Hypopigmented mycosis fungoides: frequent expression of a CD8+ T-cell phenotype

Paediatric cutaneous lymphomas including rare subtypes: A 40-year experience at a tertiary referral centre

BACKGROUND

Primary cutaneous lymphomas are neoplasms of the immune system with a distinct tropism for the skin and an absence of extracutaneous manifestations at the time of diagnosis. Studies focusing on cutaneous lymphomas in children and adolescents remain scarce and often do not encompass the rare subtypes.

OBJECTIVES

To address this knowledge gap by describing the clinical, histological and molecular characteristics of a large group of paediatric patients affected by primary cutaneous lymphoma. We also provided the Paediatric Primary Cutaneous Lymphoma Atlas that illustrates the clinicopathological spectrum of observed presentations, in the hope of supporting other physicians in the diagnostic process.

METHODS

Retrospective chart review of paediatric patients diagnosed with primary cutaneous lymphomas between 1980 and 2022 at the Paediatric Dermatology Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan.

RESULTS

A total of 101 patients (58 males, 43 females) met the inclusion criteria. The most common subtypes were lymphomatoid papulosis (n = 48) and mycosis fungoides (n = 31). These were followed by primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorders (n = 7), primary cutaneous anaplastic large-cell lymphomas (n = 5), primary cutaneous marginal zone B-cell lymphomas (n = 3), primary cutaneous follicle centre lymphomas (n = 2), subcutaneous panniculitis-like T-cell lymphomas (n = 2), primary cutaneous peripheral T-cell lymphoma not otherwise specified (n = 1), primary cutaneous precursor B-lymphoblastic lymphoma (n = 1) and Sézary syndrome (n = 1). Clinical follow-up data covering a median of 70.8 months (range 1-324) were available for 74 patients, of whom three died due to cutaneous lymphoma.

CONCLUSIONS

Our findings shed light on the peculiar aspects and long-term outcomes of paediatric cutaneous lymphomas, particularly emphasizing their distinctive features in comparison to their adult counterparts and exploring the less common subtypes. Further larger-scale studies are warranted to better characterize these entities and to achieve a more rapid and accurate diagnosis.

Cell adhesion molecule 1 expression in mycosis fungoides versus parapsoriasis versus inflammatory dermatosis: an immunohistochemical comparative study

Cell adhesion molecule 1 (CADM1) is one of the immunoglobulin super family adhesion molecules, that is proposed to contribute in the pathogenesis of various types of cutaneous T-cell lymphoma, including mycosis fungoides (MF). In this work, we decided to examine the immunohistochemical expression of CADM1 in MF specimens compared to premycotic parapsoriasis, benign inflammatory dermatosis and normal control skin specimens. 125 participants were enrolled (50 MF, 25 parapsoriasis, 25 inflammatory dermatosis, and 25 healthy controls). Patients were selected from the Outpatient Clinic of Dermatology and Venereology Department, Tanta University Hospitals. From all, 4 mm punch skin biopsies were taken and examined for CADM1 immunohistochemical expression. The current study revealed statistically significant upregulation of CADM1 expression in MF specimens in comparison to parapsoriasis, inflammatory dermatosis, and normal control specimens. Additionally, there was statistically significant positive correlation between CADM1 expression and progression of TNMB staging of MF disease. Therefore, it is possible to recommend CADM1 as a beneficial diagnostic immunohistochemical marker for differentiation between early stages of MF and both the premycotic parapsoriasis and benign inflammatory dermatosis. Moreover, it may be of value in early detection of neoplastic transformation of parapsoriasis as well as in assessment of MF progression.

Post-Inflammatory Hypopigmentation: Review of the Etiology, Clinical Manifestations, and Treatment Options

Post-inflammatory hypopigmentation is a common acquired pigmentary disorder that is more prominent in skin of color, leading to great cosmetic and psychosocial implications. Often, a diagnosis with a pigmentary disorder can negatively impact an individual's health-related quality of life and may result in stigma. Although most cases of post-inflammatory hypopigmentation resolve spontaneously over time, a systematic diagnostic approach can help with identifying the underlying etiology and informing treatment strategies. It can be due to cutaneous inflammation, sequelae of inflammatory or infectious dermatoses, or dermatologic procedures. Therefore, a thorough understanding of the epidemiology, patient history, physical exam findings, and clinical features of post-inflammatory hypopigmentation phenomenon can explain the primary cause to providers and allow for patient education. It is also important to understand the various therapeutic approaches available and the efficacy of these options, which will inform providers to choose the appropriate therapy for patients. Although algorithms exist for classifying acquired disorders of hypopigmentation, there are no established algorithms for the diagnosis and treatment of post-inflammatory hypopigmentation, which warrants further exploration and discourse.

