Follicular Acantholysis: A Subtle Clue to the Early Diagnosis of Pemphigus Vulgaris

Histopathology of autoimmune bullous dermatoses: What's new?

Autoimmune bullous dermatoses are characterized by the presence of tissue-bound and often circulating pathogenic autoantibodies targeting structural components of the skin and/or mucous membranes. The diagnostic workup for this heterogeneous group of disorders consists of a multi-step process, of which the light microscopic examination is a crucial component. This review is organized following a classification scheme that is based on two main histopathologic features, namely level of intraepithelial split and composition of the inflammatory infiltrate. Overall, we aim to place emphasis on the histopathologic clues that can assist pathologists in differential diagnosis and review the updates in the literature.

Extrusion of pilosebaceous units into blisters of patients affected by a new variant of endemic pemphigus in El Bagre, Colombia, South America

BACKGROUND

A new variant of endemic pemphigus foliaceus is present in El Bagre, Colombia and surrounding municipalities (El Bagre-EPF) that affects the skin, and in some presentations affects other organs with autoantibodies directed against cell junctions.

METHODS

We studied 200 El Bagre-EPF patient perilesional skin biopsies, as well as 200 skin biopsies from normal controls in the endemic area.

RESULTS

We observed blister extrusions of sebaceous glands or entire pilosebaceous units via the isthmus in 23% of the patients and not in the controls.

CONCLUSIONS

The extrusion of hair follicular unit contents is consistent with our previous pathologic findings of autoreactivity to these units, and their observed clinical decrease in patients affected by El Bagre-EPF. This article is protected by copyright. All rights reserved.

Extension of separation along the follicular epithelium and follicular basement membrane in pemphigus and bullous pemphigoid

BACKGROUND

The outer root sheath of hair follicle and the interfollicular epidermis are continuous and basically similar in many aspects. The expression of various basement membrane (BM) components in the upper portion of the hair follicle is similar to that of the interfollicular BM. The extension of acantholysis into the adnexal structures was highlighted in the pemphigus group of diseases. On the other hand, extension of separation down the hair follicle BM has not been studied in subepidermal autoimmune bullous dermatoses. The aim of the present work was to study the extension of separation along follicular epithelium and follicular BM in pemphigus and bullous pemphigoid.

METHODS

This retrospective study was conducted on pemphigus and bullous pemphigoid cases. For each case, 4-μm-thick sections stained with hematoxylin and eosin were examined for the presence of hair follicles and the extension of separation down follicular epithelium and follicular BM.

RESULTS

Positive extension of acantholysis down the follicular epithelium was seen in 23/27 (85.2%) of pemphigus vulgaris (PV) and 7/9 (77.8%) of pemphigus foliaceus (PF) cases with hair follicles. Follicular extension was limited to the infundibulum in PF but down the entire follicular length in PV. As for bullous pemphigoid (BP) cases, 20/26 cases (76.9%) that had hair follicles showed positive extension of the separation down the follicular BM. The cellular infiltrate detected was identical in its nature and density to that of subepidermal blister in all cases.

CONCLUSIONS

Extension of the separation along follicular epithelium and follicular basement membrane was observed in PV, PF, and BP without significant difference.

Histopathology of Pemphigus Vulgaris Revisited

ABSTRACT

Pemphigus vulgaris (PV) is a severe, potentially life-threatening autoimmune blistering disease, which is common in India. Although there is abundant literature on clinical and immunologic features, comprehensive studies on its histopathology are lacking. The aim of this study was to describe the histopathologic and immunofluorescence features as well as discuss various diagnostic pitfalls of PV. Histopathologic and immunofluorescence (DIF/IIF) findings were reviewed for 169 biopsies from 2007 to 2017 (11 years). The 169 samples included 152 skin, 16 oral mucosal, and 1 corneal biopsy. Maximum prevalence was noted in the fifth decade (57%) with a slight male preponderance. Vesicles were seen in 149 cases (88%), the level of which was suprabasal in 91(61%) and both suprabasal and intraepidermal in 50 cases (33.5%). Acantholytic cells were present in 142 cases (95%). Acantholytic keratinocytes showed rounded and polygonal acantholysis. 86 (51%) cases showed evidence of regeneration. Adnexal involvement was seen in 92 cases, commonest in the hair follicles. Unusual histologic findings included: intraepidermal bulla, absence of dermal inflammation, free floating hair shafts, multinucleated epithelial cells, eosinophil predominance; all of which are discussed. DIF was performed in 166 cases, of which 163 were positive (98%), and IgG was the commonest immunoreactant (96%). IIF was performed in 11 cases, of which 9 cases were positive for Dsg3. Although the diagnosis of PV rests on combined clinical, histologic, and IF features, histopathology as the sole means is also a powerful tool. It is important to be aware of the diagnostic pitfalls to optimize its utility.

