Pityriasis lichenoides: a cytotoxic T-cell-mediated skin disorder. Evidence of human parvovirus B19 DNA in nine cases

Pityriasis Lichenoides Chronica of Esophagus: A Rare Case Report

Pityriasis lichenoides chronica (PLC) is an uncommon inflammatory skin condition of unknown cause that ranges from a mild chronic form to a more severe acute eruption. Both forms usually involve the skin of the trunk and proximal extremities, and visceral involvement is not a well-described phenomenon. Here, we report a case of PLC that presented with esophageal involvement that occurred after a period of discontinuation of PLC treatment. The histological pattern of involvement is in the form of lymphocytic esophagitis, a non-specific pattern with a broad differential diagnosis. Awareness of the potential involvement of the esophagus and attention to certain endoscopic and morphological details may better help classify esophagitis biopsies and the diagnosis of this rare non-neoplastic chronic inflammatory disease. To our knowledge, this is the first-ever case of PLC with esophageal involvement, and nothing has been reported in the English literature earlier.

Type D lymphomatoid papulosis with pityriasis lichenoides et varioliformis acuta-like features in a child with parvovirus infection: a controversial diagnosis in the spectrum of lymphoid proliferations: case report and literature review

Background

Lymphomatoid papulosis (LyP) is a rare condition in pediatrics; LyP histological type D has been reported in only 7 children. The differential diagnosis of LyP in the spectrum of lymphoid proliferation remains controversial.

Case presentation

A 6-year-old boy presented to Emergency Department with a 3-week history of an erythematous papulo-vesicular itchy eruption over the submandibular regions, trunk and extremities. History, symptoms and laboratory tests were unremarkable. SARS-CoV-2 antigen was negative. The clinical suspicion of pityriasis lichenoides et varioliformis acuta (PLEVA) was posed, and topical steroids were introduced. One week after, he returned with an extensive painful scaly papulo-erythematous rash, with some ulcerated and necrotic lesions, and fever; therefore the child was hospitalized. Biochemical results were within reference limits, except for high level of C-reactive protein, aspartate aminotransferase, alanine transaminase and bilirubin. Due to a persistently high fever, systemic corticosteroid treatment was administered, with a good clinical response and an improvement of the skin lesions. Anti-PVB-19 Immunoglobulin M was detected. Elevated levels of IL-6, IL-10 and IFN-γ were also recorded. Five days post-admission, most of the lesions had cleared, and the child was discharged. Methotrexate was started, with a positive response. At skin biopsy a “PLEVA-like” pattern was apparent, with a dense, wedge shaped lymphoid infiltrate featuring epidermotropism and morphologically comprising pleomorphic and blastic cells. The pattern of infiltration was highlighted by immunohistochemical stains, which prove the process to feature a CD8+/CD30 + phenotype, the latter being intense on larger cells, with antigenic loss. Polymerase chain reaction for T-cell receptor gamma (TCRG) chain clonality assessment documented a monoclonal peak. A diagnosis of LyP type D was favored.

Conclusion

The reported case encompasses most of the critical features of two separated entities—PLEVA and LyP—thus providing further support to the concept of them representing declinations within a sole spectrum of disease. Studying the role of infectious agents as trigger potential in lymphoproliferative cutaneous disorders and detecting novel markers of disease, such as cytokines, could have a crucial impact on pathogenic disease mechanisms and perspective therapies.

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.

Papulo-purpuric dermatitis of childhood: a distinct PLEVA-like eruption associated to SARS-CoV-2 infection. Clinical, histopathological and immunohistochemical study of 10 cases

We observed ten children with a papular eruption with purpuric features during the SARS-CoV-2 pandemic in Northern Italy (May-December 2020). Histological examination showed signs of SARS-CoV-2-related dermatosis. Evidence of nucleocapsid viral proteins using SARS-CoV-2 (2019-nCoV) nucleocapsid antibody revealed cuticular staining of the deep portion of the eccrine glands in all cases.