Mycosis fungoides in pediatric population: comprehensive review on epidemiology, clinical presentation, and management

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma. However, it is rare in pediatric population. Most of the cases of pediatric MF present with hypopigmented patches and/or various other forms, which may often mimic common childhood dermatoses, thereby causing a delay in the diagnosis. There are no established treatment guidelines for pediatric MF. As the progression of childhood MF is extremely rare and it has an indolent course, it is usually diagnosed at an early stage (IA, IB, IIA), and hence phototherapy with a response rate of >80% is a well-established effective treatment in children. However, as recurrences are frequently seen on stopping the therapies, a maintenance regimen and long-term follow-up is equally important. This article reviews the epidemiological factors, clinical presentations, diagnosis, and various treatment modalities used in pediatric MF. We analyzed and compared the data of almost 616 childhood MF cases from various studies undertaken from 1988 to 2021.

Pediatric Mycosis Fungoides: Retrospective Analysis of a Series With CD8 + Profile and Female Predominance

BACKGROUND

Mycosis fungoides (MF) in children is a rare disease and there are limited data regarding the behavior of the disease in this age group. We aimed to collect additional data to better understand the clinicopathologic features of MF in children.

MATERIALS AND METHODS

This study was a retrospective analysis of pediatric MF patients (diagnosed at age 0 to 18 y).

RESULTS

Thirteen pediatric patients with MF were identified. Female predominance was observed with a ratio of 1.6:1. Median values for age of onset of skin lesions and age at the time of histologic diagnosis were 5 and 12 years, respectively. All patients had early stage (stage IA to IIA) of MF at the time of diagnosis. Hypopigmented MF comprised 77% of all study patients, followed by classic MF (15%) and pagetoid reticulosis (8%). The lower extremity (especially proximal leg) followed by trunk and upper extremity were most commonly affected sites. Seven of 9 patients who had available immunohistochemistry data showed CD8 + predominance. Five of 8 patients whose follow-up data was available, achieved complete response with narrowband ultraviolet B treatment, while 2 and 1 had near complete response and partial response, respectively.

CONCLUSIONS

Our study demonstrated female sex and CD8 + profile predominance. Hypopigmented MF constituted the majority of cases. We observed good responses with narrowband ultraviolet B treatment.

Hypopigmented Mycosis Fungoides: A Clinicopathological Review of 32 Patients

Background

Hypopigmented mycosis fungoides (hMF) is gradually acknowledged by more dermatologists, yet a consensus regarding its characteristics is not reached. The profile of Chinese hMF patients has not been deeply reviewed previously. Our research may contribute to the understanding of hMF, especially the Chinese patients with Fitzpatrick phototypes of III and IV.

Aim

To have a better understanding of hMF in terms of clinical, histopathological and immunohistochemical features in the Chinese population and to determine if there are differences between the Chinese population and other ethnic groups.

Methods

We made a retrospective analysis of clinical, histopathological and immunohistochemical features of 32 hMF patients in our hospital from 2010 to 2020. These features were then summarized and compared with previous reports.

Results

All patients belonged to Fitzpatrick phototypes of III or IV. Twenty-one male (65.63%) patients and 11 female (34.37%) patients were analyzed, and the male to female ratio was 1.9:1. The age at diagnosis of patients ranged from 4 to 39 years, and the average age at diagnosis of these patients was 18 years, the median age was 16.5. Back was the most frequent site (34.37%). The clinical and histological results of lesions had no distinctive points. Immunohistochemically, among these 32 patients, there were 30 patients whose information was complete, there was 19 patients (63.33%) who were CD8 positive lymphocytes predominance, 9 patients (30%) had CD8 and CD4 positive lymphocyte mixed infiltration, and other 2 patients (6.67%) had CD4 positive lymphocytes predominance. Partial loss of CD7 was only observed in 1 patient (3.33%). Nearly all patients adopted topical nitrogen mustard and topical steroid and most of them had an excellent prognosis.

