Subcutaneous panniculitis-like T-cell lymphoma in the pediatric age group: a lymphoma of low malignant potential

Pediatric cutaneous T-cell neoplasm and mimics with gamma-delta expression: Not always aggressive

Pediatric cutaneous T-cell lymphoma with γδ immunophenotype is extremely rare. Only a few cases of γδ T-cell neoplasm have been reported in the literature, and therefore little is known whether γδ T-cell neoplasms in children are distinct from their adult counterparts with respect to the clinicopathological presentation, behavior, and prognosis. In this study, we demonstrate three unique pediatric cutaneous T-cell neoplasm and mimics with increased γδ T cells. All cases showed an indolent clinical course.

Panniculitic primary cutaneous gamma delta T-cell lymphoma with concomitant features of autoimmune disease emphasizing a pathophysiologic continuum of lupus profundus with the panniculitic T cell lymphomas

Certain T-cell lymphomas exhibit unique homing properties of the neoplastic lymphocytes for the subcutaneous fat. There are two primary forms of subcutaneous panniculitic lymphomas of T-cell origin. One falls under the designation of primary cutaneous gamma-delta T-cell lymphomas (PGD-TCL) whereby there is dominant involvement of the fat defininng a panniculitic form of PGD-TCL. The neoplastic cells are of the gamma-delta subset and are either double negative for CD4 and CD8 and/or can express CD8. They often have an aggressive clinical course. The other form of panniculitic T-cell lymphoma falls under the designation of subcutaneous panniculitis-like T-cell lymphoma (SPTCL). It represents a subcutaneous lymphoma derived from CD8+ T cells of the alpha-beta subset and typically has an indolent course. These two forms of panniculitic T-cell lymphoma exhibit overlapping histologic features with lupus profundus (LP), a putative form of panniculitic T-cell dyscrasia. We present three cases of PGD-TCL of the fat in the setting of lupus erythematosus (LE) (two cases) and dermatomyositis (DM) (one case), respectively. There were concurrent features of LE and DM in their lymphoma biopsies in two cases while a prior biopsy in one was interpreted as LP. In this latter case, the LP diagnosis presaged the diagnosis of panniculitic PGD-TCL by three years. One patient diagnosed with panniculitic PGD-TCL had hemophagocytic syndrome after developing a lupus-like complex including certain supportive serologies such as antibodies to double-stranded DNA following initiation of statin therapy. The second patient presented with PGD-TCL and concomitant features of anti-nuclear matrix 2 (NXP2) DM. The third patient presented in 2003 with LP and overlying skin features of acute LE, initially responding to Plaquenil, and then four years later was diagnosed with PGD-TCL heralded by Plaquenil treatment resistance. Two of the patients died of their lymphoma. All biopsies showed a characteristic histopathology of PGD-TCL. In two cases, the PGD-TCL was associated with overlying LE-cutaneous findings; another case had skin changes of lymphocyte-rich DM. In two cases, the MXA stain was strikingly positive, the surrogate type I interferon marker that is typically upregulated in biopsies of LE and DM. There are eight prior reported cases describing SPTCL with concomitant cutaneous changes of LE. In six cases there was an established history of LE, including LP responding initially to Plaquenil, similar to one of our cases. In the context of SPTCL or panniculitic PGD-TCL, panniculitic T-cell lymphomas can be associated with concomitant clinical and histologic features of LE or DM, including an upregulated type I interferon signature. Identifying histologic features associated with either of these prototypic autoimmune conditions should not be considered exclusionary to diagnosing any panniculitic T-cell lymphoma. A clinical, histomorphologic, and pathophysiologic continuum exists with LP, SPTCL and panniculitic PGD-TCL.

Biopathology of childhood, adolescent and young adult non-Hodgkin lymphoma

Mature non-Hodgkin lymphomas (NHL) in the childhood, adolescent and young adult (CAYA) population are rare and exhibit unique clinical, immunophenotypic and genetic characteristics. Application of large-scale unbiased genomic and proteomic technologies such as gene expression profiling and next generation sequencing (NGS) have led to enhanced understanding of the genetic basis for many lymphomas in adults. However, studies to investigate the pathogenetic events in CAYA population are relatively sparse. Enhanced understanding of the pathobiologic mechanisms involved in non-Hodgkin lymphomas in this unique population will allow for improved recognition of these rare lymphomas. Elucidation of the pathobiologic differences between CAYA and adult lymphomas will also lead to the design of more rational and much needed, less toxic therapies for this population. In this review, we summarize recent insights gained from the proceedings of the recent 7th International CAYA NHL Symposium held in New York City, New York October 20-23, 2022.

