mycosis fungoides (both classic and variant forms) as well as its leukemic counterpart Sézary syndrome, CD30+ T-cell lymphoproliferative disorders including the ever-expanding group of lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma, and primary cutaneous CD4+ small/medium lymphoproliferative disorder. We discuss the classic clinical and histopathologic features of these lymphomas and review how they can be distinguished from reactive entities. In particularly, updates to these diagnostic categories and current controversies in classification are highlighted. Moreover, we review the prognosis and treatment for each entity. These lymphomas exhibit variable prognosis, and therefore it is important to correctly classify atypical cutaneous T-cell infiltrates for appropriate patient treatment and prognosis. Cutaneous T-cell lymphomas are at the interface of several medical specialties; this review seeks to summarize key features of these lymphomas and highlight new and emerging insights into these lymphomas.

Transdifferentiation, phenotypic infidelity, progression, and transformation in T/NK-cell neoplasms: Report from the 2021 SH/EAHP Workshop

OBJECTIVES

Sessions 8 and 9 of the 2021 Society for Hematopathology and the European Association for Haematopathology Workshop aimed to collect examples of transdifferentiation, lineage infidelity, progression, and transformation in precursor and mature T/natural killer (NK)-cell neoplasms.

METHODS

Twenty-eight cases were submitted and analyzed, with whole-exome sequencing and genome-wide RNA expression analysis performed in a subset of the cases.

RESULTS

In session 8, 7 T-lymphoblastic lymphoma/leukemia cases were received that showed transdifferentiation to clonally related mature myeloid hematopoietic neoplasms, including 6 histiocytic/dendritic cell lineage neoplasms and a mast cell sarcoma. Session 9 included 21 mature T-cell neoplasms that were grouped into 3 themes. The first one addressed phenotypic infidelity in mature T-cell lymphomas (TCLs) and included 8 TCLs expressing aberrant antigens, mimicking classic Hodgkin and non-Hodgkin B-cell lymphomas. The second theme addressed disease progression in TCL and included 5 cutaneous T-cell lymphoproliferative disorders and 2 T-cell large granular lymphocyte proliferations with subsequent progression to systemic TCL. The third theme included 6 patients with TCL with T-follicular helper phenotype, mainly angioimmunoblastic T-cell lymphoma, with concurrent/subsequent clonal hematopoiesis or myeloid neoplasms and/or subsequent/concomitant diffuse large B-cell lymphoma.

CONCLUSIONS

This cohort of cases allowed us to illustrate, discuss, and review current concepts of transdifferentiation, aberrant antigen expression, and progression in various T/NK-cell neoplasms.

Secondary skin involvement in classic Hodgkin lymphoma: Results of an international collaborative cutaneous lymphoma working group study of 25 patients

BACKGROUND

Cutaneous involvement by classic Hodgkin lymphoma (CHL) is an extraordinarily rare phenomenon in the current era. To date, no single large case series of cutaneous involvement by Hodgkin lymphoma has ever been reported in the literature.

METHODS

A comprehensive search for cases designated "skin" and "Hodgkin" was performed at different institutions between 1990 and 2020. Twenty-five cases were identified, and each case was independently reviewed by at least three board-certified dermatopathologists and/or hematopathologists.

RESULTS

All cases represented examples of systemic CHL with secondary skin dissemination. A single lesion, usually a tumor, nodule or infiltrative plaque was observed in 56% of cases and multiple lesions were present in 28% of cases. Most patients (86%-12/14) had a diagnosis of stage IV disease at first diagnosis. The interval between the clinical (first) diagnosis of HL and the development of skin lesions ranged between 6 and 108 months (average 33.75 months). Comprehensive histopathologic evaluation of these cases (at the initial diagnosis) revealed a diagnosis of classic HL not otherwise specified (NOS) in 60% of cases (15/25), nodular sclerosis type in 24% (6/25), mixed cellularity in 12% (3/25), and lymphocyte depleted in 4% (1/25).

CONCLUSIONS

We provide documentation of a large series of CHL with secondary skin involvement in association with CHL with additional clinical, morphologic, and immunophenotypic features.