Conclusion

The clinical profiles of hMF in Chinese population shared differences with other ethnic groups, but its histopathological, immunohistochemical results and prognosis condition were resembled with other previous reports. Hence, more patients were needed to find the characteristics of hMF.

Hyperpigmented mycosis fungoides: a retrospective and comparative analysis with other subtypes of mycosis fungoides

In this study, the clinicopathologic features and survival outcomes of patients with hyperpigmented MF from a single tertiary referral center database were retrospectively evaluated. Hyperpigmented MF accounted for 10.9% (14/128) of all MF cases. The mean age at diagnosis was 46.9 years, and the female-to-male ratio was 1:1.3. Concurrent hypopigmented, ichthyosiform, and poikilodermatous lesions were detected in 21.4%, 14.3%, and 14.3% of the patients, respectively. Histopathologically, most patients (85.7%) showed interface change with pigment incontinence. Double negative (CD4- and CD8-) immunophenotypes were more frequent in patients with hyperpigmented MF (25%) than in those with other MF subtypes (9.8%). Most patients (85.7%) had early-stage disease at diagnosis. The survival outcomes did not differ significantly between hyperpigmented and other MF subtypes. In conclusion, hyperpigmented MF often accompanies other atypical MF variants and is frequently associated with atypical immunophenotypes. The outcomes of hyperpigmented MF are comparable to those of other MF subtypes.

Pediatric Cutaneous Hematologic Disorders: Cutaneous Lymphoma and Leukemia Cutis: Experience of a Tertiary-Care Pediatric Institution and Review of the Literature

BACKGROUND

Cutaneous hematologic malignancies are rare in children, and the literature about them is still sparse.

OBJECTIVE

The purpose of our study was to report our experience with pediatric cases of cutaneous hematologic disorders and describe their clinical and histological features.

METHODS

Data were retrospectively collected from the histopathologic database of the CHU Sainte-Justine, University of Montreal, Montreal, Canada. All patients up to 18 years of age with a diagnosis of a primary cutaneous lymphoma (including lymphomatoid papulosis), secondary cutaneous lymphoma or cutaneous manifestations of leukemia, followed from 1980 to 2019 at our center were reviewed.

RESULTS

Thirty-six patients were included. Age at presentation ranged from birth to 18 years of age (mean 7.83 ± 5.16; median 7.0). Ten different hematologic disorders were identified according to the WHO-EORTC classifications: lymphomatoid papulosis (10 cases), mycosis fungoides (6 cases), anaplastic large cell lymphoma (4 cases), pre-B acute lymphoid leukemia (5 cases), primary cutaneous marginal zone B-cell lymphoma (4 cases), primary cutaneous CD4⁺medium T-cell lymphoproliferative disorder (1 case), extranodal NK/T-cell lymphoma (1 case), hydroa vacciniforme-like lymphoproliferative disorder (1 case), B-cell lymphoblastic lymphoma (1 case) and acute myeloid leukemia (3 cases).

CONCLUSION

The most common subtype of cutaneous hematologic disease in our single institution study was lymphomatoid papulosis (type A and type C), followed by mycosis fungoides. Recognition of this large clinical and histological spectrum by dermatologists is important because diagnosis is often established by biopsy of skin lesions, even in secondary cutaneous cases. Moreover, the clinicopathological correlation is of utmost importance for the final diagnosis of those pathologies.

Mycosis Fungoides in Children and Adolescents: A Systematic Review

Importance

Comprehensive data on childhood mycosis fungoides (MF) is scarce.

Objective

To describe clinical features, immunophenotypes, various treatment options, and prognosis of MF in children and adolescents.

Evidence Review

This systematic review searched MEDLINE via PubMed, Embase, Cochrane, and Scopus databases in October 2019. The search terms included mycosis fungoides, infant, children, and adolescent. No filter for the publication period was used, but studies written in a language other than English were excluded. Reference lists of the relevant articles were also searched manually. Case series and case reports were included if data on childhood MF were extractable. The Asan Medical Center database for cases of childhood MF was also searched. Patients were treated from January 1, 1990, to July 31, 2019, and were younger than 20 years at the time of diagnosis. The methodologic quality of the included studies was assessed with items from the Newcastle-Ottawa scale. Data were analyzed from December 9, 2019, to September 4, 2020.

