The significance of eosinophils in hypertrophic lichen planus

Hypertrophic Lichen Planus: An Up-to-Date Review and Differential Diagnosis

CONTEXT.—

Hypertrophic lichen planus (HLP) is a variant of lichen planus that can be difficult to diagnose based on histopathologic features alone. Thus, patient clinical history and clinicopathologic correlation are essential considerations to make the correct diagnosis.

OBJECTIVE.—

To discuss the clinical and histologic presentation of HLP and provide a thorough review of commonly encountered mimickers in the differential diagnosis.

DATA SOURCES.—

Data were derived from a literature review, personal clinical and research experiences, and a review of cases in the archives of a tertiary care referral center.

CONCLUSIONS.—

In general, HLP involves the lower extremities and is characterized by thickened, scaly nodules and plaques that are often pruritic and chronic in nature. HLP affects both males and females and is most common in adults 50 to 75 years of age. Unlike conventional lichen planus, HLP tends to have eosinophils and classically displays a lymphocytic infiltrate most concentrated around the tips of rete ridges. The differential diagnosis for HLP is broad and encompasses numerous entities in many different categories, including premalignant and malignant neoplasms, reactive squamoproliferative tumors, benign epidermal neoplasms, connective tissue disease, autoimmune bullous disease, infection, and drug-related reactions. Therefore, a high index of suspicion must be maintained to avoid a misdiagnosis and potential inappropriate treatments.

Dermatomyositis with Eosinophils

Dermatomyositis is an idiopathic inflammatory myopathy that often presents with symmetric proximal skeletal muscle weakness and characteristic skin findings. Typical skin biopsy findings include vacuolar changes of the basal layer, increased dermal mucin, and a predominantly lymphocytic infiltrate. We report a case of dermatomyositis presenting as intensely pruritic papules and plaques, with initial histopathology being atypical of dermatomyositis due to the presence of eosinophils. The initial biopsy demonstrated a superficial dermatitis with eosinophils, initially thought to represent a drug eruption. A second biopsy of the same cutaneous manifestation was performed at a later time given high clinical suspicion for dermatomyositis and demonstrated a more classic vacuolar interface dermatitis with increased mucin and an absence of eosinophils. Notably, increased pruritus was specifically associated with the lesion that demonstrated tissue eosinophilia. The case illustrates the importance of considering tissue eosinophilia in the histologic presentation of dermatomyositis.

The role of eosinophils in the differential diagnosis of inflammatory skin diseases

Eosinophils are known to be present in inflammatory skin diseases, but their diagnostic utility is not well established. Upon review of the published status of lesional eosinophils, several categories were identified. 1) Lesional eosinophils highly characteristic such that, in their absence, the pathologist may question the diagnosis. These include arthropod bite reactions and scabies, urticarial dermatitis, and other eosinophilic dermatoses. 2) Lesional eosinophils rare or absent, such that, in their presence, the pathologist may question the diagnosis. These include pityriasis lichenoides, graft versus host disease, and connective tissue disorders. 3) Lesional eosinophils variable and, while in some cases expected, are not required for diagnosis. These include drug reactions, atopic dermatitis and allergic contact dermatitis. 4) Lesional eosinophils variable and not expected but may be seen to a limited extent. These include lichen planus and psoriasis.

Adult Blaschkitis With Lichenoid Features and Blood Eosinophilia

There have been many reports of congenital and acquired dermatoses that trail Blaschko lines. Lichen striatus is representative of an acquired cutaneous linear inflammatory dermatosis running along the lines of Blaschko, characterized histopathologically by the predominance of lichenoid infiltration. Adult blaschkitis, however, is considered under the same disease spectrum as lichen striatus and is characterized by a spongiotic reaction pattern. Few differences have been recognized between lichen striatus and adult blaschkitis such as age of onset, triggers, distribution, histopathology, and response to treatment.

A case of male patient with adult blaschkitis presenting as unilateral asymptomatic erythematous edematous papules, papulovesicles, and plaques over Blaschko’s lines, in which skin biopsy revealed coexistent pathological features of lichen striatus and adult blaschkitis along with blood eosinophilia, has been presented here. This may add to the cumulative evidence on the pathogenesis of adult blaschkitis as an allergic reaction to an unknown inciting allergen.

