Cutaneous pseudolymphomas

Dermatologic Lesions with Eosinophilia in the Head and Neck

BACKGROUND

Dermatologic lesions with notable eosinophilic infiltration of the head and neck region represent a diverse group of conditions, ranging from benign to malignant proliferations.

METHODS

We performed a comprehensive literature review focusing on head and neck dermatologic conditions that commonly present with a prominent eosinophilic infiltrate.

RESULTS

This review provides an overview of common entities showing prominent associated eosinophilic inflammatory infiltrates in this region, including epithelioid hemangioma, eosinophilic cellulitis (Wells syndrome), eosinophilic folliculitis, eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome), granuloma faciale, and Langerhans cell histiocytosis (LCH).

CONCLUSION

Eosinophils play a key role in the pathogenesis of these disorders, although the exact mechanisms remain poorly understood. Accurate diagnosis is crucial for differentiating these conditions, as they can share similar histologic features. This review aims to enhance understanding of these eosinophilic dermatologic conditions, improving diagnostic accuracy and treatment strategies.

A Rare Presentation of Amlodipine-Induced B-Cell Pseudolymphoma: Case Report and Discussion

B-cell cutaneous lymphoid hyperplasia (CLH), or B-cell pseudolymphoma, is a benign lymphoid proliferative disorder that can mimic cutaneous lymphoma. This case describes a rare instance of amlodipine-induced B-cell pseudolymphoma in a 64-year-old woman. The patient presented with itchy papules and nodules on her neck and arms, occurring shortly after starting amlodipine for hypertension. Clinical examination and punch biopsies revealed lymphoid follicles with B-cell predominance. Gene rearrangement studies were negative for clonality, supporting a benign process. The patient's reassuring clinical presentation, medication history, immunohistochemical staining and gene rearrangement analysis led to a diagnosis of B-cell CLH. Following the discontinuation of amlodipine lesions showed slow regression. Prior reports have described amlodipine-associated T-cell lymphoma but the literature lacks reports of amlodipine-induced B-cell pseudolymphoma. The diagnostic challenge lies in distinguishing pseudolymphoma from true lymphoma, emphasizing the importance of history, histopathological evaluation and clinical correlation.

Esthetic and medical tattooing: Part I: Tattooing techniques, implications, and adverse effects in healthy populations and special groups

Tattooing, the introduction of exogenous pigments into the skin, has a rich history spanning thousands of years, with cultural, cosmetic, and medical significance. With the increasing prevalence of tattoos, understanding their potential complications and contraindications is of growing importance. The most common complications are hypersensitivity reactions, which may vary in morphology and timing. Infectious complications are often due to inadequate aseptic and hygienic practices during the tattooing process or healing period. Tattoo pigment can present diagnostic challenges, affecting cancer diagnosis and imaging. This CME article explores the history, cultural significance, epidemiology, chemistry, technique, contraindications, and complications of tattoos. Appreciating these factors can help individuals considering tattoos understand the safety and potential risks of their body art, and provide physicians with a thorough understanding of tattooing if consulted.

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.

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.

Cutaneous B-Cell Pseudolymphoma (Lymphocytoma Cutis) of the Earlobe: A Poorly Recognized Complication of Ear Piercing in Children

Background: Cutaneous pseudolymphoma (CPL) refers to a group of benign, reactive processes that mimic cutaneous lymphoma and are associated with a variety of triggering immune stimuli, including arthropod bites, drugs, and foreign bodies. In children, most cases of CPL are due to a variant of Borreliosis that is specific to Eurasia. Cutaneous pseudolymphoma secondary to ear piercing has only been documented in adults. Case Reports: We present the clinical and pathological findings of cutaneous Bcell psuedolymphoma in two adolescent patients (11-year-old female and 15-year-old male) secondary to ear piercing. Conclusion: Our report expands the clinico-pathological spectrum of CPL associated with ear piercing by documenting its occurrence in children.

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.

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.