Findings

A total of 571 unique patients were included. The mean (SD) age at diagnosis was 12.2 (4.2) years; at onset, 8.6 (4.2) years. The female-to-male ratio was 1:1.6 (350 male patients [61.3%]). Among 522 patients with data available at diagnosis, stage 1 disease constituted 478 cases (91.6%), followed by stage 2 (39 [7.5%]) and stage 4 (5 [1.0%]). Among the 567 patients with data available, the most common variant of MF was the hypopigmented form (309 [54.5%]), followed by classic MF (187 [33.0%]). The MF lesions were predominantly the CD4+ and CD8+ immunophenotype in 99 (49.5%) and 79 (39.5%) of 200 patients, respectively. Among the treatments, narrowband UV-B was the most frequently used (150 of 426 [35.2%]). Most patients were alive with the disease (185 of 279 [66.3%]); 83 of 279 (29.8%) were in complete remission; and 11 of 279 (3.9%) had died by the last follow-up. A longer time from onset to diagnosis (hazard ratio [HR], 1.24; 95% CI, 1.06-1.45), granulomatous slack skin (HR, 12.25; 95% CI, 1.99-75.26), granulomatous MF (HR, 14.59; 95% CI, 1.31-162.00), a history of organ transplant (HR, 10.15; 95% CI, 0.98-105.37), and stage 2 disease at the time of diagnosis (HR, 10.22; 95% CI, 2.94-35.50) were associated with worse outcomes.

Conclusions and Relevance

The findings of this review suggest that there is often a significant delay until the establishment of a correct diagnosis of childhood MF, which may be detrimental to the prognosis.

Proliferative Clonal T-Cell Infiltrate Mimicking a Cutaneous T-Cell Lymphoma Arising in Active Regression of Melanoma

ABSTRACT

Complete melanoma regression is an uncommon phenomenon involving a complex interplay of the tumor microenvironment and host immune response. We report a case of an 84-year-old woman with a history of colon and breast cancers who presented with a right forearm tumor, which was found to be a nodular melanoma; focal features of regression were noted in the biopsy. Approximately 6 weeks later, surgical resection of the site revealed no gross evidence of tumor, and histologic sections showed an extensive lymphoid infiltrate with prominent epidermotropism. Rare residual melanoma cells were present in the dermis, best visualized on immunohistochemical stains. T cells predominated in the infiltrate with an inverted CD4:CD8 ratio at approximately 1:2. There was no appreciable loss of pan[FIGURE DASH]T-cell antigens. T-cell receptor beta and gamma gene rearrangements were performed by polymerase chain reaction and demonstrated clonality in each assay. Although a synchronous cutaneous T-cell lymphoma was considered, the overall clinicopathologic features are more in line with an exaggerated host immune response leading to near complete regression of the tumor.

Comparison between the histopathological and immunophenotypical features of hypopigmented and nonhypopigmented mycosis fungoides: A retrospective study

BACKGROUND

Mycosis fungoides (MF), the commonest primary cutaneous T-cell lymphoma, has classic and variant types which include hypopigmented MF (HMF). Previous studies have identified distinct clinicopathological profiles in HMF. This study aims to objectively compare the clinicopathological features of HMF with non-HMF lesions in order to characterize salient features of HMF.

METHODS

This cross-sectional, retrospective study analyzed biopsy specimens of 87 patients with MF. HMF and non-HMF groups were compared using clinical data, immunophenotypic features and scores given for six histopathological features: dermal infiltrate, basilar and superficially extending epidermotropism, Pautrier microabscesses and dermal and epidermotropic lymphocytic atypia.

RESULTS

Seventy-six patients had HMF. Presentation in females (59.21%; p = .04) and patch stage (88.16%; p = .01) in HMF were significant, and HMF presented at a younger mean age when compared to non-HMF. Both groups had equal intensity of epidermotropism, with HMF showing milder dermal infiltrates and significantly less dermal atypia. Pautrier microabscesses were significantly commoner in non-HMF (LR 10.76; p < .01). 94.74% of HMF were CD4-/CD8+.

CONCLUSION

HMF presents at a lower age and earlier stage with female predominance compared to non-HMF. Because of milder dermal infiltrates, less dermal atypia, and Pautrier microabscesses, the diagnosis of HMF requires correlation with clinical features and careful assessment of epidermotropic cells.