Evidence to consider adult blaschkitis as part of the lichen striatus spectrum is growing. Triggers for such skin reactions remain diverse. This case presentation suggests that adult blaschkitis could be triggered by an allergic response evidenced by the blood eosinophilia when other causes of eosinophilia are excluded.

Lichen planus - a clinical guide

Lichen planus (LP) is a chronic lichenoid inflammatory disorder of the skin, mucosa and of the appendages. LP is classically characterized by the presence of a rich infiltration of inflammatory T cells, which migrate in the upper part of the dermis, arranged in a band-like pattern. Different sub types of the disease have been so far described. Albeit LP is clinically well defined, the disease still represents a therapeutic enigma. Especially with regard to mucosal or scalp affecting LP types, which often present a recalcitrant and treatment unresponsive course, efficacious therapeutic options are still lacking. Thus, LP represents a disease with a high psychosocial burden. Yet, development in the deciphering of LP pathogenesis reveals possible new druggable targets, thus paving the way for future therapeutic options. In this clinical guide, we summarize the current clinical knowledge and therapeutic standards and discuss the future perspective for the management of LP.

Distinction Between Hypertrophic Lichen Planus and Squamous Cell Carcinoma Requires Clinicopathologic Correlation in Difficult Cases

ABSTRACT

Distinguishing hypertrophic lichen planus (HLP) and squamous cell carcinoma (SCC) can be diagnostically challenging because of overlapping clinical and histopathological features. This study characterizes histopathological features in HLP and SCC, assessing their utility in diagnosing atypical squamous proliferations. We compared 12 histopathological features of 15 HLP and 11 SCC biopsies from the lower extremities. We then reviewed 16 cases that were diagnosed as atypical squamous proliferations with differential diagnoses of HLP versus SCC. Clinical follow-up allowed for retrospective categorization of these difficult cases as HLP or SCC. HLP showed significant differences in hyperorthokeratosis (P = 0.04), wedge-shaped hypergranulosis (P = 0.0033), and irregular psoriasiform hyperplasia (P = 0.004), whereas parakeratosis (P = 0.001), solar elastosis (P = 0.001), deep extension (P = 0.02), and perforating elastic fibers (P = 0.0001) were significant for SCC. A scoring system based on these significant differences was devised to aid the classification of difficult cases. 56% of the difficult cases received an "indeterminate" score. A score favoring HLP had a sensitivity of 44% and a specificity of 71%. Although significant differences were identified between cases of definitive HLP and SCC, these histopathological features were unable to distinguish difficult cases, highlighting the need for clinicopathological correlation in patients with atypical squamous proliferations of the lower extremities. Many difficult cases had histologic features that could not be evaluated because of the superficial nature of the biopsy. Therefore, obtaining a deep wedge or punch biopsy may facilitate a diagnosis in cases with a differential diagnosis of HLP and SCC.

Hypertrophic lichenoid dermatitis immune-related adverse event during combined immune checkpoint and exportin inhibitor therapy: A diagnostic pitfall for superficially invasive squamous cell carcinoma

Immune checkpoint inhibitors (ICIs) for cancer treatment have revolutionized the field of medicine. However, an unintended but frequent consequence of ICI therapy is the development of cutaneous immune-related adverse events (irAEs), such as lichenoid dermatitis irAEs (LD-irAEs). The hypertrophic variant of LD-irAE may be a diagnostic challenge since it can mimic superficially invasive squamous cell carcinoma (SCC). A 79-year-old woman with metastatic melanoma who began treatment with an ICI-pembrolizumab-plus exportin-1 (XPO1) inhibitor presented after 1 month of therapy with symmetrical violaceous papules coalescing into plaques and with two nodules of the bilateral dorsal hands. Biopsy of the nodules revealed an actinic keratosis and atypical epidermal proliferation concerning for SCC. However, in the ensuing 3 weeks, the patient developed multiple new erythematous, violaceous, and scaly macules and papules, some coalescing into plaques on the extremities. Biopsies of these lesions revealed exuberant irregular epidermal hyperplasia with hypermaturation and lichenoid infiltrate concentrated at the base of the elongated, broadened rete ridges, consistent with hypertrophic LD-irAE. Treatment included topical fluocinonide ointment, intralesional triamcinolone injections and oral acitretin. Distinguishing hypertrophic LD-irAE and SCC can be challenging since both entities share histopathologic features; thus, correlation with clinical presentation is essential for diagnosis and optimal patient management.

