The fifth edition of the WHO-Classification - what is new for cutaneous lymphomas?

The recently published 5th edition of the "World Health Organization classification of hematolymphoid tumors: lymphoid neoplasms" provides a hierarchical reorganization. In general, new (definitive) entities as well as tumor-like lesions were included. Primary cutaneous B-cell lymphomas (CBCL) received a thorough review. A new class/family of cutaneous follicle center lymphomas was defined. Primary cutaneous marginal zone lymphoma is now presented as a separate entity independent from extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. In primary cutaneous T-cell lymphoma, former provisional entities were upgraded to definite entities. Sézary Syndrome was sorted into the class/family of mature T-cell and NK-cell leukemias. Additionally, a newly formed entity of primary cutaneous peripheral T-cell lymphoma, NOS was created for CTCL entities that do not fit into the already described CTCL entities. The increasing importance of genomic and molecular data has already been recognized in classifying leukemias and systemic lymphomas. However, in PCL the genomic landscape has not yet been fully described and validated. Therefore, future research is necessary to describe the genomic and molecular mechanisms underlying the disease entities more clearly. This would both meet a diagnostic need and valuably contribute to future classification schemes.

Classifications of cutaneous lymphomas and lymphoproliferative disorders: An update from the EORTC cutaneous lymphoma histopathology group

The classification of primary cutaneous lymphomas and lymphoproliferative disorders (LPD) is continuously evolving by integrating novel clinical, pathological and molecular data. Recently two new classifications for haematological malignancies including entities of cutaneous lymphomas were proposed: the 5th edition of the WHO classification of haematolymphoid tumours and the International Consensus Classification (ICC) of mature lymphoid neoplasms. This article provides an overview of the changes introduced in these two classifications compared to the previous WHO classification. The main changes shared by both classifications include the downgrading of CD8+ acral T-cell lymphoma to CD8+ acral T-cell LPD, and the recognition of entities that were previously categorized as provisional and have now been designated as definite types including primary cutaneous small or medium CD4+ T-cell LPD, primary cutaneous gamma/delta T-cell lymphoma, primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, Epstein-Barr virus-positive mucocutaneous ulcer. Both classifications consider primary cutaneous marginal zone B-cell clonal neoplasm as an indolent disease but use a different terminology: primary cutaneous marginal zone lymphoma (WHO) and primary cutaneous marginal zone LPD (ICC). The 5th WHO classification further introduces and provides essential and desirable diagnostic criteria for each disease type and includes chapters on reactive B- or T-cell rich lymphoid proliferations formerly referred as cutaneous pseudolymphomas, as well as histiocyte and CD8 T-cell rich LPD in patients with inborn error of immunity. As already emphasized in previous lymphoma classifications, the importance of integrating clinical, histological, phenotypic and molecular features remains the crucial conceptual base for defining cutaneous (and extracutaneous) lymphomas.

A Review of Atypical Cutaneous Histological Manifestations of Herpes Zoster

The clinical and histopathological features of herpes zoster (HZ) are usually straightforward. Atypical histological presentations, in the absence of the classical viral cytopathic changes, are well documented and can make the diagnosis of HZ extremely difficult. Herein, we review the existing literature on atypical cutaneous histological manifestations of the disease, with emphasis on the subtle clues, use of immunohistochemistry, and potential pitfalls.

Role of Color Doppler Ultrasound in Cutaneous Inflammatory Conditions

Inflammatory cutaneous diseases can be challenging to diagnose and manage. Nowadays, the anatomical information provided by ultrasound is critical for detecting subclinical alterations and assessing the severity and activity of these conditions. Many of these entities can be clinically observed in dermatology and other specialties, such as rheumatology, plastic surgery, ophthalmology, and otolaryngology, among others. We review the ultrasonographic patterns of the most common inflammatory cutaneous conditions. In several cases, such as hidradenitis suppurativa, acne, and morphea, there are ultrasonographic staging systems of severity or activity that are pivotal in the management of these diseases. The early ultrasonographic diagnosis of these entities implies a proper management of the patients and, therefore, improve their quality of life. Thus, knowledge of the current use of ultrasound in this field seems essential.

Stenotrophomonas maltophilia skin infection in an immunocompetent patient: Primary cutaneous CD30+ T-cell lymphoproliferative disorder or pseudolymphoma?