Pityriasis Lichenoides: A Large Histopathological Case Series With a Focus on Adnexotropism

INTRODUCTION

Pityriasis lichenoides (PL) is an infrequent skin disorder. The clinical manifestations are usually specific enough for a reliable diagnosis, although the histopathological assessment of a biopsy is sometimes needed to differentiate between PL and a range of other diseases. The objectives of this study were to review cases of PL managed in our hospital, confirm the classical histopathological features of PL, and identify signs that may be of value in the diagnosis of PL.

MATERIALS AND METHODS

All cases of PL assessed in our pathology department between January 2007 and December 2017 were retrieved, and all slides were reviewed. Cases were selected only if a diagnosis of PL was initially suggested by a dermatologist and then confirmed by the histopathological assessment.

RESULTS

Seventy-one cases met the study criteria. The following features were almost always present: vacuolar changes or necrotic keratinocytes (100%), both superficial and deep lymphocytic infiltrates (99%), and the infiltration of lymphocytes into the adnexal epithelium (97%). The inflammatory cells were always small- to medium-sized lymphocytes. There were no eosinophilic infiltrates. Superficial perivascular and/or intraepidermal red blood cells were observed in 83% of cases.

DISCUSSION

We highlighted the presence of a deep dermal lymphocytic infiltrate, with a "T-shaped" periadnexal arrangement along the full length of the follicular and sudoral epithelia. This might be a feature that enables the differentiation of PL from other diseases. Our findings also prompted a number of physiopathological hypotheses for PL.

CONCLUSIONS

Our present results confirmed the classical histological aspects of PL and provided some useful new diagnostic features.

Histopathology of Cutaneous Inflammatory Disorders in Children

Inflammatory dermatoses encompass a variety of histologic patterns that affect different portions of the skin. In spongiotic, psoriasiform, lichenoid, pityriasiform, and blistering disorders, there are predominately epidermal and junctional activities with variable superficial dermal inflammation. Hypersensitivity reactions can show either epidermal or mostly dermal changes depending on whether the exposure of the exogenous allergen occurs through an external or internal route, respectively. Exceptions include erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis, where the etiology is often due to infection or ingested medications, but the histologic features are almost exclusively confined to the epidermis and dermoepidermal junction. Autoimmune disorders are unique in that lesions typically incorporate a mixture of epidermal and dermal inflammatory patterns with periadnexal inflammation, while the vast majority of vasculitis/vasculopathy and alopecia have changes limited to only the vessels and hair follicles, respectively. It is critical to recognize that a relatively limited number of histologic patterns are seen in a large array of clinical entities. Therefore, clinicopathologic correlation and careful examination of histologic details are of the utmost importance when evaluating skin biopsies for inflammatory disorders.

Pityriasis Lichenoides in Childhood: Review of Clinical Presentation and Treatment Options

Pityriasis lichenoides (PL) is a skin condition of unclear etiology that occurs not uncommonly in childhood. It is often classified into the acute form, pityriasis lichenoides et varioliformis acuta (PLEVA), and the chronic form, pityriasis lichenoides chronica (PLC). We performed a comprehensive review of the English-language literature using the PubMed database of all cases of childhood PL reported from 1962 to 2014 and summarized the epidemiology, clinical features, treatment options, and prognosis of this condition in children. The proposed etiologies are discussed, including its association with infectious agents, medications, and immunizations and evidence for PL as a lymphoproliferative disorder. We found an average age of PL onset of 6.5 years, with a slight (61%) male predominance. We also found that PLEVA and PLC tend to occur with equal frequency and that, in many cases, there is clinical and histopathologic overlap between the two phenotypes. When systemic therapy is indicated, we propose that oral erythromycin and narrowband ultraviolet B phototherapy should be first-line treatment options for children with PL since they have been shown to be effective and well tolerated. In most cases, PL follows a benign course with no greater risk of cutaneous T-cell lymphoma, although given the rare case reports of transformation, long-term follow-up of these patients is recommended.