Incidental Acantholysis in Hailey-Hailey Disease (Microscopic Nikolsky Sign): An Underappreciated Histologic Sign

Identification of subtle disease-specific histologic changes may be of significant help in early diagnosis of acantholytic skin diseases. Hailey-Hailey disease (HHD) is an autosomal dominant genodermatosis characterized by vesiculoerosive lesions favoring the intertriginous areas. Histologically, HHD is characterized by full-thickness acantholysis of the spinous layer in association with dyskeratosis of individual keratinocytes; a pemphigus vulgaris-like suprabasal pattern of acantholysis may be observed in the earliest stages of disease. HHD is characterized by highly variable expressivity regarding the age at onset and severity of the disease. Patients may present with late-onset and/or only mild disease. We report the recurrent presence of incidental foci of variably extensive, subclinical acantholysis in multiple bioptic specimens taken from a patient with known HHD for dermatologic conditions other than HHD. Such histologic finding has gone underappreciated in the literature, despite being a likely frequent occurrence in skin biopsies from HHD patients; recognition of this finding might represent a valuable diagnostic clue in selected cases of HHD.

The Significance of Scalp Involvement in Pemphigus: A Literature Review

Scalp is a unique location for pemphigus because of the abundance of desmogleins localized in hair follicles. Scalp involvement is observed in up to 60% of patients in the course of pemphigus. The lesions may occasionally lead to alopecia. Unforced removal of anagen hairs in a pull test is a sign of high disease activity. Direct immunofluorescence of plucked hair bulbs is considered a reliable diagnostic method in patients with pemphigus. Follicular acantholysis is a characteristic histopathological feature of pemphigus lesions localized on the scalp. Trichoscopy may serve as a supplementary method in the diagnosis of pemphigus. This review summarizes the most recent data concerning scalp involvement in pemphigus vulgaris and pemphigus foliaceus. A systematic literature search was conducted in three medical databases: PubMed, Embase, and Web of Science. The analysis included literature data about desmoglein distribution in hair follicles, as well as information about clinical manifestations, histopathology, immunopathology, and trichoscopy of scalp lesions in pemphigus and their response to treatment.

Direct immunofluorescence on hair follicles--present and future perspectives

Direct immunofluorescence (DIF) is an important tool for evaluating bullous autoimmune and connective tissue disorders. We report 21 cases of pemphigus vulgaris, bullous pemphigoid and lupus erythematosus that were investigated by performing DIF on scalp hair follicles. The study was done using a simplified technique of preparing the hairs for DIF testing. The anagen hairs tested positive in pemphigus vulgaris patients while the telogen hairs were negative. In bullous pemphigoid and lupus erythematosus cases hair DIF presented negative results.Hair DIF has the potential of taking the place of skin or mucosal DIF in pemphigus patients if performed on anagen hair follicles. The technique used to perform hair DIF is important in obtaining reliable results and eliminating the possibility of generating false-negative testing. Larger studies are needed in order to validate this method.

Immunofluorescence of the outer root sheath: an aid to diagnosis in pemphigus

BACKGROUND

The direct immunofluorescence (DIF) pattern of the outer root sheath (ORS) of the hair follicle in patients with pemphigus resembles that of perilesional skin. We performed DIF on anagen and telogen hair ORS from patients with pemphigus and compared the findings with those of perilesional skin.

AIM

To assess the sensitivity of DIF in the ORS of anagen and telogen hair in patients with pemphigus with positive DIF results in perilesional skin.