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.

Analysis of clonality in cutaneous B-cell lymphoma and B-cell pseudolymphoma using skin flow cytometry: Comparison of immunophenotyping and gene rearrangement studies

To identify clonal neoplastic cells in skin affected by B-cell lymphoma using skin flow cytometry (FCM) techniques, we investigated light-chain restriction using skin FCM with clonality assessed by polymerase chain reaction and light-chain restriction by in situ hybridization (ISH). We retrospectively analyzed 16 cases of B-cell lymphoma with cutaneous involvement: primary cutaneous diffuse large B-cell lymphoma, leg type (pcDLBCL-LT) (n = 7), DLBCL-not otherwise specified (DLBCL-NOS) (n = 6), primary cutaneous follicle center lymphoma (pcFCL) (n = 1), and follicular lymphoma (n = 2), as well as cutaneous B-cell pseudolymphoma (n = 9). Results of skin FCM light-chain restriction analyses were compared with immunoglobulin H (IgH) gene rearrangement and κ/λ ISH findings. Skin FCM detected light-chain restriction in 11 of 14 B-cell lymphoma patients but none of the B-cell pseudolymphoma patients. The sensitivity of skin FCM for distinguishing B-cell lymphoma and B-cell pseudolymphoma was 79%, and the specificity was 100%. Eleven of 13 B-cell lymphoma patients exhibited gene rearrangement (sensitivity 85%), whereas six of seven pseudolymphoma patients were negative (specificity 86%). ISH was positive in three of 16 B-cell lymphoma cases (sensitivity 19%) but none of the B-cell pseudolymphoma cases (specificity 100%). ISH sensitivity was 29% for pcDLBCL-LT, 17% for DLBCL-NOS, and 0% for pcFCL and follicular lymphoma. Skin FCM therefore appears to be more sensitive than ISH in detecting light-chain restriction in DLBCL and follicular lymphoma, and as sensitive as IgH gene rearrangement analysis in detecting clonality. Skin FCM is thus a promising diagnostic tool for identifying monoclonal neoplastic B-cell populations.

EBER in situ hybridization in subcutaneous aluminum granulomas/lymphoid hyperplasia: A diagnostic clue to differentiate injection-associated lymphoid hyperplasia from other forms of pseudolymphomas and cutaneous lymphomas

BACKGROUND

Subcutaneous vaccination or desensitization may induce persistent nodules at the injection sites. Without the knowledge of prior injection, histopathological work-up may be challenging.

OBJECTIVE

Aim of this study was to contribute to the histopathological work-up of unclear subcutaneous nodules, especially their differentiation from cutaneous lymphoma.

METHODS

We retrospectively reviewed clinical data and histopathological slides of four patients with subcutaneous nodules, which were suspected to suffer from cutaneous T- or B-cell lymphoma. Sections of these cases and 12 negative controls were stained with hematoxylin and eosin and a standardized immunohistochemical panel of B- and T-cell markers including EBER in situ hybridization as well as electron microscopy.

RESULTS

In all cases, large histiocytes with granular cytoplasm compatible with intracellular aluminum hydroxide were present. EBER in situ hybridization revealed positive staining of these granular histiocytes while staining was absent in negative controls.

LIMITATIONS

Post hoc completion of medical history revealed that vaccination or specific immunotherapy had been applied before at the biopsy site in only three out of four patients; one patient was lost to follow-up.

CONCLUSION

EBER in situ hybridization is an adjunctive tool to differentiate aluminum-induced granuloma/lymphoid hyperplasia from other forms of pseudolymphoma and cutaneous B- or T-cell lymphomas.