Enhanced PD-L1 expression on tumor cells in primary cutaneous large T-cell lymphoma with CD30 expression as classic Hodgkin lymphoma mimics: A report of lymph node lesions of two cases

Neoplastic PD-L1 (nPD-L1, clone SP142) expression remains unclear in cutaneous T-cell lymphoma (CTCL), although it is well-documented in classic Hodgkin lymphoma (CHL). Here, we report two cases of primary cutaneous large T-cell lymphoma (PCLTCL) with CD30 expression that developed secondary nodal lesions morphologically mimicking CHL, and describe their PD-L1 expression. Our two cases (52- and 60-year-old males) had long-standing clinical courses of CTCL. Their PCLTCL with CD30 expression developed nodal lesions, having a nodular growth pattern containing scattered CD30+ Hodgkin and Reed-Sternberg-like and/or lacunar cells that expressed CD15 but did not harbor Epstein-Barr virus. Their differential diagnosis from CHL was challenging. A diagnosis of PCLTCL with secondary nodal involvement featuring CHL mimicry was based on comparison of the primary and secondary lesions. In one case, shared expression of the same T-cell antigen was revealed by immunohistochemistry, and in the other, identical clonal TCR rearrangement was demonstrated by polymerase chain reaction (PCR). Interestingly, nPD-L1 was expressed on more than 50% of the tumor cells in the secondary nodal lesions, but on very few in the primary cutaneous lesions, in both cases. This is the first report of nPD-L1 expression greatly increasing with PCLTCL tumor progression to nodal involvement.

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.

CD30-positive primary cutaneous lymphoproliferative disorders: molecular alterations and targeted therapies

Primary cutaneous CD30-positive T-cell lymphoproliferative disorders are the second most common subgroup of cutaneous T-cell lymphomas. They include two clinically different entities with some overlapping features and borderline cases: lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma. Molecular studies of primary cutaneous anaplastic large cell lymphoma reveal an increasing level of heterogeneity that is associated with histological and immunophenotypic features of the cases and their response to specific therapies. Here, we review the most significant genetic, epigenetic and molecular alterations described to date in primary cutaneous CD30-positive T-cell lymphoproliferative disorders, and their potential as therapeutic targets.

CD30-Positive Lymphoproliferative Disorders

Primary cutaneous CD30-positive lymphoproliferative disorders (CD30+ LPD) encompass lymphomatoid papulosis (LyP), primary cutaneous anaplastic large cell lymphoma (pcALCL), and borderline lesions [1]. CD30+ LPD are the second most common cutaneous T-cell lymphomas (CTCL) after mycosis fungoides (MF) and represent approximately 25% of all CTCL cases [2]. Their common phenotypic hallmark is an expression of the CD30 antigen, a cytokine receptor belonging to the tumor necrosis factor (TNF) receptor superfamily. Both LyP and pcALCL show numerous clinical, histological and immunophenotypic variants, and generally have an indolent course with a favorable prognosis. Overlapping features of LyP and pcALCL with other CD30+ T-cell lymphomas, inflammatory, and/or infectious conditions emphasize the importance of careful clinicopathologic correlation and staging.

Nodal Involvement by CD30+ Cutaneous Lymphoproliferative Disorders and Its Challenging Differentiation From Classical Hodgkin Lymphoma

Primary cutaneous lymphomas are defined as non-Hodgkin lymphomas that present in the skin with no evidence of extracutaneous disease at the time of diagnosis. Mycosis fungoides is the most common type of primary cutaneous T-cell lymphoma, representing almost 50% of primary cutaneous T-cell lymphomas, and primary cutaneous CD30+ T-cell lymphoproliferative disorders are the second most common group (30%). Transformed mycosis fungoides is usually CD30+ and can involve multiple nodal sites; other primary cutaneous CD30+ T-cell lymphoproliferative disorders can also involve draining regional nodes. Nodal involvement by CD30+ T-cell lymphoproliferative disorders can mimic classical Hodgkin lymphoma, which can aberrantly express T-cell antigens. The aim of this article is to briefly review salient clinical, histologic, immunophenotypic, and molecular features that can be used to distinguish lymph node involvement by CD30+ cutaneous T-cell lymphomas and lymphoproliferative disorders from classical Hodgkin lymphoma, a clinically important differential diagnosis that represents a challenging task for the pathologist.