Febrile ulceronecrotic Mucha-Habermann disease

The Mucha-Habermann disease is an inflammatory disease of the skin and is a variant of pityriasis lichenoides et varioliformis acuta. We describe the case of a 64-years-old woman who was admitted for erysipelas of the face. Despite treatment, evolution was marked by the appearance of a necrotising ulcerative area in the centre of the erysipelas associated with local oedema and headache. A skin biopsy revealed a pityriasis lichenoides et varioliformis acuta. Corticosteroids led to a rapid stabilisation of lesions, and after 6 months the patient shows only a small area of frontal hypopigmentation. The aetiology remains uncertain. There is no established standard treatment. We would like to draw attention of the medical and surgical specialists to this rare disease. The diagnosis should be considered in a necrotic lesion associated with rapid expansion of systemic and peripheral cutaneous signs. Diagnosis must be considered to avoid unnecessary debridement and extensive scars.

Pityriasis lichenoides chronica associated with herpes simplex virus type 2

Introduction. Pityriasis lichenoides is a rare, acquired spectrum of skin conditions of an unknown etiology. Case Report. A 28-year-old man presented with recurrent outbreaks of herpes simplex virus associated with the onset of red-to-brown maculopapules located predominantly in trunk in each recurrence. Positive serologies to herpes simplex virus type 2 were detected. Histopathological examination of one of the lesions was consistent with a diagnosis of pityriasis lichenoides chronica. Discussion. Pityriasis lichenoides is a rare cutaneous entity of an unknown cause which includes different clinical presentations. A number of infectious agents have been implicated based on the clustering of multiple outbreaks and elevated serum titers to specific pathogens (human immunodeficiency virus, cytomegalovirus, Epstein-Barr virus, Toxoplasma gondii, and herpes simplex virus). In our patient, resolution of cutaneous lesions coincided with the administration of antiviral drugs and clinical improvement in each genital herpes recurrence. In conclusion, we report a case in which cutaneous lesions of pityriasis lichenoides chronica and a herpes simplex virus-type 2-mediated disease have evolved concomitantly.

Childhood pityriasis lichenoides and oral erythromycin

Pityriasis lichenoides (PL) is not uncommon in childhood, but current knowledge about the efficacy of oral erythromycin therapy for its treatment in children is limited. To investigate the role of oral erythromycin therapy in the treatment of PL in children, the records of 24 children with PL who had been started on oral erythromycin treatment at our institution between 2005 and 2008 were retrospectively reviewed. The study included 24 patients (14 male, 10 female) with a median age of 7 years (range 2-14) of whom 15 (62.5%) had PL chronica (PLC), six (25%) PL et varioliformis acuta (PLEVA), and three (2.5%) PLEVA-PLC overlap. History of upper respiratory tract infection was reported in 33% (n = 8) of the patients. History of drug intake and vaccination was noted in 20% (n = 5) and 20% (n = 5), respectively. The disease began during spring (30%, n = 7) or fall (30%, n = 7) in the majority of patients. The median duration of the disease was 11 months (range 1-48 months). Fifteen (68.2%) patients had more than 100 lesions. Distribution was diffuse in 82% (n = 18) of the cases and peripheral in the remainder (n = 6). Oral erythromycin was started at a dosage of 30 to 50 mg/kg per day in three to four divided dosages for 1 to 4 months. Good response was recorded in 64% and 73% of patients in the first and second months of therapy, respectively. Response rate rose to 83% in the third month. In those for whom follow-up data were available (n = 16), relapse was recorded in 12.5% (n = 3). Oral erythromycin may be an effective and well-tolerated treatment option for PL in children and should be continued for at least 3 months.