METHODS

In total, 50 patients with active pemphigus and positive DIF findings in perilesional skin were selected for the study. Anagen hair was obtained from the scalp by the same method used for a trichogram, and telogen hair was selected by combing the hair and collecting the loose strands of hair from the comb. The hair type was further confirmed by microscopy. Hair samples were transported in Michel medium and prepared for DIF by mounting on a slide without sectioning. Anagen and telogen hair samples were also collected from 50 controls.

RESULTS

Immunological deposits characteristic of pemphigus were found in the ORS of anagen and telogen hairs in all 50 patients, but in none of the 50 controls. Positive DIF findings were seen in scalp hair irrespective of the presence of scalp lesions. Of the 50 patients with pemphigus, 46 were diagnosed with pemphigus vulgaris, 2 with pemphigus vegetans, and 1 each with pemphigus foliaceus and pemphigus erythematosus, based on the clinical, histopathological and DIF findings. All the pemphigus variants had positive DIF findings in the ORS.

CONCLUSIONS

Using DIF on telogen hair ORS promises to be a useful tool for diagnosis and follow-up in cases of pemphigus.

Demonstration of pemphigus-specific immunofluorescence pattern by direct immunofluorescence of plucked hair

BACKGROUND

Direct immunofluorescence (DIF) of perilesional skin is the gold standard in the diagnosis of pemphigus. Since the outer root sheath (ORS) of anagen hair is structurally analogous to epidermal keratinocytes, pemphigus specific immunofluorescence pattern may be present in the ORS.

METHODS

Twenty consecutive patients of pemphigus were enrolled in the study, irrespective of any other inclusion or exclusion criteria. Hairs were plucked in a similar fashion to that of trichogram. Approximately 5 anagen hairs were selected processed and stained with fluorescein isothiocyanate (FITC) conjugates. DIF of perilesional skin and indirect immunofluorescence (IIF) were carried out simultaneously. DIF of hair was also done in equal numbers of controls with other dermatoses.

RESULTS

Intercellular deposition of IgG was seen in the ORS of anagen hair in 85% of patients (n = 17). The test was positive in all patients who had scalp lesions (n = 10); however, it was also positive in 7 patients (77.7%) who did not have scalp lesions. The test was negative in 3 patients; two of whom were elderly and had sparse scalp hair. The other patient only had mucosal lesion. The test was negative in the control group.

CONCLUSION

DIF of hair is a simple, non-invasive test. In future, it may alleviate the need for skin biopsies, in patients with pemphigus.

Immunofluoresence of the outer root sheath in anagen and telogen hair: an aid to diagnosis in pemphigus

Desmoglein 1 and 3 are distributed in the outer root sheath (ORS) of the hair follicle. Direct immunofluoresence (DIF) pattern of ORS in cases of pemphigus resembles the DIF pattern of the perilesional skin. We performed a DIF of the anagen and telogen hair ORS in a case of pemphigus and correlated it with the DIF findings of perilesional skin. Telogen hair ORS promises to be a useful tool in performing DIF for the purpose of diagnosis and follow-up in cases of pemphigus

A study on plucked hair as a substrate for direct immunofluorescence in pemphigus vulgaris

BACKGROUND

It has recently been demonstrated in a study on 15 patients that plucked hair can be used as a substrate for direct immunofluorescence (DIF) in pemphigus.

OBJECTIVE

Our aim was to assess the sensitivity of DIF on plucked hairs in pemphigus vulgaris (PV) patients with positive DIF of oral mucosa.

METHODS

One hundred and ten new PV patients were enrolled in the study. They all showed the typical clinical and histological findings as well as positive DIF of the oral mucosa, diagnostic for PV. Approximately 30 hairs were obtained in the same way as for the trichogram. The hairs with their outer root sheaths (ORS) were processed for DIF in order to detect immunoglobulin G and C3.

RESULTS

Immunodeposits favouring PV were demonstrated in the ORS of 100 cases showing a sensitivity of 91%.

CONCLUSION

Regarding the relatively high sensitivity of DIF on plucked hair in PV patients with positive oral mucosal DIF in our study, it seems that hair plucking is a suitable alternative to the more invasive techniques of skin or mucosal biopsy for obtaining specimens for DIF in PV.