Diagnosis and management of cutaneous lymphomas and lymphoid proliferations in children, adolescents and young adults (CAYA)

Cutaneous lymphomas and lymphoid proliferations (LPD) in children, adolescents, and young adults (CAYA) are a heterogeneous group of lymphoid neoplasms that present formidable diagnostic challenges to clinicians and pathologists alike. Although rare overall, cutaneous lymphomas/LPD occur in real-world settings and awareness of the differential diagnosis, potential complications, and various therapeutic approaches will help ensure the optimal diagnostic work-up and clinical management. Lymphomas/LPD involving the skin can occur as primary cutaneous disease in a patient that characteristically has lymphoma/LPD confined to the skin, or as secondary involvement in patients with systemic disease. This review will comprehensively summarize both primary cutaneous lymphomas/LPD that occur in the CAYA population as well as those CAYA systemic lymphomas/LPD with propensity for secondary cutaneous involvement. Focus on the most common primary entities occurring in CAYA will include lymphomatoid papulosis, primary cutaneous anaplastic large cell lymphoma, mycosis fungoides, subcutaneous panniculitis-like T-cell lymphoma, and hydroa vacciniforme lymphoproliferative disorder.

A retrospective study of 18 children with subcutaneous panniculitis-like T-cell lymphoma: multidrug combination chemotherapy or immunomodulatory therapy?

BACKGROUND

Subcutaneous panniculitis T-cell lymphoma (SPTCL) is a rare, cytotoxic T-cell lymphoma with which some patients have accompanying hemophagocytic syndrome (HPS). There is currently no standard treatment regimen. In the past, the most commonly used treatment was multidrug chemotherapy. In contrast, numerous case reports or small series suggest that immunosuppressive drugs could also be effective for some patients. Since this NHL subtype is extremely rare in children and adolescents, to improve the understanding of this disease and standardize its rational treatment, we retrospectively summarized the treatment regimens of 18 pathologically diagnosed children with SPTCL to compare the clinical efficacy of multidrug chemotherapy and immunomodulatory therapy.

RESULTS

The median age of onset was 11.1 years. Painless subcutaneous nodules or skin patchy lesions were found in all patients, most commonly involving the lower extremities and/or trunk. Before January 1, 2019, the treatment was mainly chemotherapy, and 10 patients were initially treated with chemotherapy, among whom was one patient who progressed during initial treatment, was voluntarily discharged and was subsequently lost to follow-up, one patient who died of disease progression, and the remaining 8 patients who all achieved sustained remission, with a complete remission (CR) rate of 80% (8/10). Corticosteroids combined with cyclosporine A or ruxolitinib were the most common initial immunosuppressive agents at our center after January 1, 2019 and had a CR rate of 71.4% (5/7). In addition, 1 patient achieved partial remission (PR) during follow-up, and one had autologous hematopoietic stem cell transplantation (AHSCT) after 4 months of drug withdrawal. There were 7 patients (38.9%, one case in chemotherapy group and six cases in immunotherapy group) with HPS and 4/5 screened patients (80%) with positive HAVCR2 gene mutations. The median follow-up was 17 months.

CONCLUSION

The prognosis of SPTCL is relatively good. Previous multi-drug and long-term chemotherapy treatment has clear efficacy, and recent immunomodulatory therapy as pre-chemotherapy therapy can also benefit patients.

Subcutaneous panniculitis-like T-cell lymphoma in a 14-year-old female homozygous for HAVCR2 mutation

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma preferentially involving subcutis. A link between patients with SPTCL and HAVCR2 mutations has recently been discovered. We present a 14-year-old girl of Chinese heritage who was diagnosed with SPTCL in the context of homozygous HAVCR2 status for c.245A>G p. (Tyr82Cys) and achieved complete remission after treatment with cyclosporin and steroids. Dermatologists should be aware of the diagnostic, management and familial genetic counselling utility of HAVCR2 for investigating and managing patients with SPTCL.

Concurrent Subcutaneous Panniculitis-like T-Cell Lymphoma and B-Cell Acute Lymphoblastic Leukemia in 2 Pediatric Patients

Subcutaneous panniculitis-like T-cell lymphoma is a cutaneous lymphoma characterized by CD8+ T-cell infiltrate in the subcutis that is rare in children. Acute lymphoblastic lymphoma is the most common pediatric malignancy and often presents with fevers and pancytopenia. Herein, we report 2 pediatric patients presenting with subcutaneous panniculitis-like T-cell lymphoma and B-cell acute lymphoblastic lymphoma, distinct hematologic malignancies arising from different lymphoid lineages, with no identifiable germline cancer predisposition.