Inflammatory lobular hemangioma: A vascular proliferation with a prominent lymphoid component. Review of a series of 19 cases

In the last 30 years, there has been a strong interest in vascular proliferations. Pyogenic granuloma was not only renamed lobular capillary hemangioma, but also the conceptual interpretation was also changed from an overgrowth of granulation tissue to a genuine hemangioma (or benign vascular neoplasm). We describe 19 cases of patients who presented clinically with a vascular lesion, characteristically a pyogenic granuloma or lobular hemangioma, where the histopathological findings led to the pathologic concern for a lymphoma of the skin. These benign lesions with a dense lymphoid infiltrate were further defined on the basis of different vascular and lymphoid immunohistochemical markers as inflammatory lobular hemangiomas. We propose that given the considerable histopathological overlap between acral pseudolymphomatous angiokeratoma, T-cell rich angiomatoid polypoid pseudolymphoma of the skin, and other designations of some of these vascular proliferations with a rich and dense lymphoid infiltrate, they might constitute a spectrum of vascular lesions with varying clinical presentations.

A painless erythematous swelling of the external ear as a manifestation of Lyme disease: a case report

Background

Lyme disease is the most common tick-borne illness in the USA, Canada, and Europe. Clinical manifestations vary greatly, with localized skin findings functioning as early signs of the disease, followed by disseminated disease. The rarest dermatologic presentation of Lyme is a borrelial lymphocytoma, occurring distinctly in Europe and caused typically by Borrelia afzelii.

Case presentation

We report a case of a Caucasian 5-year-old European-American boy with slowly progressing, painless edema and erythema of his right pinna. Travel history revealed significant exposure to ticks during a recent trip to Eastern Europe. Laboratory testing for Borrelia burgdorferi demonstrated mixed positivity. He was treated with a 21-day course of amoxicillin, with complete resolution of symptoms and no sign of secondary Lyme disease.

Conclusions

Borrelial lymphocytoma is a rare manifestation of Lyme disease in North America, although not uncommon in Europe. Diagnosis is made by the presence of a painless erythematous swelling typically found on the ear lobe, nipples, or testes. Laboratory tests are available but with low sensitivity, therefore, a high index of suspicion is necessary for a clinical diagnosis to be made. Treatment for isolated borrelial lymphocytoma is doxycycline 4 mg/kg up to 100 mg twice daily, whereas for children less than 8 years of age amoxicillin 50 mg/kg divided three times daily, for 3–4 weeks, is preferred.

Ipilimumab/nivolumab-induced pseudolymphoma in a patient with malignant melanoma

Combination therapy with ipilimumab and nivolumab is an adjuvant treatment approach for metastatic melanoma that boasts increased 3-year survival when compared with a single immunotherapy agent. Combination therapy, however, is associated with increased toxicities, especially cutaneous side-effects. Here we present a patient with metastatic melanoma and a sudden eruption of painful nodules on the face and arms 10 days after the administration of the fourth dose of combination ipilimumab/nivolumab. Biopsies demonstrated lymphoid hyperplasia, not clinically or pathologically consistent with an infectious, malignant or autoimmune etiology; a diagnosis of pseudolymphoma secondary to ipilimumab/nivolumab was made. After a steroid taper, the lesions resolved, and the patient was restarted on nivolumab monotherapy 2 weeks later without recurrence of symptoms or disease.

Diagnostic Challenges and Treatment Options for Cutaneous T Cell Pseudolymphoma: A Case Study with Rituximab Treatment

Patient: Female, 46-year-old

Final Diagnosis: Cutaneous T cell pseudolymphoma

Symptoms: Enlarged cervical lymph nodes

Medication: —

Clinical Procedure: —

Specialty: Hematology

Cutaneous Pseudolymphoma

The term, cutaneous pseudolymphoma (PSL), refers to a group of lymphocyte-rich infiltrates, which either clinically and/or histologically simulate cutaneous lymphomas. Clinicopathologic correlation is essential to achieve the final diagnosis in cutaneous PSL and to differentiate it from cutaneous lymphomas. A wide range of causative agents (eg, Borrelia, injections, tattoo, and arthropod bite) has been described. Based on clinical and/or histologic presentation, 4 main groups of cutaneous PSL can be distinguished: (1) nodular PSL, (2) pseudo-mycosis fungoides, (3) other PSLs (representing distinct clinical entities), and (4) intravascular PSL. The article gives an overview of the clinical and histologic characteristics of cutaneous PSLs.