Hypopigmented Mycosis Fungoides: Loss of Pigmentation Reflects Antitumor Immune Response in Young Patients

Hypopigmented mycosis fungoides (HMF) is a form of cutaneous T-cell lymphoma (CTCL), a heterogeneous group of extranodal non-Hodgkin's lymphomas. HMF has a unique set of defining features that include light colored to achromic lesions, a predilection for darker skin phototypes, an early onset of disease, and predominance of CD8⁺ T-cells, among others. In the current review, we detail the known pathways of molecular pathogenesis for this lymphoma and posit that an active Th1/cytotoxic antitumor immune response in part explains why this variant is primarily seen in children/adolescents and young adults, who do not exhibit signs of immunosenescence. As a result of this potent cytotoxic response, HMF patients experience mostly favorable overall prognosis, while hypopigmentation may in fact represent a useful surrogate marker of cytotoxic immunity targeting the malignant cells. Understanding the molecular processes behind the specific features that define HMF may lead to improved diagnostic accuracy, personalized prognosis by risk stratification, and improved management of HMF. Moreover, improving our knowledge of HMF may aid our further understanding of other cutaneous lymphomas.

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.

Epidemiological, clinical, histological, and immunohistochemical study on hypopigmented epitheliotropic T-cell dyscrasia and hypopigmented mycosis fungoides

BACKGROUND

Hypopigmented dermatoses, more evident in dark-skinned people, are a frequent cause of consultation. Their etiology includes a wide range of dermatoses, from benign to malignant diseases. The clinical presentation appears very similar between them, making the correct diagnoses and management a challenge.

METHODOLOGY

Clinical records and histopathological biopsies were identified and compared in patients of the "Dr. Manuel Gea González" General Hospital throughout a 16-year period with the presumptive diagnosis of hypopigmented epitheliotropic T-cell dyscrasia (HTCD) or hypopigmented mycosis fungoides (HMF). Immunostaining analysis was performed in each specimen, the panel of antibodies used was: CD3, CD4, CD7, CD8, CD20, and CD62L.

RESULTS

Thirty cases of 81 patients found in the registries were included in this study. The main age group was formed by children younger than 15 years old. The main clinical differences between both entities were gender, presence of plaques, and neck lesions. The most significant histopathological parameters used to differentiate both diagnoses were: severity of lymphocytic infiltration, the extent of epidermotropism, folliculotropism, presence of Pautrier's microabscesses, lymphocytes with cerebriform nuclei, and dermal fibroplasia. No immunohistochemical differences were found between them.

CONCLUSION

The clinical distinction between HTCD and HMF continues to be a challenge, therefore an extensive clinicopathological correlation must be performed. AbCD7 and AbCD62L were not useful to differentiate both dermatoses. This paper suggests that HTCD and HMF should be considered as the beginning and the end of the same clinical spectrum.

CD8+ cytotoxic mycosis fungoides: a retrospective analysis of clinical features and follow-up results of 29 patients

BACKGROUND AND OBJECTIVE

Less than 5% of cases of mycosis fungoides (MF) present with a cytotoxic/suppressor CD8⁺ phenotype. This study aimed to evaluate the clinical characteristics, treatment modalities, and clinical course in CD8⁺ MF patients.

METHODS

In a retrospective analysis of 353 MF patients in a referral center at Ankara University, Turkey, 29 patients that were diagnosed with CD8⁺ MF were included in the study.

RESULTS

CD8⁺ MF cases constituted 8.2% of all MF patients. The age at the time of diagnosis ranged between 6 and 81 years with a median value of 46 years. The female-to-male ratio was 1.41. Patients presented with erythematous scaly (69%), hyperpigmented (58.6%), poikilodermic (17.2%), and hypopigmented (17.2 %) patches/plaques. The most common sites of involvement were the trunk and lower extremities. The most common comorbidity was hypertension (24.1%, n: 7) with 13 patients (44.8%) having a history of at least one autoimmune disease. At the time of diagnosis, 93.2% of the patients had early-stage disease, and 6.8% of the patients had advanced stage. The mean follow-up period was 6.68 ± 6.04 years (range 1-28 years). Most of the patients were treated with skin-directed therapies. Complete remission was achieved in 17 (58.6%) patients, eight (27.6%) patients had partial remission, and four (13.8%) patients had stable disease.

CONCLUSIONS

We concluded that CD8⁺ MF is associated with an indolent course and in most patients, skin-directed therapies were found to be efficient to control the disease.

Outcomes and prognostic factors in African American and black patients with mycosis fungoides/Sézary syndrome: Retrospective analysis of 157 patients from a referral cancer center

BACKGROUND

The prevalence of mycosis fungoides/Sézary syndrome (MF/SS) is higher in the black population than in the white population in the United States and worse outcomes have been observed in black patients.