Single-Cell RNA-seq Reveals Characteristics of Malignant Cells and Immune Microenvironment in Subcutaneous Panniculitis-Like T-Cell Lymphoma

Background

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a malignant primary T-cell lymphoma that is challenging to distinguish from autoimmune disorders and reactive panniculitides. Delay in diagnosis and a high misdiagnosis rate affect the prognosis and survival of patients. The difficulty of diagnosis is mainly due to an incomplete understanding of disease pathogenesis.

Methods

We performed single-cell RNA sequencing of matched subcutaneous lesion tissue, peripheral blood, and bone marrow from a patient with SPTCL, as well as peripheral blood, bone marrow, lymph node, and lung tissue samples from healthy donors as normal controls. We conducted cell clustering, gene expression program identification, gene differential expression analysis, and cell-cell interaction analysis to investigate the ecosystem of SPTCL.

Results

Based on gene expression profiles in a single-cell resolution, we identified and characterized the malignant cells and immune subsets from a patient with SPTCL. Our analysis showed that SPTCL malignant cells expressed a distinct gene signature, including chemokines families, cytotoxic proteins, T cell immune checkpoint molecules, and the immunoglobulin family. By comparing with normal T cells, we identified potential novel markers for SPTCL (e.g., CYTOR, CXCL13, VCAM1, and TIMD4) specifically differentially expressed in the malignant cells. We also found that macrophages and fibroblasts dominated the cell-cell communication landscape with the SPTCL malignant cells.

Conclusions

This work offers insight into the heterogeneity of subcutaneous panniculitis-like T-cell lymphoma, providing a better understanding of the transcription characteristics and immune microenvironment of this rare tumor.

TIM-3 deficiency presenting with two clonally unrelated episodes of mesenteric and subcutaneous panniculitis-like T-cell lymphoma and hemophagocytic lymphohistiocytosis

This report offers novel clinical and diagnostic aspects of the association between germline mutations in HAVCR2 and subcutaneous panniculitis-like T-cell lymphoma (SPTCL). The patient presented with panniculitis-like T-cell lymphoma involving mesenteric fatty tissue associated with hemophagocytic lymphohistiocytosis (HLH). Five years later, he developed a clonally unrelated SPTCL and underwent hematopoietic stem cell transplantation. Retrospectively, he was found to carry germline mutations in HAVCR2 associated with reduced T-cell immunoglobulin mucin-3 (TIM-3) expression. We show that mesenteric fatty tissue localization of SPTCL can be the presenting manifestation of TIM-3 deficiency, that this condition predisposes to recurrent lymphoma, and that flow cytometry is a possible screening tool.

Efficacy of ruxolitinib in subcutaneous panniculitis-like T-cell lymphoma and hemophagocytic lymphohistiocytosis

First evidence of ruxolitinib efficacy for subcutaneous panniculitis-like T-cell lymphoma with hemophagocytic lymphohistiocytosis. Supporting rationale for ruxolitinib use, not more aggressive treatment, in this context, questioning this condition’s neoplastic nature.

A Systematic Approach to the Cutaneous Lymphoid Infiltrates: A Clinical, Morphologic, and Immunophenotypic Evaluation

CONTEXT.—

The evaluation of cutaneous lymphoid infiltrates, both neoplastic and inflammatory, occurs very frequently in routine dermatopathologic examination and consultation practices. The "tough" cutaneous lymphoid infiltrate is feared by many pathologists; skin biopsies are relatively small, whereas diagnostic possibilities are relatively broad. It is true that cutaneous lymphomas can be difficult to diagnose and that in many circumstances multiple biopsies are required to establish a correct diagnostic interpretation. As a reminder, one should understand that low-grade cutaneous lymphomas are indolent disorders that usually linger for decades and that therapy does not result in disease cure. It is also important to remember that in most circumstances, those patients will die from another process that is completely unrelated to a diagnosis of skin lymphoma (even in the absence of specific therapy).

OBJECTIVE.—

To use a clinicopathologic, immunophenotypic, and molecular approach in the evaluation of common lymphocytic infiltrates.

DATA SOURCES.—

An in-depth analysis of updated literature in the field of cutaneous lymphomas was done, with particular emphasis on updated terminology from the most recent World Health Organization classification of skin and hematologic tumors.