Cutaneous pseudolymphomas are a wide group of diseases mimicking cutaneous lymphoma. They comprise several skin conditions with different etiopathogenesis, clinical-pathological features, and prognosis, which may occur in the absence of an identifiable trigger factor or after administration of medications or vaccinations, tattoos, infections, or arthropod bites. They present with different manifestations: from solitary to regionally clustered lesions, up to generalized distribution and, in rare cases, erythroderma. They persist variably, from weeks to years, and resolve spontaneously or after antibiotics, but may recur in some cases. CD30+ T-cell pseudolymphomas are characterized by the presence of large, activated lymphoid cells, generally in response to viral infections, arthropod assault reactions, and drug eruptions. Stenotrophomonas maltophilia is a ubiquitous Gram-negative bacillus responsible for opportunistic infections in immunocompromised patients. Infection of intact skin in immunocompetent patients is particularly rare. Here, we report a case of a man presenting an isolated nodule histopathologically mimicking a primary cutaneous CD30+ T-cell lymphoproliferative disorder.

Cutaneous Reactive Lymphoid Proliferation Arising in the Setting of Concomitant Antidepressant and Antihypertensive Therapy

Cutaneous reactive lymphoid proliferation (CRLP) is a condition that resembles cutaneous lymphoma, and differentiating the two is necessary for proper diagnosis and treatment. It can be idiopathic or caused by viruses, drugs, or skin trauma, resulting in reactive lymphoid hyperplasia. Several clinical and histopathological features are helpful for differentiating CRLP from lymphoma, and they must be considered as a whole to reach the correct diagnosis. The number, location, and progression of CRLP lesions are important clinical clues, while the type, size, arrangement, surface markers, and clonality of the cellular infiltrate are key histopathological clues. We present a case in which CRLP arose in the setting of concomitant antidepressant and antihypertensive use, which are both potential causes of CRLP. In this case, excision served as both diagnosis and treatment. The benign presentation and lack of clonality led to the diagnosis of CRLP. While the cause is unknown, drug exposure was a possible inciting factor, and the patient will be monitored for recurrence.

Pseudolymphoma on the face involving the conjunctiva

Pseudolymphoma is a benign lymphoproliferative disorder characterized by an excessive response of inflammatory cells to various triggers. To the best of our knowledge, this is the first report of pseudolymphoma occurring concurrently on the face and the conjunctiva.

The Spectrum of Cutaneous Manifestations in Lupus Erythematosus: A Comprehensive Review

Lupus erythematosus (LE) is an autoimmune inflammatory disease with complex etiology. LE may present as a systemic disorder affecting multiple organs or be limited solely to the skin. Cutaneous LE (CLE) manifests with a wide range of skin lesions divided into acute, subacute and chronic subtypes. Despite classic forms of CLE, such as malar rash or discoid LE, little-known variants may occur, for instance hypertrophic LE, chilblain LE and lupus panniculitis. There are also numerous non-specific manifestations including vascular abnormalities, alopecia, pigmentation and nail abnormalities or rheumatoid nodules. Particular cutaneous manifestations correlate with disease activity and thus have great diagnostic value. However, diversity of the clinical picture and resemblance to certain entities delay making an accurate diagnosis The aim of this review is to discuss the variety of cutaneous manifestations and indicate the clinical features of particular CLE types which facilitate differential diagnosis with other dermatoses. Although in diagnostically difficult cases histopathological examination plays a key role in the differential diagnosis of LE, quick and accurate diagnosis ensures adequate therapy implementation and high quality of life for patients. Cooperation between physicians of various specialties is therefore crucial in the management of patients with uncommon and photosensitive skin lesions.

B-cell Follicular Lymphoid Hyperplasia (Pseudolymphoma) of the Oral Cavity: A Diagnostic Quandary

Pseudolymphoma is a reactive process involving lymphadenopathy, polyclonal proliferation of B or T-cells, simulating oral lymphoma. With its incidence being very rare, only four cases have been reported in oral cavity with the detailed immunocytochemical examination, which can be due to this entity's unawareness, underdiagnosis or overdiagnosis. It is prerogative to perform immunocytochemical investigations to prevent overdiagnosis as lymphoma, which can be debilitating to the patient. Wherein the treatment of pseudolymphoma initially includes topical or intralesional corticosteroid, antibiotics to surgical and radiotherapy based on its etiology. Herein, we discuss B-cell follicular lymphoid hyperplasia previously diagnosed as small round cell tumor.

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.