OBJECTIVE

To describe the outcomes and to identify prognostic factors in African American and black patients with MF/SS.

METHODS

Clinical features and follow-up data were analyzed in 157 self-identified African American or black patients seen during 1994-2018.

RESULTS

We included 122 patients with early stage MF and 35 patients with advanced-stage disease (median follow-up of 25 months). Overall, >80% of the patients who died from disease or progressed had erythema or hyperpigmentation without hypopigmentation. Patients with hypopigmentation, either as the sole manifestation or in combination with other lesions, had better overall survival (P = .002) and progression-free survival (P = .014). Clinical stage, TNMB classification, plaque disease, and elevated serum lactate dehydrogenase were also significantly associated with outcomes. Demographic and socioeconomic parameters were not associated with prognosis.

LIMITATIONS

A retrospective study at a single cancer center.

CONCLUSION

MF/SS manifestations and outcomes in African American and black patients are heterogeneous. Demographic and socioeconomic factors do not seem to have a prognostic role, while clinical characteristics might help in the stratification of risk of progression and shorter survival, allowing for individually tailored therapeutic interventions.

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.

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.

Expression of Epidermal c-Kit+ of Vitiligo Lesions Is Related to Responses to Excimer Laser

Background

The survival and growth of melanocytes are controlled by the binding of stem cell factor to its cell surface receptor c-kit+ (CD117). We have observed that c-kit+ melanocytes existed in some lesions of vitiligo, while Melan A+ cells were absent.

Objective

To verify possible relation between c-kit+ expression and treatment response in non-segmental vitiligo lesions

Methods

Skin biopsies were done from the center of the 47 lesions from the 47 patients with non-segmental vitiligo. Expression of c-kit+ and Melan A, and amounts of melanin in the epidermis were assessed in each lesion, and treatment responses to excimer laser were evaluated.

Results

Thirty-five of the 47 lesions (74.5%) had c-kit+ phenotypes. There was significant difference of c-kit staining value between good responders in 3 months of excimer laser treatment (average of 24 sessions) and the others.

Conclusion

c-Kit expression in vitiliginous epidermis may be related to better treatment responses to excimer laser.

Lymphomatoid Papulosis in Children and Adolescents: A Systematic Review

BACKGROUND

Lymphomatoid papulosis (LyP) is a lymphoproliferative disorder that is rare among adults and even rarer among children. In adults, LyP is associated with an increased risk of secondary lymphomas.

OBJECTIVE

The aim of this systematic review was to describe the clinical and histopathological features of LyP in children, to assess the risk of associated lymphomas, and to compare the disease to the adult form.

METHODS

A systematic review was conducted using the MEDLINE (PubMed), EMBASE, Scopus, and Cochrane databases from inception to June 2015. Articles were included if data were extractable from studies, case series, and single reports of pediatric LyP patients.

RESULTS

A total of 251 children and adolescents with LyP were identified, with the mean age at diagnosis being 9.3 ± 4.6 years (n = 187). The female to male ratio was 1:1.4, and the majority of children reported on were Caucasian (n = 74, 85.1 %). The predominant histologic subtype was type A (n = 106, 79.1 %). Clinically, LyP lesions presented as erythematous papules or nodules, appearing preferentially on the extremities and the trunk. LyP has to be differentiated from pityriasis lichenoides (PL) and primary cutaneous anaplastic large cell lymphoma (ALCL). PL and associated lymphomas were diagnosed before, with, and after LyP in 19 and 14 cases, respectively. Of the 14 subjects with associated lymphomas, two children developed systemic ALCL.

CONCLUSION

LyP has to be differentiated from ALCL to avoid erroneous treatments. Due to the increased risk of development of non-Hodgkin lymphomas, lifelong follow-up and proper patient counseling are warranted.