Lichenoid dermatoses involving the vulva: A clinical-pathologic correlation✰

The lichenoid tissue reaction pattern generally signifies cytotoxic damage to the epithelium. When such reaction pattern occurs on vulvar skin or mucosa, the effects can result in considerable morbidity. None of the entities discussed in this review are entirely unique to the vulva, however, some entities may classically occur at this site, while others tend to be widespread diseases that may incidentally affect vulvar skin and mucosa. Given the complex anatomy of the vulva and the bridging of a site showing both keratinizing squamous epithelium and non-keratinizing squamous mucosa, histopathologic features may display variation in presentation. Although identification of a "lichenoid reaction pattern" alone may provide insight into the disease process, understanding of clinical presentation and specific sites of involvement, along with recognition of the nuanced features of the disease entities can help establish a specific diagnosis. Accurate histopathologic diagnoses by pathologists can improve the ability for treating clinicians to implement timely and effective treatment.

Lichen Planopilaris in Women: A Retrospective Review of 232 Women Seen at Mayo Clinic From 1992 to 2016

OBJECTIVE

To characterize the clinicopathologic findings, comorbidities, and treatment outcomes of women with lichen planopilaris (LPP).

METHOD

In this retrospective review of women with LPP at Mayo Clinic from 1992 to 2016, we searched for scarring alopecia in all female patients aged 1 to 100 years from January 1, 1992, through December 31, 2016. Men were excluded from this study to more accurately determine the association of hormonal factors in LPP pathogenesis. Two hundred thirty-two patients were included as they met diagnostic criteria for LPP based on clinicopathologic correlation, with 217 having confirmatory biopsies.

RESULTS

We identified 232 women with LPP (mean age, 59.8 years). Of those, 92.7% (215) presented with hair loss; 23.7% (55) had preceding inflammation; 30.6% (71) had thyroid disease, including hypothyroidism (23.2%; 54); and 9.4% (22) had vitamin D deficiency. Incidence of depression and anxiety was 45.7% (106) and 41.8% (97), respectively. History of total abdominal hysterectomy/bilateral salpingo-oophorectomies and hormone replacement therapy was found in 16.8% (39) and 16.4% (38), respectively. Lichen planus at other body sites occurred in 16.4% (38) of patients; and 53.2% (123) had slowing of disease progression or disease stabilization, often requiring combination therapies. In those who achieved slowing or stabilization of disease, mean time to recurrence was 1.8 year. The mean time to remission was 1.1 year.

CONCLUSION

The typical LPP patient is a 60-year-old female with vertex scarring alopecia who presents with burning, erythema, inflammation, and scale. Almost half of patients will have comorbid autoimmunity. As previously reported, LPP is associated with thyroid disease. We also found higher rates of depression, anxiety, nutritional deficiencies, and skin cancer than reported in the general population.

Epidemiologic and Clinical Differences Between Classic and Hypertrophic Lichen Planus in Nigeria

Introduction. Lichen planus is a chronic inflammatory skin disease known to have several clinical variants with attended variable clinical outcomes. Certain complications have been observed in the hypertrophic type, which were not found in association with the classic variant.

Objective: To identify the epidemiologic and clinical differences between the classic and hypertrophic lichen planus and clinical correlates.

Material and Methods. Of 104 participants with lichen planus included in the study, 49 had classic and 55 hypertrophic lichen planus. Demographic and clinical information was obtained. Diagnosis of lichen planus was made clinically and confirmed with histology. The participants were screened for metabolic syndrome, hepatitis B, and C.