CONCLUSIONS.—

A diagnosis of cutaneous lymphoid infiltrates can be adequately approached using a systematic scheme following the proposed ABCDE system. Overall, cutaneous T- and B-cell lymphomas are rare and "reactive" infiltrates are more common. Evaluation of lymphoid proliferations should start with a good sense of knowledge of the clinical presentation of the lesions, the clinical differential considerations, and a conscientious and appropriate use of immunohistochemistry and molecular tools.

Frequent germline mutations of HAVCR2 in sporadic subcutaneous panniculitis-like T-cell lymphoma

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare subtype of peripheral T-cell lymphoma affecting younger patients and associated with hemophagocytic lymphohistiocytosis. To clarify the molecular pathogenesis of SPTCL, we analyzed paired tumor and germline DNAs from 13 patients by whole-exome sequencing. All cases were Asians and were phenotypically sporadic with no family history of SPTCL. Consistent with a recent report, germline mutations in HAVCR2, encoding T-cell immunoglobulin mucin 3 (TIM3), were identified in 11 of 13 (85%) cases. All mutated cases were primary SPTCL, whereas the 2 cases without mutation were secondary SPTCL associated with underlying diseases, including viral infection and autoimmune disease. Ten patients harbored homozygous p.Y82C mutations, and 1 showed compound heterozygous mutations (p.Y82C and p.T101I). Both missense mutations altered highly conserved residues located in the extracellular immunoglobulin variable-like domain. According to the Genome Aggregation Database of >138 500 general individuals, both mutations were documented with minor allele frequencies < 0.007, indicating remarkable enrichment of these HAVCR2 alleles in SPTCL. SPTCL cells also harbored somatic mutations (6.2 per patient) that are frequently identified in genes associated with epigenetic regulation and signal transduction. In conclusion, individuals harboring biallelic HAVCR2 (TIM3) germline mutations were highly susceptible to sporadic SPTCL, which was also associated with clonal somatic mutations.

Pediatric Subcutaneous Panniculitis-like T-Cell Lymphoma With Hemophagocytosis Showing Complete Resolution With the BFM90 Protocol: Case Report and Review of Literature

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a distinct subtype of peripheral T-cell lymphoma associated with aggressive clinical behavior. Since its original description, it has continued to be a rare disease, and <200 cases have been reported in literature. We report an 11-year-old boy who presented with SPTCL and hemophagocytic lymphohistiocytosis (HLH) and responded to high-dose multiagent chemotherapy. He presented with steroid refractory erythematous, raised plaques over his face, trunk, and limbs over a period of 15 months treated elsewhere. Repeat evaluation in our center was consistent with SPTCL with features of HLH. He was initiated on therapy with the BFM90 protocol, which led to complete morphologic and biochemical remission. No single-best treatment regimen has been described for SPTCL with HLH in literature, and high-dose chemotherapy has shown good long-term remissions in the literature. The presence of SPTCL with HLH and systemic symptoms should prompt treatment with high-dose multiagent chemotherapy rather than Cyclophosphamide, Vincristine, Adriamycin, Prednisolone-like therapy. BFM90 is one such regimen that is well tolerated, and it can induce significant clinical and biochemical responses.

Treatment and prognosis of mature (non-anaplastic) T- and NK-cell lymphomas in childhood, adolescents, and young adults

Paediatric non-Hodgkin lymphomas (pNHL) are a diverse group of malignancies characterised by nodal and/or extranodal involvement. Less common pNHL forms include those derived from mature T- and natural killer (NK) cells. Much of our current understanding of paediatric mature (non-anaplastic) T/NK-cell lymphomas with respect to pathogenesis, diagnosis and treatment is extrapolated from adult literature. At the Sixth International Symposium on Childhood, Adolescent and Young Adult Non-Hodgkin Lymphoma, convened September 26-29, 2018 in Rotterdam, The Netherlands, some important aspects on diagnosis and outcomes of mature (non-anaplastic) T/NK-cell lymphoma in children and adolescents were discussed and will be reviewed in here.

Hematopoietic stem cell transplantation for subcutaneous panniculitis-like T-cell lymphoma: single center experience in an Asian population

Subcutaneous panniculitis-like T-cell lymphoma (SPTL) is a rare form of cytotoxic T-cell lymphoma. It is believed that SPTL in patients without hemophagocytic syndrome (HPS) follows an indolent course; in contrast, SPTL in patients with HPS has been associated with unfavorable survival. To provide more clinical data on SPTL in Asian populations and to identify optimal therapeutic strategies for SPTL, we assessed the clinicopathological features and long-term follow-up data of 10 Taiwanese SPTL patients diagnosed at a single center. Our study demonstrates a group of patients with high incidence of HPS (50%), rather aggressive courses, and early progression. A total of eight patients underwent hematopoietic stem cell transplant (HSCT), including one autologous HSCT and seven allogeneic HSCT. Seven of eight patients receiving HSCT achieved durable remission and maintained in remission for over 30 months (range 30-132 months). There was no difference in 3-year survival of patients with HPS (80%) compared with patients without HPS (80%). Of long-term survivors in the HPS group, three of four received HSCT (autologous HSCT, n = 1; allogeneic HSCT, n = 2). Our study indicated that HSCT is a curative option for eligible SPTL patients with HPS.