Analysis of CD15, CD57 and HIF-1α in biopsies of patients with peri-implantitis

Peri-implantitis is an infectious disease characterized by inflammation of the tissues surrounding the implant, bleeding on probing with or without suppuration, and bone loss. Peri-implant lesions contain a leukocyte infiltrate of plasma cells, lymphocytes, macrophages and neutrophils. A survey of the literature did not show any studies reporting an association between hypoxia and peri-implantitis. The aim of the present cross-sectional study was to evaluate histological changes and immunostaining for CD15, CD57 and HIF-1α in the peri-implant mucosa of patients with and without peri-implantitis. Mucosal biopsies were obtained from 18 patients with peri-implantitis and 10 control subjects without peri-implantitis at a private health care center between 2010 and 2012. The sections were fixed in 10% buffered formalin, processed and embedded in paraffin for histopathological and immunohistochemical study. Acanthosis, spongiosis and exocytosis were observed in both groups, with no significant difference between them. The peri-implantitis group showed increased immunostaining for CD15, a neutrophil marker, and HIF-1α, a tissue hypoxia marker, but no significant difference in immunostaining for CD57, a Natural Killer cell marker. The increase in neutrophil (CD15) and hypoxia (HIF-1α) markers in patients with peri-implantitis suggests an active participation of neutrophils and hypoxia in the pathogenesis of this disease. Since the present study was the first to evaluate the expression of CD15, CD57 and HIF-1α in peri-implant tissues, further studies should be performed to better understand the role of these molecules in peri-implantitis.

Effectiveness of low-dose radiation for primary cutaneous anaplastic large cell lymphoma

Primary cutaneous anaplastic large cell lymphoma (pcALCL) is conventionally treated with radiation therapy (RT) doses ≥30 Gy. In a series of 21 patients with pcALCL, responses were examined after a range of RT doses: ≤20 Gy, 20 to 29 Gy, and ≥30 Gy. Three-year freedom from local relapse was 100%, 86%, and 100%, respectively (P = .28). Low-dose RT appeared to be an acceptable approach for local control in the setting of the indolent, chronic course of pcALCL in this series.

Purpose

Primary cutaneous anaplastic large cell lymphoma (pcALCL) is conventionally treated with radiation therapy (RT) doses ≥30 GGy, but effectiveness of lower doses is unclear. We compared responses after a range of RT doses for pcALCL.

Methods and materials

From 1999 through 2015, 45 lesions in 21 patients met clinicopathologic pcALCL diagnostic criteria and were treated with RT (<20 Gy, 20-29 Gy, or ≥30 Gy dose). Complete clinical (CR) and partial responses (PR) were compared by dose using Fisher exact test. Progression-free and overall survivals were calculated using the Kaplan-Meier method.

Results

Forty-two percent of lesions were treated with <20 Gy, 22% with 20 to 29 Gy, and 35% with ≥30 Gy. Within 12 weeks, 100% responded, with 67% CR and 33% PR; by last follow-up, 87% achieved CR and 13% PR (no difference by RT dose; P = .84). Three-year freedom from local relapse was 100%, 86%, and 100% with <20 Gy, 20 to 29 Gy, and ≥30 Gy, respectively (P = .28). Many patients ultimately demonstrated other cutaneous or systemic relapse, with 55% 3-year and 29% 10-year progression-free survival. Overall survival at 10 years was 59%, with 2 deaths from complications of disease.

Conclusions

Low-dose RT offered excellent local control in the setting of the indolent, chronic course of pcALCL in this patient cohort.

