Horizontal and vertical sections of scalp biopsy specimens from dermatomyositis patients with scalp involvement

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.

Comparative histopathological analyses of non-scarring alopecia in systemic lupus erythematosus patients in Lagos Nigeria

Background

Systemic lupus erythematosus (SLE) is known to cause non-scarring alopecia. However, histopathological evaluation is uncommon.

Aim

The objective of this study was to document the histopathology of non-scarring alopecia and to compare histopathology of alopecic and normal appearing scalp areas in SLE hair loss patients.

Patients and Methods

A cross-sectional comparative evaluation of scalp biopsies from 23 SLE patients; 12 with hair loss and 11 without was conducted over a 7-month period in 2020. A total of 58 scalp biopsies stained with H and E (23 vertical and 35 cross-sectional) were evaluated. Mucin deposit evaluation was done using Alcian blue (pH 2.5).

Results

There were no significant differences in the sociodemographic data between the patients. The SLE hair loss patients demonstrated mucin deposition (91.7%), reduced size/number of sebaceous glands (58.3%), epidermal atrophy (50.0%), naked arrector pili muscles (50.0%), lymphocytic infiltration (33.3%), pigment incontinence (16.7%), fibrous stellae (16.7%), increased telogen percentage, and increased terminal versus vellus hair ratios. On comparing the histopathology of those who had hair loss to those without hair loss, the only significant difference was in the number and size of sebaceous gland. There were no significant differences between scalp areas with and without hair loss in the SLE hair loss patients.

Conclusion

There are differences in size and number of sebaceous glands on histopathology between SLE patients who have hair loss and those who do not. Also, there are no histopathological differences between alopecic and non-alopecic scalp areas of SLE patient.

Histopathological risk factors for malignancy in dermatomyositis

AIMS

To identify possible histopathological risk factors for malignancy in skin biopsies of dermatomyositis patients.

METHODS AND RESULTS

We analysed clinical metadata and studied 30 skin biopsies of 11 patients with and 12 patients without associated malignancy that were treated in one secondary and one tertiary German medical center between 2009 and 2022 and fulfilling the EULAR/ACR classification criteria for dermatomyositis. Specimens were categorized by malignancy status and evaluated based on H&E, PAS, Alcian Blue and anti-CD123 immunohistochemistry stains. After correcting for multiple testing, biopsies of patients with cancer exhibited more severe basement membrane thickening (p<0.05) and pigment incontinence (p<0.05) compared to patients without tumour burden. Patients with numerous subepidermal melanophages had a more than 5-times increased odds ratio to suffer from an internal malignancy (OR 5.3, 95%CI 1.3-54.2, p<0.05). Furthermore, specimens of the malignancy group presented a distinct superficial distribution pattern of CD123+ plasmacytoid dendritic cells (PDCs, p<0.01). Extravascular eosinophils were absent in all cases.

CONCLUSIONS

Severity of basement membrane thickening, extent of pigment incontinence and superficial distribution pattern of CD123+ PDCs could serve as useful histopathological indicators of risk for malignancy in dermatomyositis.

Update on Cutaneous Signs to Assist in the Diagnosis of Dermatomyositis

PURPOSE OF REVIEW

Dermatomyositis (DM) is a heterogeneous idiopathic inflammatory myopathy that can be challenging to diagnose. Learning about the cutaneous manifestations in DM can assist with prompt diagnosis as well as subgroup classification. This review highlights recent data regarding cutaneous signs in DM and their associations with myositis-specific antibodies (MSAs).

RECENT FINDINGS

Several novel DM skin signs have recently been reported. Novel and confirmatory data have helped to define more clearly the associations between various cutaneous manifestations and MSAs. Awareness of the diverse cutaneous phenotypes can help with the timely diagnosis of DM. As some MSAs are associated with atypical skin features and/or characteristic patterns of clinical findings, knowledge of these associations can help clinicians to recognize DM patients. Understanding how the prevalence and presentation of various cutaneous signs differ among ethnically diverse patients is a high priority for further study.

Do histopathological features correlate with systemic manifestations in dermatomyositis? Analysis of 42 skin biopsy specimens from 22 patients

BACKGROUND

Understanding whether specific histopathologic features on skin biopsy are predictive of systemic associations in dermatomyositis would be useful to guide clinical screening.

METHODS

Via retrospective medical record search, clinical and laboratory findings of patients with dermatomyositis were documented. Existing skin biopsy slides were re-reviewed blindly.

RESULTS

Of all biopsy specimens (n=42), the most frequent histopathological finding was vacuolar interface dermatitis (95%). Other features included perivascular lymphocytic infiltrate (71%), increased dermal mucin (40%), vessel wall thickening (12%), follicular plugging (9.5%) and dermal sclerosis (7%). Neutrophilic infiltrate was observed in 3 biopsies from a patient with adualimumab-associated DM. Vasculitis was not observed. There was no statistically significant difference in the presence of any histopathological feature and that of various systemic manifestations [i.e. myopathy, interstitial lung disease (ILD) and malignancy]. However, we observed that dense lichenoid infiltrate rather than pauci-inflammatory changes correlated with severe itching (p < 0.001) Patients with MDA-5 antibodies were significantly more likely to have vasculopathy than those without (p=0.029*).