Cutaneous Hematolymphoid and Histiocytic Proliferations in Children

This article focuses on cutaneous hematopoietic neoplasms that are more likely to be encountered in the pediatric age-group and includes both lymphoproliferative and histiocytic disorders. The cutaneous hematologic disorders in children have a different epidemiologic profile to what is seen during adulthood. Although mycosis fungoides is the most frequent form of cutaneous lymphoma in adults, it is very rare in children. Because lymphoblastic leukemias and lymphomas are more frequent in the pediatric setting, cutaneous leukemic infiltrates are relatively common in this age-group. Similarly, histiocytic disorders are more common in children, particularly Langerhans cell histiocytosis and juvenile xanthogranuloma. Notably, the histiocytic disorders have undergone significant modifications on their nomenclature in the basis of the molecular characteristics that are present in them. A summary of the most frequent cutaneous hematopoietic disorders in children will be discussed further in this review.

Subcutaneous Panniculitis-Like T-Cell Lymphoma Presenting as a Local Inflammation of a Thigh in an 8-Month-Old Child

During infancy, skin inflammation is usually treated in basic pediatric care. In this study, we present a case of an 8-month-old girl with a 2-month history of an inflammation of the thigh treated locally by ointments and oral antibiotics in basic and dermatological care. The patient had a history of fever, sweating, and failure to thrive. The lactate dehydrogenase was elevated up to 869 U/L with low C-reactive protein (1.04 mg/L). Magnetic resonance imaging of the thigh reassured the diagnosis of local inflammation. Intravenous antibiotic caused mild local improvement, but the episodes of high fever sustained. The patient was transferred to our pediatric surgery department for treatment and surgical biopsy of the lesion. Histopathological examination confirmed a subcutaneous panniculitis-like T-cell lymphoma, which is a rare cytotoxic T-cell lymphoma representing less than 1% of non-Hodgkin lymphomas, uncommon in children. The patient was introduced to a chemotherapy protocol EURO-LB 2002 with good response. In a skin lesion that is associated with systemic symptoms and responding untypically to antibiotic treatment malignancy should be considered and biopsy not be postponed.

Useful Parameters for Distinguishing Subcutaneous Panniculitis-like T-Cell Lymphoma From Lupus Erythematosus Panniculitis

Some cases of subcutaneous panniculitis-like T-cell lymphoma (SPTCL) and lupus erythematosus panniculitis (LEP) demonstrate clinical and histopathologic overlap, raising the possibility that they represent opposite ends of a disease spectrum. SPTCL, however, is typically associated with greater morbidity and risk for hemophagocytic lymphohistiocytosis (HLH); therefore, diagnostic distinction is clinically important. We present the histopathologic, immunophenotypic, and molecular findings with long-term clinical follow-up of 13 patients with SPTCL (median, 64 mo follow-up) and 7 with LEP (median, 50 mo follow-up) in our multidisciplinary cutaneous oncology clinic. Six SPTCL patients developed HLH, including 2 under the age of 21 years. In the SPTCL group, 2 of 13 patients died of disease. In contrast, we had no mortality or development of HLH in our LEP cohort. We demonstrate that a limited panel (Ki-67, CD3, CD4, and CD8 immunostains) reveals foci of "Ki-67 hotspots" enriched in cytotoxic atypical CD8+ T cells in SPTCL. Ki-67 hotspots were not identified in LEP, thus aiding the distinction of SPTCL from LEP. Lymphocyte atypia combined with adipocyte rimming of CD8+ T cells within Ki-67 hotspots was also highly specific for the diagnosis of SPTCL. Hyaline lipomembranous change, B-cell aggregates, plasmacytoid dendritic cell clusters, and plasma cell aggregates favored the diagnosis of LEP but were identified in some cases of SPTCL including patients with HLH. We confirm that SPTCL and LEP can show significant histologic overlap, suggest a role for high-throughput sequencing in confirming neoplastic clones, and introduce the concept of SPTCL "Ki-67 hotspots" in evolving disease.