THZ1 targeting CDK7 suppresses STAT transcriptional activity and sensitizes T-cell lymphomas to BCL2 inhibitors

Peripheral T-cell lymphomas (PTCL) are aggressive diseases with poor response to chemotherapy and dismal survival. Identification of effective strategies to target PTCL biology represents an urgent need. Here we report that PTCL are sensitive to transcription-targeting drugs, and, in particular, to THZ1, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7). The STAT-signalling pathway is highly vulnerable to THZ1 even in PTCL cells that carry the activating STAT3 mutation Y640F. In mutant cells, CDK7 inhibition decreases STAT3 chromatin binding and expression of highly transcribed target genes like MYC, PIM1, MCL1, CD30, IL2RA, CDC25A and IL4R. In surviving cells, THZ1 decreases the expression of STAT-regulated anti-apoptotic BH3 family members MCL1 and BCL-XL sensitizing PTCL cells to BH3 mimetic drugs. Accordingly, the combination of THZ1 and the BH3 mimetic obatoclax improves lymphoma growth control in a primary PTCL ex vivo culture and in two STAT3-mutant PTCL xenografts, delineating a potential targeted agent-based therapeutic option for these patients.

T-cell lymphomas are aggressive diseases associated with poor outcome. Here, the authors show that the THZ1, a CDK7 inhibitor, suppresses STAT transcriptional activity leading to apoptosis and sensitization to BCL2 inhibitors in T-cell lymphomas.

Radiation Therapy for Primary Cutaneous Anaplastic Large Cell Lymphoma: An International Lymphoma Radiation Oncology Group Multi-institutional Experience

PURPOSE

To collect response rates of primary cutaneous anaplastic large cell lymphoma, a rare cutaneous T-cell lymphoma, to radiation therapy (RT), and to determine potential prognostic factors predictive of outcome.

METHODS AND MATERIALS

The study was a retrospective analysis of patients with primary cutaneous anaplastic large cell lymphoma who received RT as primary therapy or after surgical excision. Data collected include initial stage of disease, RT modality (electron/photon), total dose, fractionation, response to treatment, and local recurrence. Radiation therapy was delivered at 8 participating International Lymphoma Radiation Oncology Group institutions worldwide.

RESULTS

Fifty-six patients met the eligibility criteria, and 63 tumors were treated: head and neck (27%), trunk (14%), upper extremities (27%), and lower extremities (32%). Median tumor size was 2.25 cm (range, 0.6-12 cm). T classification included T1, 40 patients (71%); T2, 12 patients (21%); and T3, 4 patients (7%). The median radiation dose was 35 Gy (range, 6-45 Gy). Complete clinical response (CCR) was achieved in 60 of 63 tumors (95%) and partial response in 3 tumors (5%). After CCR, 1 tumor recurred locally (1.7%) after 36 Gy and 7 months after RT. This was the only patient to die of disease.

CONCLUSIONS

Primary cutaneous anaplastic large cell lymphoma is a rare, indolent cutaneous lymphoma with a low death rate. This analysis, which was restricted to patients selected for treatment with radiation, indicates that achieving CCR was independent of radiation dose. Because there were too few failures (<2%) for statistical analysis on dose response, 30 Gy seems to be adequate for local control, and even lower doses may suffice.

An Index Case of Cutaneous Hodgkin Lymphoma and Review of the Literature

Hodgkin lymphoma (HL), although a common hematopoietic malignancy, presents as a primary cutaneous form in extraordinarily rare instances. In this study, we present a remarkable case of a 76-year-old woman with a history of bony metastatic breast cancer who developed multiple subcutaneous nodules on the left neck and scalp. A biopsy revealed the histological and immunohistochemical findings of classic HL. She was treated with systemic chemotherapy and quickly achieved disease remission. Five months later, she was alive and without evidence of lymphoma, consistent with our understanding of primary cutaneous HL as an indolent variant of HL.