Cutaneous T-Cell Lymphoma: A Review with a Focus on Targeted Agents

Cutaneous T-cell lymphomas (CTCLs) are a heterogeneous group of extranodal lymphomas involving the skin. Diagnosis of the two main subtypes of CTCL-mycosis fungoides (MF) and Sézary syndrome (SS)-is based on the International Society for Cutaneous Lymphomas/European Organization for Research and Treatment of Cancer (ISCL/EORTC) classification system, which utilizes clinical, histopathological, molecular biologic, and immunopathologic features. Risk stratification, based on TNMB (tumor, node, metastasis, and blood) staging, provides prognostic information, with limited-stage disease conferring the longest median overall survival. Skin-directed therapies are preferred in the management of limited-stage disease, whereas advanced-stage disease requires systemic therapies. As the mechanisms of CTCL pathogenesis are increasingly understood, new monoclonal antibodies, checkpoint inhibitors, immunomodulatory agents, and small molecules are under investigation and may provide additional therapeutic options for those with advanced CTCL. This review examines the current landscape of targeted therapies in the treatment of CTCLs.

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.

Aggressive epidermotropic cutaneous CD8+ lymphoma: a cutaneous lymphoma with distinct clinical and pathological features. Report of an EORTC Cutaneous Lymphoma Task Force Workshop

AIMS

Aggressive epidermotropic cutaneous CD8(+) lymphoma is currently afforded provisional status in the WHO classification of lymphomas. An EORTC Workshop was convened to describe in detail the features of this putative neoplasm and evaluate its nosological status with respect to other cutaneous CD8(+) lymphomas.

METHODS AND RESULTS

Sixty-one CD8(+) cases were analysed at the workshop; clinical details, often with photographs, histological sections, immunohistochemical results, treatment and patient outcome were discussed and recorded. Eighteen cases had distinct features and conformed to the diagnosis of aggressive epidermotropic cutaneous CD8(+) lymphoma. The patients typically present with widespread plaques and tumours, often ulcerated and haemorrhagic, and histologically have striking pagetoid epidermotrophism. A CD8(+) /CD45RA(+) /CD45RO(-) /CD2(-) /CD5(-) /CD56(-) phenotype, with one or more cytotoxic markers, was found in seven of 18 patients, with a very similar phenotype in the remainder. The tumours seldom involve lymph nodes, but mucosal and central nervous system involvement are not uncommon. The prognosis is poor, with a median survival of 12 months. Examples of CD8(+) mycosis fungoides, lymphomatoid papulosis and Woringer-Kolopp disease presented the typical features well documented in the CD4(+) forms of those diseases.

CONCLUSIONS

Aggressive epidermotropic cutaneous CD8(+) lymphoma is a distinct lymphoma that warrants inclusion as a distinct entity in future revisions of lymphoma classifications.

Multicenter case series of indolent small/medium-sized CD8+ lymphoid proliferations with predilection for the ear and face

We report 7 cases of a CD8 lymphoid proliferation of the ear and face with a cytotoxic T-cell phenotype, but an indolent clinical course. All patients presented with stable or slowly growing asymptomatic lesions on the ear, nose, or lower eyelid. Histopathology showed a dense diffuse dermal infiltrate of small- to medium-sized atypical lymphocytes without destructive features. The lymphocytes were positive for CD3, CD8, β-F1, and TIA-1 and negative for CD4, CD30, CD56, granzyme B, and PD-1. Of note, the proliferation index was low in available cases. All patients remained in complete remission at median follow-up of 14 months regardless of treatment modality. Staging was negative for extracutaneous disease in all patients. The clinically indolent behavior and histopathologic phenotype together with a low proliferation index (10%-15%) emphasize the importance of accurate diagnosis and appropriate clinical management to avoid overtreatment and complications of therapy.

Indolent CD8+ lymphoid proliferation of the face with eyelid involvement

In 2007, Petrella et al described a series of patients with clonally restricted, well-differentiated, nonepidermotropic, CD8-dominant lymphocytic infiltrates localized to the facial area. The clinical course described was indolent. A CD8 variant of primary cutaneous pleomorphic T-cell lymphoma has been proposed; however, there are many dissimilar features. The authors encountered 2 patients with CD8⁺ indolent lymphoid proliferation of the face, localized to the eyelid. Both patients were males in their 30s presenting with localized lesions of the eyelids. The biopsies showed an effacing lymphocytic infiltrate that spanned the sampled dermis. The lymphocytes were well differentiated, exhibiting mild nuclear contour irregularity. The infiltrate was predominated by CD8⁺ lymphocytes demonstrating TIA expression. There was a minimal B-cell component in 1 case, whereas another showed a significant degree of B-cell hyperplasia. They both underwent complete excision without recurrence. CD8⁺ indolent lymphoid proliferation has a reproducible clinical and morphologic presentation that warrants categorization as a distinct form of indolent lymphoproliferative disease, preferentially involving older adults with the most common site being the ear, recognizing that the nose, acral surfaces, and eyelids can also be involved.