Results: Mean age of all patients was 37.20±13.39 years, with no age and gender differences between the participants with classic and hypertrophic lichen planus. Classic lichen planus was more likely to be painful, (8.2% vs 0.0, p=0.046), generalized (95.9% vs 16.4%, p<0.001), involve the oral mucosa (38.8% vs 0.0, p<0.001), the nails (38.8% vs 1.8, p<0.001), present with kobnerisation (55.1% vs 5.5%,<0.001), Wickhiam striae (69.4% vs 16.4%, p<0.001), associated with Hepatitis B vaccination (16.3% vs 3.6%, p<0.028) and anti HCV positivity (16.3% vs 0.0%, p=0.002). Hypertrophic lichen planus was significantly associated with impaired glucose tolerance/diabetes mellitus (16.4% vs 2.0%, p=0.013), dyslipidemia (74.5% vs 40.8%, p=0.001) and saw-tooth histologic appearance compared to classic type.

Conclusion: Hypertrophic lichen planus is more likely to be associated with metabolic complications compared to the classic type. Further studies are needed to loink this difference t chronic inflamation.

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.

Inflammatory Dermatopathology for General Surgical Pathologists

Owing to the wide variety and complexity of inflammatory skin diseases, inflammatory dermatopathology can be a challenging topic for dermatopathologists and general surgical pathologists alike. Following a basic tissue reaction pattern approach, this article reviews the most common and important entities of each pattern, with emphasis on differential diagnosis, diagnostic pitfalls, and appropriate workup when indicated. A few dermatologic emergencies are also discussed.

Update on lichen planus and its clinical variants

Lichen planus (LP) is an inflammatory skin condition with characteristic clinical and histopathological findings. Classic LP typically presents as pruritic, polygonal, violaceous flat-topped papules and plaques; many variants in morphology and location also exist, including oral, nail, linear, annular, atrophic, hypertrophic, inverse, eruptive, bullous, ulcerative, lichen planus pigmentosus, lichen planopilaris, vulvovaginal, actinic, lichen planus-lupus erythematosus overlap syndrome, and lichen planus pemphigoides. Clinical presentation of the rarer variant lesions may be largely dissimilar to classic LP and therefore difficult to diagnose based solely on clinical examination. However, histopathological examination of LP and LP-variant lesions reveal similar features, aiding in the proper diagnosis of the disease. Management of LP and LP variants aims to control symptoms and to decrease time from onset to resolution; it often involves topical corticosteroids, but varies depending on the severity and location of the lesion. The literature contains an array of reports on the variations in presentation and successful management of LP and its variants. A familiarity with LP and its variants is important in achieving timely recognition and management of the disease.

Eosinophils in biopsy specimens of lichen sclerosus: a not uncommon finding

BACKGROUND

Evolving lesions of lichen sclerosus (LS) pose a diagnostic challenge owing to an absence of classic findings of epidermal atrophy, dermal sclerosis, a band-like lymphocytic infiltrate and the presence of eosinophils.

METHODS

Retrospective specimens of LS were reviewed. Demographic information, biopsy vs. excision and the following histopathological characteristics were noted: presence and number of eosinophils, epidermal hyperplasia, spongiosis, early/transitional LS, well-developed LS and coexisting squamous cell carcinoma (SCC). Linear regression analysis was performed.

RESULTS

The data consisted of 66 biopsies (36 male [M], 30 female [F]), from 53 individuals (33M, 20F), including 57 genital and 9 extragenital biopsies. Seven biopsies showed SCC, 28 showed epidermal hyperplasia and 14 exhibited spongiosis. Thirty-five specimens were early/transitional LS and commonly exhibited epidermal hyperplasia (57%), epidermotropism of lymphocytes (97%) and basement membrane thickening (97%). Thirty-five biopsies (53%) contained eosinophils (23 early/transitional lesions). Male gender (p = 0.074) was associated with increased eosinophils. The presence of SCC (p = 0.014) was a significant predictors of eosinophil number.

CONCLUSIONS

Epidermal hyperplasia, epidermotropism of lymphocytes and basement membrane thickening are helpful features in identifying early LS. Eosinophils are not an uncommon finding in LS and are most common in male genital lesions and in LS associated with SCC.