Progression of Cutaneous B-Cell Pseudolymphoma to Cutaneous B-Cell Lymphoma

Background:

Debates regarding nosology and clonality surround the entity known as cutaneous pseudolymphoma and its questionable transformation to frank cutaneous lymphoma. The relevance of these arguments is important, not only from a diagnostic standpoint, but also for making inferences based upon behavior, prognosis, and treatment.

Objective:

Our goal was to demonstrate further evidence of progression from cutaneous pseudolymphoma to malignant lymphoma while at the same time advocating a comprehensive plan for evaluation, treatment, and followup of these patients.

Methods:

A retrospective review was conducted of four patients initially considered to have cutaneous B-cell pseudolymphoma (CBPL) and who were later treated for primary cutaneous B-cell lymphoma (CBCL). A review of the literature of cases suggesting progression to malignant lymphoma from precursor lesions was also performed.

Results:

Four patients initially diagnosed with CBPL by a combination of histologic, immunophenotypic, and gene rearrangement criteria had a progressive clinical course that, over a range of 17–51 months, evolved into CBCL. All patients had a comprehensive systemic workup to rule out the possibility of extracutaneous disease and were treated with local radiation therapy and close followup. There has been no evidence of extracutaneous disease with an average followup of 14 months.

Conclusion:

The potential for certain cutaneous pseudolymphomas to progress to CBCL is real. The combination of histologic and immunophenotypic criteria, along with the clinical picture, remains the best way to judge the aggressiveness of the lesion. Gene rearrangement studies, whether performed by Southern blot or polymerase chain reaction (PCR), are of limited value and should be used to support the overall clinicopathologic picture. Radiation therapy of these patients should be thought of early in the management plan and is a very successful form of treatment when combined with close followup.

Disseminated induced pseudolymphoma DTP vaccine

This article considers the variant of disseminated vaccine-induced pseudolymphoma (VIP), which appeared after the introduction of the DTP vaccine. The article describes features of the observed case: common skin rashes affecting the skin of the face, left and right shoulder, chest and upper back. The effectiveness of topical corticosteroids, calcineurin inhibitors and intralesional injections of betamethasone dipropionate and betamethasone sodium phosphate solution has been shown.

Cutaneous Pseudolymphomas

The term cutaneous pseudolymphoma refers to benign reactive lymphoid proliferations in the skin that simulate cutaneous lymphomas. It is a purely descriptive term that encompasses various reactive conditions with a varied etiology, pathogenesis, clinical presentation, histology, and behavior. We present a review of the different types of cutaneous pseudolymphoma. To reach a correct diagnosis, it is necessary to contrast clinical, histologic, immunophenotypic, and molecular findings. Even with these data, in some cases only the clinical course will confirm the diagnosis, making follow-up essential.

Radiotherapy in aggressive cutaneous pseudolymphoma: a case report and review of literature

Pseudolymphoma is a nonspecific disease characterized by lesions with lymphomatous-appearing but benign accumulation of inflammatory cells. They generally present as small ulcero-nodular lesions confined to skin which often respond to local therapies. We describe an unusual presentation of an extensive and locally aggressive cutaneous pseudolymphoma in a 21-year-old male patient who presented with extensive cutaneous eruptions gradually progressing over 6 years to involve the entire circumference of his left arm. Magnetic resonance imaging scans of his left arm showed a lesion deeply infiltrating into the soft tissue reaching up to the humerus with intense periosteal reaction. He was successfully treated with radiotherapy after many failed attempts with surgery and chemotherapy.