Mycosis Fungoides Variants

Mycosis fungoides (MF) is a cutaneous T-cell lymphoma that usually manifests as patches and plaques with a propensity for nonphotoexposed areas. MF is a common mimicker of inflammatory and infectious skin diseases, because it can be manifested with a wide variety of clinical and pathologic presentations. These atypical presentations of MF may be difficult to diagnose, requiring a high level of suspicion and careful clinicopathologic correlation. Within this array of clinical presentations, the World Health Organization classification recognizes 3 MF variants: folliculotropic MF, pagetoid reticulosis, and granulomatous slack skin. These 3 variants, as well as hypopigmented MF, are addressed in this article.

Hypopigmented mycosis fungoides: a review of its clinical features and pathophysiology

Several distinct clinical forms of mycosis fungoides have been described. Hypopigmented mycosis fungoides should be regarded as a subtype of mycosis fungoides, insofar as it presents some peculiar characteristics that contrast with the clinical features of the classical form. Most patients with hypopigmented mycosis fungoides are younger than patients typically diagnosed with classical mycosis fungoides. In addition to typical dark-skinned individuals impairment, hypopigmented mycosis fungoides has also been described in Asian patients. The prognosis for hypopigmented mycosis fungoides is much better than for classical mycosis fungoides: hypopigmented mycosis fungoides is diagnosed when there are only patches of affected skin, and lesions usually will not progress beyond terminal stages, although they can persist for many years. Diagnosis should involve clinicopathologic correlation: skin biopsy analysis often reveals intense epidermotropism, characterized by haloed, large, and atypical CD8+ lymphocytes with convoluted nuclei, in contrast to mild to moderate dermal lymphocytic infiltrate. These CD8+ cells, which participate in T helper 1-mediated immune responses, prevent evolution to mycosis fungoides plaques and tumors and could be considered the main cause of the inhibition of melanogenesis. Therefore, hypopigmentation could be considered a marker of good prognosis for mycosis fungoides.

TCR-γ expression in primary cutaneous T-cell lymphomas

Primary cutaneous γδ T-cell lymphomas (PCGD-TCLs) are considered a subgroup of aggressive cytotoxic T-cell lymphomas (CTCLs). We have taken advantage of a new, commercially available antibody that recognizes the T-cell receptor-γ (TCR-γ) subunit of the TCR in paraffin-embedded tissue. We have analyzed a series of 146 primary cutaneous T-cell lymphomas received for consultation or a second opinion in the CNIO Pathology Department. Cases were classified according to the World Health Organization 2008 classification as mycosis fungoides (MF; n=96), PCGD-TCLs (n=5), pagetoid reticulosis (n=6), CD30(+) primary cutaneous anaplastic large cell lymphomas (n=5), primary cutaneous CD8 aggressive epidermotropic CTCLs (n=3), primary cutaneous CTCL, not otherwise specified (n=4), and extranodal nasal-type NK/T-cell lymphomas primarily affecting the skin or subcutaneous tissue (n=11). Sixteen cases of the newly named lymphomatoid papulosis type D (LyP-D; n=16) were also included. In those cases positive for TCR-γ, a further panel of 13 antibodies was used for analysis, including TIA-1, granzyme B, and perforin. Clinical and follow-up data were recorded in all cases. Twelve cases (8.2%) were positive for TCR-γ, including 5 PCGD-TCLs, 2 MFs, and 5 LyP-Ds. All 5 PCGD-TCL patients and 1 MF patient died of the disease, whereas the other MF patient and all those with LyP-D were alive. All cases expressed cytotoxic markers, were frequently CD3(+)/CD8(+), and tended to lose CD5 and CD7 expressions. Eight of 12 and 5 of 11 cases were CD30(+) and CD56(+), respectively. Interestingly, 5/12 TCR-γ-positive cases also expressed TCR-BF1. All cases analyzed were negative for Epstein-Barr virus-encoded RNA. In conclusion, TCR-γ expression seems to be rare and is confined to cytotoxic primary cutaneous TCLs. Nevertheless, its expression is not exclusive to PCGD-TCLs, as TCR-γ protein can be found in other CTCLs. Moreover, its expression does not seem to be associated with bad prognosis by itself, as it can be found in cases with good and bad outcomes.

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.