Cutaneous Lymphomas with Cytotoxic Phenotype

Primary cutaneous cytotoxic lymphomas are T-cell or natural killer-cell lymphomas that express 1 or more cytotoxic markers. These neoplasms constitute a spectrum of diseases. In this review, an overview of clinical, morphologic, and phenotypical features of each subtype is provided. Differential diagnosis is discussed with attention to scenarios in which diagnostic difficulties are most frequently encountered.

Primary Cutaneous Lymphomas in Children and Adolescents

Primary cutaneous lymphomas are rare in children and mostly represented by mycosis fungoides and CD30(+) lymphoproliferative disorders. Most pediatric cutaneous lymphomas have similar clinical/pathological features as their adult counterparts, particularly the T-cell subtypes. With regard to outcome, adult cutaneous mature T-cell lymphomas have a tendency to progression, while this appears to be relatively infrequent in children. The outcome of cutaneous B-cell lymphomas depends on subtype, with the B-lymphoblastic entity being associated with similar outcomes to precursor B acute lymphoblastic leukemia, while there are insufficient data on other entities. The diagnosis and treatment of these patients require a close collaboration between experienced pediatric pathologists, dermatologists, and oncologists. Prospective collection of longitudinal clinical and biological data from children with these rare lymphomas is needed to better understand their biological and clinical behavior and to ultimately discover the best therapeutic strategies.

Lymphocytic panniculitis: an algorithmic approach to lymphocytes in subcutaneous tissue

The diagnosis of panniculitis is a relatively rare occurrence for many practising pathologists. The smaller subset of lymphocyte-predominant panniculitis is further complicated by the diagnostic consideration of T cell lymphoma involving the subcutaneous tissue, mimicking inflammatory causes of panniculitis. Accurate classification of the panniculitis is crucial to direct clinical management as treatment options may vary from non-medical therapy to immunosuppressive agents to aggressive chemotherapy. Many diseases show significant overlap in clinical and histological features, making the process of determining a specific diagnosis very challenging. However, with an adequate biopsy including skin and deep subcutaneous tissue, a collaborative effort between clinician and pathologist can often lead to a specific diagnosis. This review provides an algorithmic approach to the diagnosis of lymphocyte-predominant panniculitis, including entities of septal-predominant pattern panniculitis (erythema nodosum, deep necrobiosis lipoidica, morphea profunda and sclerosing panniculitis) and lobular-predominant pattern panniculitis (lupus erythematous panniculitis/lupus profundus, subcutaneous panniculitis-like T cell lymphoma, cutaneous γ-δ T cell lymphoma, Borrelia infection and cold panniculitis).

Rare Pediatric Non-Hodgkin Lymphomas: A Report From Children's Oncology Group Study ANHL 04B1

BACKGROUND

Non-Hodgkin lymphoma (NHL) is a relatively common malignancy in pediatric patients; however, a small subgroup have unusual lymphoma subtypes for the pediatric population.

PROCEDURE

The Children's Oncology Group Rare and Cutaneous NHL registry's (protocol ANHL 04B1) main objectives were to determine the pathologic, biologic, and clinical features of rare and cutaneous pediatric NHL and establish a bank of centrally reviewed tissue specimens. We report the clinical data, treatment data, and outcome for rare pediatric NHL.

RESULTS

In 101 lymphomas, there is a 97.8% concordance between the reviewing study pathologists and an 87.6% concordance between the central and institutional pathology review. Samples in the specimen bank include primary tumor tissue that is snap frozen, in paraffin blocks, or H&E-stained and unstained paraffin slides as well as blood, serum, and bone marrow. This descriptive analysis shows that children with pediatric follicular lymphoma, mucosa-associated lymphoid tissue, nodal marginal zone lymphoma, primary cutaneous, primary central nervous system lymphoma, and subcutaneous panniculitis-like T-cell lymphomas have 100% survival at a median of 2 years from enrollment. There are early deaths, mostly from progressive disease, in subjects with peripheral T-cell (not otherwise specified), NKT, and hepatosplenic T-cell lymphomas.

CONCLUSIONS

This registry provides high-quality biologic specimens with clinical data to investigators working on the biology of these unusual pediatric diseases.