ALK-positive (2p23 rearranged) anaplastic large cell lymphoma with localization to the skin in a pediatric patient

Anaplastic large cell lymphoma (ALCL) either as primary cutaneous or nodal disease is rare in children and difficult to distinguish, which is important both prognostically and for treatment purposes. We present a case of anaplastic lymphoma kinase (ALK)+ skin-limited ALCL that highlights this challenge and draws attention to pitfalls in assessing ALK status. The patient was an 11-year old girl with a twice recurrent nodule on her right shoulder. Each biopsy revealed a deep infiltrate of atypical lymphocytes that expressed CD3, CD4, CD43, CD45RO and CD30. The initial biopsy was epithelial membrane antigen (EMA)+ with vague cytoplasmic ALK-1 positivity by immunohistochemistry, while the second biopsy was EMA+ and nuclear ALK-1+. Fluorescence in situ hybridization analysis for an ALK (2p23) rearrangement of the first specimen was negative, while an ALK gene rearrangement was present in the second specimen. Therefore, this case was treated as nodal ALCL, despite negative bone marrow and radiographic imaging studies. The patient was treated with combination chemotherapy and remains disease-free. Demonstration of nuclear ALK-positivity, ALK (2p23) gene rearrangement is suggestive of systemic ALCL. Without evidence of systemic disease, this case highlights challenges of skin-limited ALCL, whose clinical behavior as either cutaneous ALCL systemic ALCL may not be immediately apparent.

Pathology of T-cell lymphomas: diagnosis and biomarker discovery

T-cell lymphomas are a group of predominantly rare hematologic malignancies that tend to recapitulate different stages of T-cell development, in a similar way that B-cell lymphomas do. As opposed to B-cell lymphomas, the understanding of the biology and the classification of T-cell lymphomas are somewhat rudimentary, and numerous entities are still included as 'provisional categories' in the World Health Classification of hematolopoietic malignancies. A relevant and useful classification of these disorders have been difficult to accomplish because of the rarity nature of them, the relative lack of understanding of the molecular pathogenesis, and their morphological and immunophenotypical complexity. Overall, T-cell lymphomas represent only 15 % of all non-Hodgkin lymphomas. This review is focused on addressing the current status of the categories of mature T-cell leukemias and lymphomas (nodal and extranodal) using an approach that incorporates histopathology, immunophenotype, and molecular understanding of the nature of these disorders, using the same philosophy of the most recent revised WHO classification of hematopoietic malignancies.

Analysis of clinical characteristics of 516 patients with non-Hodgkin's lymphoma in Shanghai area

The aim was to determine the clinical and cytogenetic characteristics of non-Hodgkin's lymphoma (NHL) in Shanghai. A retrospective analysis was conducted in 516 patients with NHL. Patient clinical data, including age, sex, diagnosis, immunophenotypes, and karyotypes, were collected. The median age was 58 years. There was a male predominance in all NHL, except extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. Patients with B cell NHL (1.5%) expressed CD3. T cell NHL patients (11.5%) expressed CD20. Epstein-Barr virus latent integral membrane protein 1, BCL6, CD10, Bcl-2, CD68, myeloperoxidase, CD99, CD30, CD15, and CD43 were present in various types of NHL. Complex karyotypes accounted for 92.3% of the 73.7% patients with abnormal karyotypes. Immunoglobin heavy chain gene translocation was present in 60.3% of B cell and 23.7% of T/NK cell neoplasms. Understanding the complex clinicopathological and molecular features of NHL may help with prognosis and serve as targets for treatments.

Anaplastic large cell lymphoma occurring in association with breast implants: review of pathologic and immunohistochemical features in 103 cases

Primary lymphomas of the breast are uncommon, and mostly of B-cell type. In the late 1990s, reports began to appear,primarily in the Pathology literature, of an apparently new category of breast lymphoma of T-cell type, having a particular association with silicone breast implants. This condition came to be recognized as implant-associated anaplastic large cell lymphoma.Appearing initially as individual case reports, the pathologic features were somewhat variable and the diagnosis was difficult. This review describes the pathologic and immunohistochemical features of implant-associated anaplastic large cell lymphoma of the breast drawn from a series of 103 cases. Recommendations are given for the management of removed implants, for the approach to differential diagnosis and the choice of initial immunohistochemical panels.