Spindle Cell Lipoma With Florid Primary Follicular Lymphocytic Hyperplasia: A Novel Association With Potential Diagnostic Pitfalls

ABSTRACT

Spindle cell lipoma (SCL) is a benign subcutaneous lipomatous neoplasm with a heterogeneous histologic appearance that varies greatly depending on the amount of fat, collagen, and myxoid stroma, which define the multiple subtypes of SCL, such as fat poor SCL, pseudoangiomatous SCL, and dendritic fibromyxolipoma. Cutaneous lymphoid hyperplasia is a spectrum of benign conditions characterized by reactive B-cell and T-cell cutaneous lymphocytic infiltrates. Cutaneous B-cell lymphoid hyperplasia is a heterogeneous group of non-neoplastic conditions that can be observed as reactive phenomena to infections, medications, allergens, or neoplasms and must be distinguished from cutaneous B-cell lymphomas. Here, we report a novel case of spindle cell lipoma, associated with B-cell primary lymphoid follicular hyperplasia, mixed within the tumor in a peculiar pattern, while discussing potential diagnostic pitfalls with low-grade B-cell lymphomas. This is the first report of such association in the literature.

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.

Key Points to Select a Device for Dermatologic Ultrasound

What points to consider when selecting a device for practicing dermatologic ultrasound is an excellent question. After we met the requisites published in the guidelines for practicing dermatologic ultrasound, it is necessary to consider the main objective of the use because it is not the same to be focused mostly on the avoidance of the puncture of important facial vessels such as the case of injectors of cosmetic fillers in comparison to the use of operators that need to deal with the diagnosis and monitoring of a wide range of dermatologic pathologies. Currently, a broad variety of ultrasound devices meets the minimum requirements for practicing these examinations in the market. Thus, small, portable, and high-end devices may present advantages and limitations that must be balanced according to the primary purposes and the budget. Moreover, the shape and footprint of the probes can make difficult or facilitate a dermatologic procedure. Other points to consider are the type of storage and the need for technical service. In summary, there are key points that we need to consider when we select a dermatologic ultrasound device in dermatology or aesthetics.

Multiple and recurrent intracranial pseudolymphoma mimicking multiple skull base meningioma, a case report

INTRODUCTION AND IMPORTANCE

Primary central nervous system (CNS) lymphomas (PCNSLs) comprise a heterogeneous subset of intracranial disorders, predominantly of the intraparenchymal high-grade non-Hodgkin's lymphoma. Intracranial pseudolymphoma represents an exceedingly rare entity; as few as 3 reports in the English literature. We describe the first multiple large intracranial pseudolymphomata leading to increased intracranial pressure, visual loss, and recurrence during a short while. It also represents the first report of intracranial pseudolymphoma presented as a skull base tumor.

CASE PRESENTATION

We describe a 67-year-old female suffering from left-sided loss of visual acuity, headache, nausea, vomiting, and improper balance. Axial brain computed tomography (CT) scan revealed an isodense anterior interhemispheric mass lesion with surrounding edema in both frontal lobes. T1 and T2 weighted magnetic resonance imaging (MRI) and T1 weighted with gadolinium injection revealed two extra-axial isointense dural-based mass lesions with homogenous enhancement compressing both frontal lobes. The morphologic findings favored B cell pseudolymphoma and meningeal B cell lymphoid hyperplasia. One year later, she developed headaches, disorientation, and progressive meaningless speech lasting 2 months. Subsequent MRI demonstrated the rapid growth of the lesion of the lesser sphenoid wing and recurrence of the lesion at the same site of surgery, thereby undergoing revision surgery in which both tumors were maximally resected using a pterional approach.

CLINICAL DISCUSSION

Intracranial pseudolymphoma remains exceedingly rare, and despite its benign cellular nature, it may proliferate and recur quickly.

CONCLUSION

Intracranial pseudolymphoma should always be considered a rare but potentially differential diagnosis leading to the intraventricular lesion.