Clonality in sarcoidosis, granuloma annulare, and granulomatous mycosis fungoides

The histological discrimination of granulomatous cutaneous T-cell lymphomas (CTCLs) from reactive granulomatous disorders such as sarcoidosis and granuloma annulare (GA) may be difficult due to overlapping histological features. We analyzed the T-cell receptor gene rearrangement in sarcoidosis and GA to investigate the value of the detection of clonal T cells as an adjunctive diagnostic marker in the differentiation between sarcoidosis and GA versus granulomatous CTCLs. Rearrangement of T-cell receptor γ genes was examined by the use of automated high-resolution polymerase chain reaction fragment analysis in 35 cases of sarcoidosis and 15 cases of GA and compared with a series of 19 cases of granulomatous CTCLs. A monoclonal T-cell population was found in none of the cases of sarcoidosis and in 2 of 15 cases of GA (13%). In granulomatous CTCLs, a neoplastic T-cell clone was detected in 94%. Presence of clonal T cells argues in favour of a granulomatous CTCL, while a polyclonal T-cell population makes the presence of a sarcoidosis or a GA more likely. The analysis of T-cell clonality is a useful diagnostic adjunct in the differentiation between sarcoidosis and GA from granulomatous CTCLs.

Febrile ulceronecrotic Mucha-Habermann's disease with pulmonary involvement

We report a case of febrile ulceronecrotic Mucha-Habermann disease (FUMHD) in a 12-year-old boy. After 1 week of typical cutaneous appearance of pityriasis lichenoides et varioliformis acuta (PLEVA), he was given a percutaneous injection of measles virus vaccine, and then extensive polymorphous, papular, and ulcerohemorrhagic skin lesions developed along with intermittent high temperature, hepatic dysfunction, and hypoalbuminemia. Thoracic CT scan showed parenchymal nodular infiltration at the tip of vascular structures. Skin biopsy showed a combination of the classic features of PLEVA and an allergic vasculitis. We treated him with prednisolone and methotrexate (MTX) successfully. The evolution in our patient suggests that FUMHD may have been triggered by virus vaccination. We also emphasize that FUMHD in children may be successfully treated with a combination of systemic MTX and high-dose corticosteroids.

Immunocytochemistry and the diagnosis of cutaneous lymphoma

Cutaneous lymphoid infiltrates may pose some of the most difficult diagnostic problems in dermatopathology. Immunocytochemistry is often employed in an effort to determine whether an infiltrate is neoplastic or, in the case of clearly malignant infiltrates, to provide a specific diagnosis. The rarity of these disorders and the variant immunocytochemical profiles they may present further thwart understanding and sometimes prevent an accurate diagnosis. In this review the common immunocytochemical profiles of various cutaneous lymphomas are presented and potential pitfalls and problems considered. Immunocytochemistry is not a diagnostic test but, as in other areas of histopathology, is a highly valuable tool that requires critical interpretation within a context: so applied, it is an indispensable part of the pathologist's arsenal in evaluating lymphoid infiltrates and defining different lymphomas.

Pityriasis lichenoides: the differences between children and adults

BACKGROUND

Pityriasis lichenoides (PL) is a skin disease that affects both children and adults. Anecdotally, it is said to run a more benign course in children, with a frequent tendency to self-resolution. However, to our knowledge, there have been no published studies comparing PL in both age groups.

OBJECTIVE

To evaluate the clinicopathological features, overall efficacy of treatments and disease outcomes in children and adults diagnosed with PL.

METHODS

A retrospective review of records was undertaken on all patients diagnosed with PL at two regional centres during an 8-year period (from 1998 to 2006). For each individual, data were collected on age, sex, number of lesions, lesional morphology and distribution, symptoms, histopathological features, treatment modalities (and response), overall follow-up and length of remission.