Acquisition of CD30 and CD15 accompanied with simultaneous loss of all pan-T-cell antigens in a case of histological transformation of mycosis fungoides with involvement of regional lymph node: an immunophenotypic alteration resembling classical Hodgkin lymphoma

: Acquired expression of CD30 is frequently noted in histological transformation of mycosis fungoides (MF), but simultaneous gain of CD15 accompanied with loss of pan-T-cell antigens are extremely rare. We report an unusual case of transformed MF with such an immunophenotypic alteration resembling classical Hodgkin lymphoma. The patient was an 81-year-old male with MF, who was initially treated with topical steroids and phototherapy. Despite the initial response, the patient developed a tumor-like skin lesion that was confirmed to be CD30-positive large T-cell lymphoma and was subsequently found to have a regional lymph node involvement by pleomorphic large cell lymphoma. Besides CD30, pleomorphic large cells were positive for CD15 but negative for all B cell- and T cell-specific antigens. Epstein-Barr virus was negative. Polymerase chain reaction-based assays demonstrated a clonal rearrangement of T-cell receptor gamma gene but detected no B-cell clone. The mechanism and clinical significance of this phenotypic conversion remains to be elucidated.

Mycosis fungoides: report of the 2011 Society for Hematopathology/European Association for Haematopathology workshop

Session 1 of the 2011 Workshop of the Society for Hematopathology and European Association for Haematopathology focused on mycosis fungoides (MF), the most common cutaneous lymphoma. The 62 cases in this case group demonstrated a wide spectrum of clinicopathologic features, including those seen in typical cases as well as those, by contrast, with atypical clinical history, morphology, immunophenotype, and/or genotype. Of the 62 cases, 27 (44%) were presented at the workshop and highlighted diagnostic challenges plus related issues. This report summarizes the approach recommended for making a confident diagnosis of MF and its clinically significant variants; emphasizes pitfalls in evaluating early MF, assessing nodal involvement, and diagnosing transformed MF; and discusses the relationship between MF and primary cutaneous CD30+ T-cell lymphoproliferative disorders. Last, Sézary syndrome is discussed, with concentration on those features distinct from MF.

Clonal T-cell receptor β-chain gene rearrangements in differential diagnosis of lymphomatoid papulosis from skin metastasis of nodal anaplastic large-cell lymphoma

BACKGROUND

In patients with a history of nodal anaplastic large-cell lymphoma (ALCL), differentiation of type C lymphomatoid papulosis from cutaneous involvement of systemic ALCL may be challenging because the 2 entities may exhibit identical histologic features. Although metastatic ALCL generally carries the same clone as the primary lymphoma, expression of a distinct clone likely represents a distinct process.

OBSERVATIONS

A 54-year-old white man had a history of anaplastic lymphoma kinase 1-negative ALCL in the right inguinal lymph node 6 years ago. A complete response was achieved after 6 cycles of CHOP (cyclophosphamide, doxorubicin, vincristine [Oncovin], and prednisone administered in 21-day cycles) and radiation therapy. After 3½ years, the patient observed waxing and waning papules and nodules. Examination of the biopsy specimen revealed a dense CD30(+) lymphocytic infiltrate; no evidence of systemic malignancy was evident on positron emission tomography. Although clinically the presentation was consistent with lymphomatoid papulosis, metastatic ALCL had to be excluded. Polymerase chain reaction analysis with T-cell receptor γ-chain gene rearrangement (TCR-γR) was performed on the original lymph node and new skin lesions. Results of the TCR-γR analysis were positive for clonality in both lesions. However, separate clonal processes were identified. The identification of distinct clones supported the clinical impression of lymphomatoid papulosis.

CONCLUSION

Polymerase chain reaction analysis of TCR-γR is a useful method for distinguishing different clonal processes and is recommended when differentiation of primary and secondary lymphoproliferative disorders is required.