Cutaneous B-cell Pseudolymphoma: A Rare Case Masquerading a Thoracic Mass in a Fourteen-Year-Old Male Patient

Cutaneous B-cell pseudolymphoma (CBPL) may appear in the face, chest, or upper limbs, and it can be asymptomatic or in the form of nodules, papules, or masses. In most cases, it is idiopathic. However, some causes that have been identified are trauma, contact dermatitis, injected vaccinations, bacterial infections, tattoo dyes, insect bites, and certain drugs. Since the histology and clinical presentation of cutaneous pseudolymphoma (CPSL) are similar to those of cutaneous lymphomas, the diagnosis is usually based on an incisional or excisional biopsy. In this paper, a 14-year-old male patient with a two-month-old mass in the right lateral thoracic region is taken as a case study. He had neither symptoms, nor a past medical history, nor a family history. He had an insect bite a month ago and was fully vaccinated. However, the mass was some centimeters away from the insect bite. A biopsy was taken. The products of it were two paraffin cubes and two histological slides (H&E). The diagnosis was cutaneous B-cell pseudolymphoma. The total removal of the mass was decided since, in idiopathic cases like this, CBPL is not usually healed with topical and non-invasive treatments. Follow-up examinations were suggested since a further antigenic reaction is possible. If cutaneous B-pseudolymphoma is early diagnosed and treated, it does not cause serious problems. In some cases, it even resolves on its own.

Interface change in early mycosis fungoides: A potential mimicker of benign dermatoses

BACKGROUND

Histopathologic features of interface dermatitis can occasionally be seen in mycosis fungoides (MF), particularly in early patch-stage disease.

MATERIALS AND METHODS

We identified six patients with MF whose early biopsy specimens showed such prominent interface dermatitis that a benign diagnosis was favored. All subsequent specimens were reviewed for these patients, and the histopathologic evolution of disease was documented. Immunohistochemistry (IHC) for CD2, CD3, CD4, CD5, CD7, CD8, CD30, and CD123 was performed retrospectively. Educational archives were reviewed to assess the incidence of interface dermatitis in biopsies otherwise diagnostic of MF.

RESULTS

A spectrum of vacuolar and lichenoid patterns of interface change was observed in this series of six patients eventually diagnosed as having MF, and was seen as a recurring pattern in multiple specimens over time. In retrospect, findings described in early MF such as lining up of lymphocytes along the dermal-epidermal junction within the basal layer, papillary dermal fibrosis, and intraepidermal lymphocyte atypia could be appreciated to varying degrees in the confounding specimens. CD123 was negative in all cases, putatively excluding a connective tissue disease (CTD). None of the early biopsies showed loss of pan-T antigens CD2, CD5, and CD7. Forty-six of 164 cases (28%) of MF in an archival study set showed varying degrees of interface dermatitis in the setting of otherwise diagnostic changes of MF.

CONCLUSIONS

Early MF can show prominent interface change and mimic inflammatory dermatoses. Histopathologic clues suggestive of MF should be carefully assessed, and IHC for CD123 may be helpful in distinguishing MF from CTD. Repeat biopsies over time may be necessary to arrive at a definitive diagnosis, in conjunction with ancillary studies and strong clinicopathologic correlation.

Drug-induced cutaneous pseudolymphoma: A systematic review of the literature

Drug-induced cutaneous pseudolymphoma (CPL) is a common form of pseudolymphoma and there are numerous drugs associated with it. In this study, we performed a systematic review of the literature by searching PubMed/Medline and Embase databases to determine the most common drugs responsible for CPL and to define the demographic, clinical, histopathological and immunopathological characteristics of patients (updated on 30 December 2020). From 883 initially found articles, 56 studies (89 reported cases) were included. The mean age of patients was 54.4 ± 17.7 (ranging 8-86) years, and 46 (51.7%) were men. The median time interval between drug intake and CPL occurrence was 120 days (range 1-7300 days). The shortest median time interval between taking the drug and the onset of the disease was observed among patients taking antidepressants (60 days) (range 7-540) and the longest median time interval was observed in individuals using immunomodulators (300 days) (range 3-7300). The most-reported drug categories causing CPL were anti-hypertensives (17.9%), anticonvulsants (14.6%), monoclonal antibodies (13.4%) and antidepressants (11.2%). Moreover, the most common drugs were phenytoin (6.7%), amlodipine (5.6%), fluoxetine (5.6%) and carbamazepine (4.4%). Histopathological evaluation of 76 cases revealed 62 (81.5%) reports of T-cell infiltrations. Furthermore, positive reports of CD4 (94.0%), CD8 (93.0%) and CD30 (87.5%) were noted. The lowest prevalence of CD30-positive reports was observed among monoclonal antibodies. In conclusion, anti-hypertensives, anti-convulsants, monoclonal antibodies and anti-depressants are the most common drugs responsible for CPL. It mostly presents in middle-aged patients with almost no gender difference as pruritic papules, nodules and plaques.