Mature T- and NK-cell non-Hodgkin lymphoma in children and young adolescents

Mature T/Natural killer (NK)-cell neoplasms of children and the young adolescent population exhibit higher prevalence in Central and South American and Asian populations and many are associated with Epstein-Barr virus (EBV). They are represented in large part by extranodal T/NK cell lymphomas- nasal-type or extra nasal-type, chronic lymphoproliferative disorders of T/NK cells or chronic active EBV disease, systemic EBV-positive lymphoproliferative disorders of childhood, hydroa vacciniforme-like lymphoma, hepatosplenic T-cell lymphoma and primary cutaneous gamma/delta T-cell lymphoma among others. Many T/NK cell neoplasms in this age group are derived from cells of the innate immune system, in contrast to adults where they are predominantly from the adaptive immune system. The genetic basis of T/NK cell lymphomas in children and young adolescents remains largely unknown. Anthracycline-based regimens and haematopoietic stem cell transplants (allogeneic and autologous) are current treatment modalities, however it is anticipated that novel targeted therapeutic agents will be available in the near future.

Subcutaneous Panniculitis-Like T-Cell Lymphoma with Hemophagocytic Syndrome in a Child

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) characterized by subcutaneous infiltration of pleomorphic T-cells of the α/β phenotype rarely affects children. Development of hemophagocytic syndrome (HPS) leads to a poor prognosis with this otherwise indolent lymphoma. We report a case of SPTCL in a 5-year-old child complicated by HPS treated successfully with combination chemotherapy. We discuss the potential pitfalls in reaching an early diagnosis and challenges in its management. Previously reported cases of SPTCL with HPS in children are briefly reviewed.

[Subcutaneous panniculitis-like T-cell lymphoma : Two case reports]

Histopathology, immunohistochemical, and molecular genetic findings revealed the diagnosis of subcutaneous panniculitis-like T-cell-lymphoma in two patients, aged 44 and 70 years. The clinical morphology of the lymphoma manifestations showed varied significantly. One patient presented with a singular erythematous nodule in the chin region. The other patient suffered from extended plate-like resistances and atrophy of the face, upper arms and left breast. Hemophagocytic syndrome was not present in either patient. Prognosis of subcutaneous panniculitis-like T-cell lymphoma without associated hemophagocytic syndrome is reported to be favorable. Radiotherapy of the singular lesion on the chin and systemic corticosteroids of the extended plaques induced complete remission in both patients.

Subcutaneous panniculitis-like T-cell lymphoma: Pediatric case series demonstrating heterogeneous presentation and option for watchful waiting

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) and primary cutaneous gamma delta T-cell lymphoma (PCGD-TCL) were initially both classified as subcutaneous panniculitis-like T-cell lymphoma. In 2008, SPTCL with alpha-beta T-cell receptor subtype was separated from primary cutaneous gamma delta T-cell lymphomas (PCGD-TCL). We report four pediatric cases that demonstrate the heterogeneity of each disease and show that PCGD-TCL in children can have an indolent course, whereas SPTCL can behave aggressively. Three patients had spontaneous, durable remissions without treatment, whereas the one patient with disease progression was treated successfully. Watchful waiting may thus be appropriate for initial management of children.

Uncommon non-Hodgkin lymphomas of childhood: pathological diagnosis, clinical features and treatment approaches

We provide a review of the pathological and clinical features for uncommon B-cell and T-cell lymphomas of childhood with a specific focus on advances in treatment approaches and outcomes. There is clearly a need for prospective investigation of both the clinical and biological features of the uncommon non-Hodgkin lymphoma subtypes in childhood. These results should lead to more uniform and more effective treatment approaches.

Paediatric cutaneous lymphomas: a review and comparison with adult counterparts

Primary cutaneous lymphomas (CL) in children is rare. Only a few studies focused specifically on paediatric CL and therefore little is known whether primary CL in children are similar to or different from their adult counterparts with respect to the clinicopathological presentation, behaviour and prognosis. An extensive literature search using PubMed/MEDLINE from January 1995 through July 2014 was undertaken for articles reporting cases of paediatric CL. In addition, we identified 31 children with CL in our institutions. Mycosis fungoides and lymphomatoid papulosis are the two most prevalent lymphoma forms in children. A few entities of cutaneous lymphomas such as cutaneous diffuse large B-cell lymphoma leg type, and Sézary syndrome have not been reported so far in children. Other lymphoma entities such as hydroa vacciniforme-like lymphoma are mostly seen in certain geographic areas (Asia, Central and South America). In the paediatric population, low-malignant indolent forms such as primary cutaneous marginal zone lymphoma and primary cutaneous follicle centre lymphoma are very rare, whereas the more aggressive forms of B-cell lymphomas, precursor lymphoblastic lymphomas, and blastic plasmacytoid dendritic cell neoplasm are the most common forms in children, mostly involving the skin secondarily. Most paediatric lymphomas have similar clinicopathological features and course as their adults counterparts, particularly in the group of cutaneous T-cell lymphomas. The spectrum of cutaneous B-cell lymphomas in children significantly differs from the one in adults. Diagnostic work-up and treatment of paediatric patients with lymphomas are best achieved in close collaboration with paediatric haematopathologists and oncologists.