Clinical applications of aptamers and nucleic acid therapeutics in haematological malignancies

Haematological malignancies result from a heterogeneous mix of genetic mutations and chromosome aberrations and translocations. Targeted therapies, such as the anti-CD20 antibody rituximab, or the BCR-ABL1 inhibitor imatinib, have proven to be effective treatments in the management of some of these malignancies, though relapsing or refractory disease is still common. Nucleic acid-based therapies have also entered the clinical arena, providing an alternative, complementary approach. The forerunner of these therapies were the antisense oligonucleotides, but their scope has expanded to include short-interfering RNA (siRNA), microRNA, decoy oligonucleotides and aptamers. These can be used either as mono-therapeutics, in conjunction with current chemotherapy regimens, or in combination with each other to improve therapeutic efficacy. Not only can these nucleic acid-based therapies silence target genes, they also have the potential of restoring gene function. While challenges remain in delivering effective doses of nucleic acid in vivo, these are steadily being met, suggesting an optimistic future in the treatment of haematological malignancies. This review summarizes the application of nucleic acid-based therapeutics, particularly aptamers, in the diagnosis and treatment of haematological malignancies.

Functions and uses of immunohistochemical stains in cutaneous infiltrates of hematopoietic origin: a review for the practicing dermatologist

BACKGROUND

Immunohistochemical stains, particularly those for cutaneous lymphomas, have similar-sounding names, which may lead to confusion among dermatologists who are not well versed in the terminology of the tools used for pathologic diagnosis. Also aiding in this is the fact that some familiar stains are constantly investigated for novel utility in different tumors, and a plethora of new stains regularly emerge in the peer-reviewed literature.

OBJECTIVE

To review the major stains encountered in dermatopathologic reports for cutaneous lymphomas. A select number of other stains are reviewed that are either new and under investigation in several cutaneous processes or have a new use described in recent reports.

METHODS

The peer-reviewed literature was searched and analyzed for the accepted purposes of using these markers.

RESULTS

All pertinent findings for these immunostains are reported with the purpose of educating the dermatology community.

CONCLUSION

This review serves as a reference to clarify potentially confusing immunohistochemical stains.

Specificity of IRF4 translocations for primary cutaneous anaplastic large cell lymphoma: a multicenter study of 204 skin biopsies

Current pathologic criteria cannot reliably distinguish cutaneous anaplastic large cell lymphoma from other CD30-positive T-cell lymphoproliferative disorders (lymphomatoid papulosis, systemic anaplastic large cell lymphoma with skin involvement, and transformed mycosis fungoides). We previously reported IRF4 (interferon regulatory factor-4) translocations in cutaneous anaplastic large cell lymphomas. Here, we investigated the clinical utility of detecting IRF4 translocations in skin biopsies. We performed fluorescence in situ hybridization (FISH) for IRF4 in 204 biopsies involved by T-cell lymphoproliferative disorders from 182 patients at three institutions. In all, 9 of 45 (20%) cutaneous anaplastic large cell lymphomas and 1 of 32 (3%) cases of lymphomatoid papulosis with informative results demonstrated an IRF4 translocation. Remaining informative cases were negative for a translocation (7 systemic anaplastic large cell lymphomas; 44 cases of mycosis fungoides/Sézary syndrome (13 transformed); 24 peripheral T-cell lymphomas, not otherwise specified; 12 CD4-positive small/medium-sized pleomorphic T-cell lymphomas; 5 extranodal NK/T-cell lymphomas, nasal type; 4 gamma-delta T-cell lymphomas; and 5 other uncommon T-cell lymphoproliferative disorders). Among all cutaneous T-cell lymphoproliferative disorders, FISH for IRF4 had a specificity and positive predictive value for cutaneous anaplastic large cell lymphoma of 99 and 90%, respectively (P=0.00002, Fisher's exact test). Among anaplastic large cell lymphomas, lymphomatoid papulosis, and transformed mycosis fungoides, specificity and positive predictive value were 98 and 90%, respectively (P=0.005). FISH abnormalities other than translocations and IRF4 protein expression were seen in 13 and 65% of cases, respectively, but were nonspecific with regard to T-cell lymphoproliferative disorder subtype. Our findings support the clinical utility of FISH for IRF4 in the differential diagnosis of T-cell lymphoproliferative disorders in skin biopsies, with detection of a translocation favoring cutaneous anaplastic large cell lymphoma. Like all FISH studies, IRF4 testing must be interpreted in the context of morphology, phenotype, and clinical features.