Photodynamic Therapy as an Effective Treatment for Cutaneous Lymphomas

Topical photodynamic therapy (PDT) is a non-invasive treatment modality frequently used in dermatology to treat superficial skin cancers but also some inflammatory or infectious dermatoses. PDT appears a more and more promising therapeutic option also for cutaneous lymphomas, either of T- or B-cell origin. It is a well-tolerated treatment and has excellent cosmetic outcomes, less side effects compared to other therapies (steroids, surgery, radiotherapy, and so on), no particular contraindications, and is easily repeatable in case of relapses. However, how PDT works in the treatment of cutaneous lymphoproliferative diseases is poorly understood and the literature data are still controversial. Further randomized, controlled clinical trials involving a greater number of patients and centers with a long follow-up are necessary to assess the efficacy of PDT and establish a unique standardized treatment protocol in relation to the lymphomatous disease and the type, thickness, and location of the lesions.

Case report: Cutaneous pseudolymphoma caused by a Leishmania infantum infection in a patient treated with anti-TNF antibody for plaque psoriasis

For psoriasis, which affects up to 2% of the population and adalimumab is approved from the age of 4 years. Here, we present a middle-aged Italian man with long-term history of plaque psoriasis and psoriasis arthropathica and adalimumab therapy. He developed ulcers or nodules within the psoriatic plaques, resembling cutaneous infection with Leishmania infantum. TNF and other cytokines such as IL-12 and IFN-γ are central in the early control of the infection. Discontinuation of the anti-TNF-treatment resolved the infection without specific therapy.

New mycosis fungoides-like lymphomatoid reaction following COVID-19 vaccination: A case report

Numerous cutaneous side effects arising from COVID-19 vaccination have been reported. Mycosis fungoides (MF) is a rare indolent form of cutaneous t-cell lymphoma. While the pathogenesis of MF is not well understood, it is thought to involve immune dysregulation. There have been reports of COVID-19 vaccination induced flares and recurrences of cutaneous lymphomas and lymphomatoid reactions. We present the first reported case of COVID-19 vaccine induced MF-like lymphomatoid reaction.

Cutaneous Reactive B-cell Lymphoid Proliferations

Cutaneous lymphoid hyperplasia (CLH), also known as cutaneous pseudolymphoma, is a spectrum of benign conditions characterized by reactive B- and T-cell cutaneous lymphocytic infiltrates. B-cell lymphoid proliferations are a heterogenous group of non-neoplastic cutaneous diseases that must be histopathologically distinguished from cutaneous B-cell lymphomas. These proliferations can be observed as reactive phenomena to infections, medications, allergens, neoplasms, and more. Further, there are many inflammatory conditions that present with reactive B-cell infiltrates, including actinic prurigo, Zoon balanitis, Rosai-Dorfman, and cutaneous plasmacytosis. This review summarizes multiple cutaneous B-cell lymphoid proliferations within the major categories of reactive and disease-associated CLH. Further we discuss major discriminating features of atypical CLH and malignancy. Understanding the specific patterns of B-cell CLH is essential for the proper diagnosis and treatment of patients presenting with such lesions.

Feline and Canine Cutaneous Lymphocytosis: Reactive Process or Indolent Neoplastic Disease?

Cutaneous lymphocytosis (CL) is an uncommon and controversial lymphoproliferative disorder described in dogs and cats. CL is generally characterized by a heterogeneous clinical presentation and histological features that may overlap with epitheliotropic lymphoma. Therefore, its neoplastic or reactive nature is still debated. Here, we describe clinicopathological, immunohistochemical, and clonality features of a retrospective case series of 19 cats and 10 dogs with lesions histologically compatible with CL. In both species, alopecia, erythema, and scales were the most frequent clinical signs. Histologically, a dermal infiltrate of small to medium-sized lymphocytes, occasionally extending to the subcutis, was always identified. Conversely, when present, epitheliotropism was generally mild. In cats, the infiltrate was consistently CD3+; in dogs, a mixture of CD3+ and CD20+ lymphocytes was observed only in 4 cases. The infiltrate was polyclonal in all cats, while BCR and TCR clonal rearrangements were identified in dogs. Overall, cats had a long-term survival (median overall survival = 1080 days) regardless of the treatment received, while dogs showed a shorter and variable clinical course, with no evident associations with clinicopathological features. In conclusion, our results support a reactive nature of the disease in cats, associated with prolonged survival; despite a similar histological picture, canine CL is associated with a more heterogeneous lymphocytic infiltrate, clonality results, and response to treatment, implying a more challenging discrimination between CL and CEL in this species. A complete diagnostic workup and detailed follow-up information on a higher number of cases is warrant for dogs.