RESULTS

We recorded 25 children (median age 8 years, range 2-18) and 32 adults (median age 40 years, range 20-65) with PL. All the children and adults had more than 20 scaly, papular lesions. Children had greater lesional body involvement than adults. Lesions on the legs and trunk were present in 23 children (92%) compared with 19 adults (59%) (P < 0.01) and facial involvement was observed more commonly in children (n = 10, 40%) compared with adults (n = 8, 25%). Dyspigmentation was significantly more common in children (n = 18, 72%) compared with adults (n = 6, 19%) (P < 0.001). Topical corticosteroids were used by 16 children (64%) and 18 adults (56%) but only half in each group found these effective. Eight children (32%) were treated with erythromycin, with only two (25%) clearing, and one of these subsequently relapsing. In contrast, four adults (13%) received antibiotics, with three (75%) clearing and none relapsing thereafter. Ultraviolet B phototherapy was used in eight children (32%), with seven (88%) completely or almost clearing, but four (57%) subsequently relapsed. Fourteen adults (44%) received phototherapy; 10 (71%) completely cleared and only two of these (20%) subsequently relapsed. Strikingly, after a median disease duration of 30 months, only five children (20%) went into complete remission compared with 25 adults (78%) (P < 0.001).

CONCLUSIONS

This is the first study to compare PL in children and adults. Our findings suggest that, compared with adults, PL in children is more likely to run an unremitting course, with greater lesional distribution, more dyspigmentation and a poorer response to conventional treatment modalities.

Role of bromelain in the treatment of patients with pityriasis lichenoides chronica

OBJECTIVES

Pityriasis lichenoides chronica (PLC) is a skin disease of unknown etiology. Uncertainty about the etiopathogenesis of this skin disease is the reason for the unpredictable and non optimal efficacy of therapies available for its treatment. The aim of the present study was to evaluate the efficacy of bromelain, a crude aqueous extract of the stems and immature fruit of pineapple, in the treatment of PLC.

MATERIALS AND METHODS

Eight patients (3 males and 5 females) with PLC were enrolled in the study and treated for three months with oral bromelain (40 mg 3 times a day for 1 month, 40 mg twice a day for 1 month and 40 mg/day for 1 month).

RESULTS

All patients showed complete clinical recovery after treatment. In 12 months of follow up, two patients experienced relapse 5-6 months after suspension of therapy but responded to another brief cycle of therapy. No side effects were encountered during therapy.

CONCLUSIONS

In conclusion bromelain can be considered an effective therapeutic option for PLC; its efficacy could be related to its anti-inflammatory, immunomodulatory and/or anti-viral properties.

Pediatric pityriasis lichenoides and cutaneous T-cell lymphoma

PURPOSE OF REVIEW

The purpose of this review is to educate the reader about two cutaneous lymphoproliferative diseases in childhood: pityriasis lichenoides and cutaneous T-cell lymphoma. Pityriasis lichenoides has traditionally been divided into acute and chronic subtypes. The two forms of the disease, however, are best thought of as two ends of a benign lymphoproliferative spectrum. Cutaneous T-cell lymphoma is a rare but underrecognized cutaneous malignancy in children. Early stage disease and hypopigmented presentation are characteristic of pediatric cutaneous T-cell lymphoma. The optimal investigation and treatment plans are still controversial.

RECENT FINDINGS

This article will summarize recent articles on pityriasis lichenoides and pediatric cutaneous T-cell lymphoma, including recent findings from an international registry of pediatric cutaneous T-cell lymphoma.

SUMMARY

After reading this review, the reader should be able to recognize the clinical presentation of pityriasis lichenoides, to understand the overlap between its acute and chronic forms, and to recognize its relationship with cutaneous T-cell lymphoma. In addition, the reader will appreciate the challenges in diagnosing and treating pediatric cutaneous T-cell lymphoma.

Local and Circulating Microchimerism Is Associated with Hypersensitivity Pneumonitis

RATIONALE

Hypersensitivity pneumonitis (HP) is a lymphocytic alveolitis provoked by exposure to a variety of antigens. However, the disease occurs in only a subset of exposed individuals, suggesting that additional factors may be involved. Microchimerism has been implicated in the pathogenesis of autoimmune diseases, especially in those showing increased incidence after childbearing age.