Anaplastic large cell lymphoma: twenty-five years of discovery

CONTEXT

The year 2010 commemorates the 25th year since the seminal publication by Karl Lennert and Harald Stein and others in Kiel, West Germany, describing an unusual large cell lymphoma now known as anaplastic large cell lymphoma (ALCL). Investigators at many universities and hospitals worldwide have contributed to our current in-depth understanding of this unique peripheral T-cell lymphoma, which in its systemic form, principally occurs in children and young adults.

OBJECTIVE

To summarize our current knowledge of the clinical and pathologic features of systemic and primary cutaneous ALCL. Particular emphasis is given to the biology and pathogenesis of ALCL.

DATA SOURCES

Search of the medical literature (Ovid MEDLINE In-Process & Other Non-Indexed Citations and Ovid MEDLINE: 1950 to Present [National Library of Medicine]) and more than 20 years of diagnostic experience were used as the source of data for review.

CONCLUSIONS

Based on immunostaining for activation antigen CD30 and the presence of dysregulation of the anaplastic lymphoma kinase gene (2p23), the diagnosis of ALCL has become relatively straightforward for most patients. Major strides have been made during the last decade in our understanding of the complex pathogenesis of ALCL. Constitutive NPM-ALK signaling has been shown to drive oncogenesis via an intricate network of redundant and interacting pathways that regulate cell proliferation, cell fate, and cytoskeletal modeling. Nevertheless, pathomechanistic, therapeutic, and diagnostic challenges remain that should be resolved as we embark on the next generation of discovery.

MUM1/IRF4: A Review

MUM1/IRF4 protein is a member of the interferon regulatory factor (IRF) family of transcriptional factors initially described as downstream regulators of interferon signaling. The quantity of this factor varies within the hematopoietic system in a lineage and stage-specific way. It is considered to be a key regulator of several steps in lymphoid, myeloid, and dendritic cell differentiation and maturation. MUM1/IRF4 expression is observed in many lymphoid and myeloid malignancies, and may be a promising target for the treatment of some of these neoplasms. We reviewed the literature on MUM1/IRF4, with emphasis on the pathologic aspects of this marker in reactive and malignant hematologic and nonhematologic conditions.

Genome-wide analysis of cutaneous T-cell lymphomas identifies three clinically relevant classes

This study was undertaken to identify recurrent genetic alterations of the three main types of cutaneous T-cell lymphomas (CTCLs): mycosis fungoides (MF), Sézary syndrome (SS), and cutaneous anaplastic large-cell lymphoma (CALCL). Using array-based comparative genomic hybridization, the molecular cytogenetic profiles of 72 samples obtained from 58 patients with CTCL corresponding to 24 transformed MF (T-MF), 16 SS, and 18 CALCLs were determined. T-MF was characterized by gains of 1q25-31, 7p22-11.2, 7q21, 7q31, and 17q12, and losses of 9p21, 10p11.2, and 10q26. SS exhibited gains of 8q23-24.3 and 17q23-24, as well as losses of 9p21, 10p12-11.2, 10q22-24, 10q25-26, and 17p13-q11.1. Finally, CALCL exhibited 6q27 and 13q34 losses. Such imbalances were statistically associated with one CTCL subtype. Unsupervised hierarchical clustering defined three categories of clinical relevance: (1) CALCL apart from epidermotropic-CTCL, (2) an SS-only category, and (3) a mixed category with T-MF and SS cases, with both primary and secondary SS cases. In rare cases, the genetic classification did not correspond to the inclusion diagnosis, possibly reflecting the association of two diseases in the same patient or initial misdiagnosis according to follow-up. Finally, different samples in the same patient clustered together, showing reproducibility of such a classifier.

Cutaneous CD30 lymphoproliferative disorders and similar conditions: a clinical and pathologic prospective on a complex issue

We elaborate on the diagnosis of CD30 positive cutaneous lymphoproliferative conditions including the various clinical and pathological presentations, our understanding of its pathomechanisms and prognostic implications. The most common reactive conditions that can simulate CD30 lymphoproliferative conditions, including arthropod bite reactions, various viral infections, pityriasis lichenoides and lymphocytic papules in myelodysplastic syndrome, are discussed in detail.