Cutaneous Pseudolymphoma With Langerhans Cell Hyperplasia-A Rare Case With Clinical Presentation Mimicking Malignancy and Potential Diagnostic Pitfall

ABSTRACT

We describe a rare case of cutaneous pseudolymphoma with Langerhans cell hyperplasia. An 84-year-old female patient presented with erythematous and pernicious-looking plaques on her scalp that had been present for months. Histologically, lymphoid follicles consisting of mixed-type lymphocytes and Langerhans cells were aggregated focally. The diagnosis was verified by several immunohistochemical stains and by clinical evaluation. Skin lesions were steadily resolved with low-dose corticosteroid and hydroxychloroquine.

Dermatoscopy of nodular/plaque-type primary cutaneous T- and B-cell lymphomas: A retrospective comparative study with pseudolymphomas and tumoral/inflammatory mimickers by the International Dermoscopy Society

BACKGROUND

Limited data on dermatoscopy of nodular/plaque-type T-/B-cell primary cutaneous lymphomas (PCLs) is available.

OBJECTIVE

To describe dermatoscopic features of nodular/plaque-type PCLs, comparing them with those of clinical mimickers (pseudolymphomas, tumors, and inflammatory lesions) and investigating possible differences according to histologic subtypes.

METHODS

Participants were invited to join this retrospective, multicenter case-control study by submitting histologically/immunohistochemically confirmed instances of nodular/plaque-type PCLs and controls. Standardized assessments of the dermatoscopic images and comparative analyses were performed.

RESULTS

A total of 261 lesions were included (121 PCLs and 140 controls). Orange structureless areas were the strongest PCL dermatoscopic predictor on multivariate analysis compared with tumors and noninfiltrative inflammatory dermatoses. On the other hand, a positive association was found between PCLs and either unfocused linear vessels with branches or focal white structureless areas compared with infiltrative inflammatory dermatoses, whereas white lines were predictive of PCLs over pseudolymphomas. Differences in the vascular pattern were also seen between B- and T-cell PCLs and among B-cell PCL subtypes.

LIMITATIONS

Retrospective design and the lack of a dermatoscopic-pathologic correlation analysis.

CONCLUSION

Nodular/plaque-type PCLs display dermatoscopic clues, which may partially vary according to histologic subtype and whose diagnostic relevance depends on the considered clinical differential diagnoses.

Cutaneous Lymphoid Hyperplasia With T-Cell Clonality and Monotypic Plasma Cells Secondary to a Tick Bite: A Hidden Critter and the Power of Deeper Levels

Cutaneous lymphoid hyperplasia (CLH) is a benign reactive process with T-cell or B-cell lymphocytic infiltration in the skin, which can simulate cutaneous lymphomas both clinically and histologically. Various antigenic stimuli have been implicated in the development of CLH, including tick bites. Finding histologic evidence of such triggering factors, however, is often difficult. Moreover, the presence of clonality in CLH can potentially be interpreted as a neoplastic process, posing a further diagnostic challenge to dermatopathologists, if one is not aware of such peculiar phenomena. Herein, we describe a case of CLH secondary to a tick bite, featuring both T-cell clonality and monotypic plasma cells with lambda light chain restriction; the diagnostic clue being tick parts, which became evident on assessment of deeper levels. To the best of our knowledge, this is the first reported case of a tick-associated clonal CLH with simultaneous detection of monoclonal T cells and monotypic lambda light chain restriction, mimicking primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder and Borrelia-associated primary cutaneous marginal zone B-cell lymphoma, respectively.

Lymphocytoma cutis (cutaneous B-cell pseudolymphoma): study of 102 cases with emphasis on the histological characteristics and immunohistochemistry of the miliarial type

BACKGROUND

Lymphocytoma cutis (LC) is a benign reactive lymphoproliferative B-cell process. It has two variants: localized type with solitary lesions and miliarial type with numerous lesions. The objective was to investigate the characteristics of LC with emphasis on the miliarial type.