OBJECTIVES

To evaluate the presence of circulating and local microchimeric cells in female patients with HP.

METHODS

Male microchimerism was examined in 103 patients with HP, 30 with idiopathic pulmonary fibrosis (IPF), and 43 healthy women. All of them had given birth to at least one son, with no twin siblings, blood transfusions, or transplants. Microchimerism was examined by dot blot hybridization (peripheral blood), and by fluorescence in situ hybridization in bronchoalveolar lavage cells and lungs.

MEASUREMENTS AND MAIN RESULTS

Blood microchimerism was found in 33% of the patients with HP in comparison with 10% in those with IPF (p = 0.019) and 16% in healthy women (p = 0.045). Patients with HP with microchimerism showed a significant reduction of diffusing capacity of carbon monoxide (Dl(CO); 53.5 +/- 11.9% vs. 65.2 +/- 19.7%; p = 0.02) compared with patients with HP without microchimerism. In bronchoalveolar lavage cells, microchimerism was detected in 9 of 14 patients with HP compared with 2 of 10 patients with IPF (p = 0.047). Cell sorting revealed that microchimeric cells were either macrophages or CD4+ or CD8+ T cells. Male microchimeric cells were also found in the five HP lungs examined by fluorescence in situ hybridization.

CONCLUSIONS

Our findings (1) demonstrate that patients with HP exhibit increased frequency of fetal microchimerism, (2) confirm the multilineage capacity of microchimeric cells, and (3) suggest that microchimeric cells may increase the severity of the disease.

Pityriasis lichenoides in childhood: A retrospective review of 124 patients

BACKGROUND

Pityriasis lichenoides (PL) occurs in all age groups, although predominantly in younger individuals.

OBJECTIVE

We sought to study the clinical features of PL in children followed up at our institution.

METHODS

The records of 124 children who were given the diagnosis of PL at our institution between 1993 and 2003 were retrospectively reviewed.

RESULTS

PL chronica (PLC) was recorded in 37% of the cases, PL et varioliformis acuta (PLEVA) in 57.3%, and clinical features of both disorders were seen simultaneously in the remaining. The median age of onset was 60 months (range: 6-180 months), although the median age of onset of PLEVA (median: 60 months) was significantly younger than that of PLC (median: 72 months) (P = .03). The age distribution showed peaks at 2 to 3 years (24.8%) and 5 to 7 years (32%). A history of infection or drug intake preceded the skin manifestations in 30% and 11.2% of patients with PLC and PLEVA, respectively. The disease began most commonly during winter (35%) or fall (30%). The median duration was 20 months (range: 3-132 months) in patients with PLC and 18 months (range: 4-108 months) in patients with PLEVA. Involvement was diffuse in 74.2% of the patients, peripheral in 20.2%, and central in the remainder. The disease was recurrent in 77% of the patients (n = 80). Of the patients, 59% had pruritus, whereas 32% reported no symptoms; the remainder had fever, arthralgia, or both. Erythromycin estolate or ethylsuccinate was administered to 79.7% of the affected children; 66.6% of these showed at least a partial response.

LIMITATIONS

The analyzed data were collected retrospectively and biopsies were not performed in all patients.

CONCLUSIONS

PL is not an uncommon disease in childhood, with age peaks in the preschool and early school-age years. It is usually recurrent, and shows a seasonal variation with onset most often in the fall or winter. In childhood PL, erythromycin is an effective initial treatment choice.