Novel insights into the role of immune cells in skin and inducible skin-associated lymphoid tissue (iSALT)

The skin is equipped with serial barriers that provide rapid and efficient protection against external intruders. Beneath the epidermal physical barriers of the stratum corneum and the tight junctions, the integrated immune systems in both the epidermis and the dermis act in a coordinated manner to protect the host. This “immunological” barrier is composed of various cells, including skin-resident cells, such as keratinocytes, dendritic cells, tissue-resident macrophages, resident memory T cells, mast cells, and innate lymphoid cells. Additionally, infiltrating memory T cells, monocytes, neutrophils, basophils, and eosinophils are recruited in support of the host immunity.

In addition to discussing the role of each of these cellular populations, we describe the concept of skin associated lymphoid tissue (SALT), which reminds us that the skin is an important component of the lymphatic system. We further describe the newly discovered phenomenon of multiple cell gathering under skin inflammation, which can be referred to as inducible SALT (iSALT). iSALT contributes to our understanding of SALT by highlighting the importance of direct cell-cell interaction in skin immunity.

Drug-induced pseudo-Sezary syndrome: a case report and literature review

Pseudo-Sezary syndrome is a benign lymphoproliferative disorder, which clinically and pathologically mimics true Sezary syndrome. In this article, a case of pseudo-Sezary syndrome and review the literature has been reported. The patient was a 51-year-old man who developed erythroderma and palmoplantar keratoderma. The patient's medication history included fosinopril and combination metoprolol/hydrochlorothiazide. Flow cytometry showed a population of 2500 "Sezary-like" CD4726 T cells per microliter in the peripheral blood. Skin biopsy showed numerous atypical lymphocytes with epidermotropism, and there was matching dominant T-cell clonality in the skin and peripheral blood. After stopping all antihypertensive medications, the eruption resolved in its entirety.

Histopathology and immune histochemistry of red tattoo reactions. Interface dermatitis is the lead pathology, with increase in T-lymphocytes and Langerhans cells suggesting an allergic pathomechanism

BACKGROUND

The majority of tattoo reactions are affiliated to red pigmented areas and often suspected to be allergic in nature. A sizeable series of biopsies of such reactions has not previously been performed. The aim of this study was to type and grade epidermal and dermal changes in tattoo reactions to red/red nuances by microscopy and immunochemistry relevant for the assessment of a possible allergic pathomechanism.

METHODS

Skin biopsies were taken from red tattoo reactions, graded by conventional microscopy and stained for T and B-lymphocytes, Langerhans cells, macrophages and tumour necrosis factor (TNF)-α.

RESULTS

The study included 19 biopsies from 19 patients. The culprit colours were red/pink (n = 15) and purple/bordeaux (n = 4). Interface dermatitis was clearly the lead pathology found in 78% of samples, overlapped with granulomatous (in 32%) and pseudolymphomatous reaction patterns (in 32%). Epidermal hyperkeratosis (in 89%) was common as was leakage of red pigment across the dermo-epidermal junction, with transepidermal elimination (in 28%). The dermal cellular infiltration was dominated by T-lymphocytes (in 100%), Langerhans cells (in 95%) and macrophages (in 100%). TNF-α was common.

CONCLUSION

The predominant histological pattern of chronic tattoo reactions in red/red nuances is interface dermatitis. T-lymphocytes and Langerhans cells are increased suggesting an allergic pathomechanism. TNF-α may contribute to reactions. In many cases, overlapping reactive patterns were identified.

T-cell-predominant lymphoid hyperplasia in a tattoo

Cutaneous lymphoid hyperplasia (CLH) can be idiopathic or secondary to external stimuli, and is considered rare in tattoos. The infiltrate can be predominantly of B or T-cells, the latter being seldom reported in tattoos. We present a case of a predominantly T CLH, secondary to the black pigment of tattooing in a 35-year-old patient, with a dense infiltrate of small, medium and scarce large T-cells. Analysis of the rearrangement of T-cells receptor revealed a polyclonal proliferation. Since the infiltrate of CLH can simulate a T lymphoma, it is important to show that lesions from tattoos can have a predominance of T-cells.