METHODS

Retrospective study, patients with clinical and histopathological diagnosis of LC were included. Age, sex, evolution time, affected site, and type of treatment were investigated. In miliarial-type LC, the histological and immunohistochemical characteristics were also investigated.

RESULTS

In an 18-year period, there were 102 patients found with LC: 72 (71%) corresponded to females, the median age was 45 years, the median evolution time was 4 months, and the face was the most predominant affected area in 81 (79%) cases. Localized-type LC corresponded to 88 (86%) cases, and miliarial type in 14 (14%). The most common treatment was surgery, which was used in 32 (31%) patients, all of whom had localized type (P < 0.01). The most frequent treatment for miliarial-type LC was corticosteroids in five (36%, P = 0.32), the predominant histopathological pattern was nodular in 10 (71%) specimens, and immunohistochemistry was performed in 11 (79%), where all were positive for CD20 with polyclonality to kappa and lambda light chains.

CONCLUSIONS

The importance of LC lies in that it can be clinically and histopathologically confused with cutaneous lymphoma and that it is a rare entity, with its miliarial variant being rarer still. This study provides information on the clinical-histological characteristics of LC and its immunohistochemistry.

T-cell pseudolymphoma secondary to ixazomib for multiple myeloma

We present a case of a 54‐year‐old male with multiple myeloma (MM) who presented with widespread pruritic erythematous lesions following ixazomib treatment. This occurred after his third cycle of treatment with ixazomib, thalidomide and dexamethasone and was controlled by potent steroids and temporary cessation of ixazomib. The strong correlation between the timeline of the rash, ixazomib treatment and subsequent cessation led to a diagnosis of a drug‐induced rash. Skin biopsy histology, immunochemistry and the absence of monoclonal T‐cell receptor gene rearrangement further confirmed the diagnosis of a T‐cell pseudolymphoma secondary to ixazomib. Ixazomib is an oral proteasome inhibitor used in the treatment of MM. Other proteasome inhibitors have been reported to trigger cutaneous adverse effects. However, to our knowledge, this is the first report of pseudolymphoma following proteasome inhibitor use. Dermatologists should be aware of this potential effect and the possible management pathways such as cessation and dose reduction.

Ultrasonography of cutaneous nodular pseudolymphoma at 18 and 71 MHz

Cutaneous pseudolymphomas are reactive lymphoproliferations. The most frequent type is nodular pseudolymphoma, and to date, their ultrasonographic appearance has not been reported. We reviewed the ultrasound images of histologically confirmed nodular types of pseudolymphomas studied with 18 and 71 MHz linear probes. All lesions were predominantly hypoechoic and presented prominent vascularity. Seventy percent of cases involved dermis and hypodermis, and 30% were only dermal. Seventy percent of cases showed internal hypoechoic globules, and 100% presented a teardrop sign, more clearly detected at 71 MHz. Ultrasound can support the diagnosis, assessment of the extent, and degree of vascularity of cutaneous nodular pseudolymphomas.

Clinical and Dermoscopic Features of a Case of Idiopathic T-Cell Pseudolymphoma

Cutaneous pseudolymphomas are a group of benign lymphocyte-rich infiltrates that can mimic cutaneous lymphomas either clinically and/or histologically. Idiopathic T-cell pseudolymphoma (TCPL) usually presents as a solitary nodule or plaque on the trunk or head. A clinicopathologic correlation is mandatory to arrive at a final diagnosis and rule out true lymphomas. There are only sparse dermoscopic reports on cutaneous pseudolymphomas. Hereby, we describe the clinical and dermoscopic features of a case of idiopathic TCPL in a 26-year-old man who presented with an asymptomatic thin reddish-brown "table tennis racquet"-shaped plaque on the right inframammary area.

Pseudomalignancies in Children: Histological Clues, and Pitfalls to Be Avoided

The term “pseudomalignancy” covers a large, heterogenous group of diseases characterized by a benign cellular proliferation, hyperplasia, or infiltrate that resembles a true malignancy clinically or histologically. Here, we (i) provide a non-exhaustive review of several inflammatory skin diseases and benign skin proliferations that can mimic a malignant neoplasm in children, (ii) give pathologists some helpful clues to guide their diagnosis, and (iii) highlight pitfalls to be avoided. The observation of clinical–pathological correlations is often important in this situation and can sometimes be the only means (along with careful monitoring of the disease’s clinical course) of reaching a firm diagnosis.