Pityriasis lichenoides: pathophysiology, classification, and treatment

Pityriasis lichenoides (PL) is an uncommon, acquired spectrum of skin conditions that poses various challenges to patients as well as clinicians. It is a difficult and debatable disorder to diagnose, categorize, and treat. Besides these inherent obstacles, PL merits awareness because of its potential to progress to cutaneous lymphoma or an ulceronecrotic presentation, both of which carry a significant risk of mortality. The scope of PL presentations is delineated along a continuum of multiple variants including pityriasis lichenoides et varioliformis acuta (PLEVA), pityriasis lichenoides chronica (PLC), and febrile ulceronecrotic Mucha-Habermann disease (FUMHD). Classification of these presentations as separate subsets is debatable in view of their overlapping clinical, histopathologic, and etiologic features. PLEVA generally presents as an acute-to-subacute skin eruption of multiple, small, red papules that develops into polymorphic lesions and vacillates with periods of varying remissions as well as possible sequelae of hyper/hypopigmentation and varicella-like scars. PLC has a more gradual manifestation of very small red-to-brown flat maculopapules with mica-like scale; it also follows a relapsing course but with long periods of remission. FUMHD is an acute and severe generalized eruption of purpuric and ulceronecrotic plaques with associated systemic involvement and a mortality rate of up to 25%; hence, it should be approached as a dermatologic emergency.Histopathological evaluation of PL usually reveals dermal, wedge-shaped, lymphocytic infiltrate, epidermal spongiosis, parakeratosis, and variable necrosis of keratinocytes. PLC demonstrates more subtle histology whereas, at the other end of the spectrum, febrile ulceronecrotic FUMHD exhibits the most exaggerated histological features. The pathogenic mechanism behind PL is unclear although infectious or drug-related hypersensitivity reactions versus premycotic lymphoproliferative disorder are the mainstay theories. The foremost therapies for PLEVA and PLC are phototherapy, systemic antibacterials, and topical corticosteroids. Aggressive treatment with immunosuppressant and/or immunomodulating agents as well as intensive supportive care are recommended for FUMHD. We first describe a representative case of a 14-year-old boy with PLC who was successfully treated with narrow-band UVB. We then review the pathophysiology, classification, and treatment of PL.

Pityriasis lichenoides chronica: an association with autoimmune hepatitis?

Pityriasis lichenoides is an uncommon, benign skin disorder with two major variants: acute and chronic. Autoimmune hepatitis comprises heterogeneous forms of chronic hepatitis that are generally progressive and often fluctuating. Two major forms of this entity are recognized. Herein, we report the concurrence of pityriasis lichenoides chronica with type I autoimmune hepatitis in a child, which, to the best of our knowledge, has not been previously reported. Although it is hard to say whether an etiologic relationship or coincidental coexistence occurred between the two entities in our patient, some common mechanisms may be involved in both diseases.

Pityriasis lichenoides and its subtypes

Pityriasis lichenoides represents a unique group of inflammatory skin disorders that include pityriasis lichenoides et varioliformis acuta (PLEVA), febrile ulceronecrotic Mucha-Habermann disease (a subtype of PLEVA), and pityriasis lichenoides chronica. The history, epidemiology, clinical features, pathophysiology, and treatment of this group of conditions are reviewed in this manuscript.

Presence of chimeric maternally derived keratinocytes in cutaneous inflammatory diseases of children: the example of pityriasis lichenoides

During pregnancy, maternal cells may enter the fetal circulation and persist until adulthood. The fate of these cells remains unknown. As unexplained T-cell-mediated conditions such as pityriasis lichenoides (PL) may occur in children, we aimed at identifying maternal cells in lesional skin of PL and controls. Archived skin biopsy specimens from young males with PL, atopic dermatitis, or normal skin were scanned for the presence of female (presumably maternal) cells using fluorescence in situ hybridization (FISH) with X and Y chromosome-specific probes. Phenotyping of maternal cells relied on FISH combined with anti-CD45, anti-CD1a, or anti-cytokeratin labelling, identifying leukocytes, Langerhans cells, and keratinocytes, respectively. Maternal cells were found in PL (11/12) and controls (4/7), but their average frequency was higher in PL: 99 per million cells as compared to 5 per million cells in controls (P = 0.005). In the epidermis, the maternal microchimeric cells were labelled by anti-cytokeratin in all cases. We identified maternally derived keratinocytes in the skin of male children with inflammatory skin disorders. These cells may either help repair the damaged skin or home initially in the skin and trigger a host (child) versus graft (mother) disease.