CONCLUSIONS

No dermatopathological feature was reliably predictive of myopathy, ILD or malignancy. This finding implies that regardless of histopathologic findings, patients should be screened for associated conditions, as clinically indicated.

Increased MxA protein expression and dendritic cells in spongiotic dermatitis differentiates dermatomyositis from eczema in a single-center case-control study

BACKGROUND

Dermatomyositis (DM) is conventionally characterized by interface dermatitis (ID) on skin histopathology. A subset of DM patients has skin biopsies showing spongiotic dermatitis (SD), a histopathology more commonly seen in eczema. In this study, we aimed to (a) identify the percentage of clinically diagnosed DM patients with SD skin biopsies, (b) identify cytokine and cell markers that can help determine if a SD skin biopsy is consistent with DM.

METHODS

In this case-control study, biopsy specimens from ten DM patients with SD (DM-SD) were compared to specimens from ten healthy controls, ten patients with eczema, and 12 patients with DM with ID (DM-ID). Specimens were stained by immunohistochemistry for MxA, IFN-β, CD11c, and BDCA2. One-way ANOVA with Bonferroni's multiple comparison test was used to compare protein expression between groups.

RESULTS

Eleven of 164 (6.7%) patients with a clinical diagnosis of DM at our tertiary care center were identified as having SD. MxA, IFN-β, CD11c, and BDCA2 protein expression was significantly higher in DM-SD compared to eczema and healthy controls. Expressions of MxA, IFN-β, and BDCA2 were not significantly different between DM-SD and DM-ID.

CONCLUSION

Increased MxA, IFN-β, CD11c, and BDCA2 protein expression may aid in distinguishing between DM-SD and eczema and warrants further investigation.

Quantitative Assessment of Eosinophils in Dermatomyositis Skin Biopsies With Correlation of Eosinophils to Pruritus and Other Clinical Features

ABSTRACT

The objective of this retrospective study was to analyze dermatomyositis skin biopsies for the presence of eosinophils and correlate this finding with other histopathologic and clinical characteristics. Cases of dermatomyositis evaluated in a single dermatologist's adult autoimmunity practice over a 2.5-year period were identified via ICD-10 diagnosis code. Dermatopathology archives were then searched for any corresponding biopsies consistent with dermatomyositis, and those identified were assessed for eosinophils, adnexal involvement, epidermal atrophy, dermal mucin, and basement membrane thickening. Histopathologic findings were correlated with key clinical features, including itch. A total of 39 biopsies from 17 patients were included. Eosinophils were noted in 44% of biopsies (n = 17) from 12 patients. Dermal mucin deposition and adnexal interface dermatitis were noted in 72% (n = 28) and 44% (n = 17) of biopsy specimens, respectively. Of 12 patients with eosinophils present in at least 1 biopsy specimen, 11 (92%) patients had a clinical history of pruritus of their skin lesions (P = 0.052). Limitations of this study include retrospective design and small number of patients.

IL18-containing 5-gene signature distinguishes histologically identical dermatomyositis and lupus erythematosus skin lesions

Skin lesions in dermatomyositis (DM) are common, are frequently refractory, and have prognostic significance. Histologically, DM lesions appear similar to cutaneous lupus erythematosus (CLE) lesions and frequently cannot be differentiated. We thus compared the transcriptional profile of DM biopsies with CLE lesions to identify unique features. Type I IFN signaling, including IFN-κ upregulation, was a common pathway in both DM and CLE; however, CLE also exhibited other inflammatory pathways. Notably, DM lesions could be distinguished from CLE by a 5-gene biomarker panel that included IL18 upregulation. Using single-cell RNA-sequencing, we further identified keratinocytes as the main source of increased IL-18 in DM skin. This study identifies a potentially novel molecular signature, with significant clinical implications for differentiating DM from CLE lesions, and highlights the potential role for IL-18 in the pathophysiology of DM skin disease.

IL-18 distinguishes dermatomyositis skin inflammation from cutaneous lupus erythematosus lesions.

Alopecia as a systemic disease

Alopecia is a skin condition of great social and psychologic impact. Primary alopecia originates from the hair follicles and usually does not have systemic manifestations; however, secondary alopecia can affect the hair follicles in the setting of systemic diseases, medications, and external trauma. Connective tissue diseases, granulomatous diseases, bullous diseases, infections, and tumors are some of the systemic diseases that will be covered in this review. Trichoscopy is a useful noninvasive tool that can help with the diagnosis in the office and can guide the selection of the optimal site for the scalp biopsy. Histopathology is the ultimate tool for the diagnosis in most cases of secondary alopecia and can be performed on vertical and horizontal sections. In most cases, treating the underlying condition is the single most important strategy, but topical treatments for the alopecia are also applied.

[What's new in internal medicine?]

What's new in internal medicine will be dedicated to three topics: i) inflammatory myopathies constituting a heterogenous group of diseases whose clinical manifestations, immunological abnormalities, treatment response and outcomes vary widely; ii) alterations of gut microbiota contributing to the occurrence or development of a range of conditions, including autoimmune diseases for which further work is necessary to understand the correlation of dysbiosis with these diseases; iii) the reciprocal relationship between obesity, metabolic syndrome, atherosclerosis and autoimmune diseases. New data concerning systemic sclerosis, cutaneous vasculitis, adult Still's disease, autoantibodies anti DFS70, Epstein Barr virus and autoimmune diseases were also highlighted.