Progressive and painful wound as a feature of subcutaneous panniculitis-like T-cell lymphoma (SPTCL): report of a case and review of literature

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is an uncommon extranodal non-Hodgkin lymphoma, with an aggressive course with no well-defined treatment. This article describes a 56-year-old man, treated surgically 7 months earlier for a subcutaneous nodosity near the left axilla, presenting with a progressive inflamed wound, pain, and high fever (39 °C). Treatment with systemic antibiotics and topical anti-inflammatory dressings failed. After 7 months, the patient was diagnosed with SPTCL based on biopsy results and a multidisciplinary consultation. While undergoing systemic chemotherapy with corticosteroid therapy, his wound become more painful, larger, and covered with necrotic tissue. Fifty days after chemotherapy with corticosteroid therapy, his wound became seriously painful and increasingly necrotic. He developed a serious stomachache and abdominal distension, rapidly became comatose, and died. The aim of this case report is to present our experience of the different clinical signs of SPTCL to expedite its early diagnosis in future. We summarize the main clinical characteristics of SPTCL as a rapidly progressing and increasingly painful wound with necrotic tissue, involving a multisystem disorder, which is easily misdiagnosed, responds poorly to corticosteroid and chemotherapy treatments, and has a high mortality rate. The pathological characteristics are early inflammation, advancing to profuse infiltration of the subcutaneous adipose tissues by CD3(+) and/or CD8(+) T-cell lymphoma cells. Clinicians must cooperate with pathologists and oncologists to diagnose this disease as soon as possible and to avoid a misdiagnosis. The use of antibiotic and painkillers should minimize the patient's discomfort and control rapid wound development. Future studies are required to investigate the optimal wound treatment and whether the necrotic tissue should be removed.

Pediatric subcutaneous panniculitis-like T-cell lymphoma with favorable result by immunosuppressive therapy: a report of two cases

Subcutaneous panniculitis-like T-cell lymphoma (SPTL) is a rare type of skin lymphoma. Histopathology mimicking a lobular panniculitis makes it difficult to distinguish SPTL from benign autoimmune disease. We present cases of a 10-year-old female and an 11-year-old male with SPTL showing recurrent panniculitis and systemic manifestations. Initially, antibiotics and steroids were administered to treat infectious disease and benign panniculitis. However, they experienced recurrent fever and erythema nodosum. Additional immunohistochemistry and T-cell receptor (TCR) gene rearrangement analyses were performed, enabling the establishment of an SPTL diagnosis. The affected patients were given immunosuppressive therapy with favorable results.

Cytophagic histiocytic panniculitis, hemophagocytic lymphohistiocytosis and undetermined autoimmune disorder: reconciling the puzzle

Cytophagic histiocytic panniculitis is a rare disease, associated with either nonmalignant conditions or subcutaneous panniculitis-like T-cell lymphoma, and often also associated with hemophagocytic lymphohistiocytosis (HLH). We report the case of a 11-year-old boy with a history of secondary HLH who, after a local trauma, developed a painful, indurated plaque over the right thigh associated with relapsing HLH. Histopathologic findings from skin biopsy specimens revealed significant lobular panniculitis with benign histiocytes showing hemophagocytosis. High-dose intravenous methylprednisolone and cyclosporine A treatment was highly effective. A genetic study after a new, relapsing episode of HLH revealed an heterozygous missense mutation on STX 11 gene inherited from the mother.

Pathobiology of T-cell and NK-cell lymphomas

T-cell and NK-cell lymphomas are uncommon lymphomas with an aggressive clinical course. The causes and precise cellular origins of most T-cell lymphomas are still not well defined. The WHO classification utilizes morphologic and immunophenotypic features in conjunction with clinical aspects and in some instances genetics to delineate a prognostically and therapeutically meaningful categorization. The anatomic localization of neoplastic T-cells and NK-cells parallels in part their proposed normal cellular counterparts and functions. T-cells of the adaptive immune system are mainly based in lymph nodes and peripheral blood, whereas lymphomas derived from T-cells and NK-cells of the innate immune system are mainly extranodal. This approach allows for better understanding of some of the manifestations of the T-cell and NK-cell lymphomas, including their cellular distribution, some aspects of morphology and even associated clinical findings.