CD30+ lymphoproliferative disorders: histopathology, differential diagnosis, new variants, and simulators

CD30+ lymphoproliferative disorders of the skin (CD30+ LPD) represent a well-defined spectrum of primary cutaneous T-cell lymphomas which have been recognized as distinct entities in recent lymphoma classifications. Lymphomatoid papulosis and anaplastic large-cell lymphoma share the expression of CD30 antigen as a common phenotypic hallmark but differ in regard to their clinical and histologic features as well as their biologic behavior. This article summarizes the histologic features of CD30+ LPD and presents recently identified new clinicopathologic variants of CD30+ LPD. There is an increasing number of reactive inflammatory disorders and neoplastic diseases which are composed of or contain a significant number of CD30+ cells and mimic LyP or anaplastic large cell lymphoma clinically or histologically. Differential diagnostic considerations focus on other lymphoproliferative processes with CD30+ tumor cells as well as non-lymphoid neoplasms and inflammatory simulators. The term CD30+ pseudolymphoma is proposed to designate inflammatory processes with CD30+ T cells. The final diagnosis of CD30+ LPD is based on a synthesis of clinical, histologic, phenotypic, and molecular genetic findings.

The role of cytotoxic skin-homing CD8+ lymphocytes in cutaneous cytotoxic T-cell lymphoma and pityriasis lichenoides

BACKGROUND

Pityriasis lichenoides (PL) is a rare cutaneous lymphoproliferative disorder of unknown origin. Malignant transitions of PL have been described, but are very rare. We recently observed the fatal course of a 26-year-old patient who presented with a clinical picture resembling PL but had cytotoxic CD8+ T-cell lymphoma of the skin (CxCTL). This case prompted us to reinvestigate the role of cytotoxic T lymphocytes in PL and its relationship to antiviral immunity.

METHODS

Skin biopsy specimens of 11 patients with PL and two biopsy specimens of CxCTL were included. In all, 5 biopsy specimens taken from healthy skin and 5 samples of varicella-zoster virus (VZV) skin lesions were analyzed for control purposes. The inflammatory infiltrate was characterized by immunohistochemistry using monoclonal antibodies against CD3, CD4, CD8, CD20, cutaneous lymphocyte-associated antigen (CLA), CCR4, CXCR3, Granzyme B, Tia-1, and MxA. Flow cytometry was used to analyze the expression of chemokine receptors on peripheral blood mononuclear cells in CxCTL.

RESULTS

The CxCTL skin lesions were dominated by a dense infiltration of CD8+ cytotoxic lymphocytes with a skin-homing CLA+ CCR4+ phenotype. PL and VZV skin lesions were also characterized by a predominantly CD8+ T cellular infiltrate with strong expression of the cytotoxic molecules Granzyme B and Tia-1 and the skin-homing molecules CLA and CCR4. Coexpression analyses confirmed that skin CLA+ CD8+ cytotoxic T cells are present in CxCTL, VZV, and PL skin lesions. Strong lesional production of the antiviral protein MxA, which is specifically induced by type I interferons, could be found in all investigated disorders. The study was based on histologic, immunohistologic, and flow cytometric analyses in a limited number of patients, because of the rareness of the investigated diseases.

CONCLUSION

Our results revealed a striking similarity between the immunohistologic picture of malignant CxCTL, benign PL, and VZV skin lesions. Strong expression of the antiviral protein MxA in all disorders supports the view that a common antiviral immune response pattern leads to aberrant skin recruitment of CLA+ CCR4+ cytotoxic T lymphocytes in PL and CxCTL.