Diagnostic Utility of Direct Immunofluorescence on Paraffin-Embedded Skin Biopsy Samples for the Diagnosis of Autoimmune Vesiculobullous Lesions

Background Autoimmune vesiculobullous diseases (AIBDs) are a group of diseases characterized by blisters of the skin/mucosa due to the presence of circulating autoantibodies against antigens in the epidermis or the dermo-epidermal junction. Direct immunofluorescence (DIF) for immunoglobulin (Ig)G, IgC3, and IgA on fresh-frozen tissue is the gold standard diagnostic test for AIBDs. However, DIF in the absence of frozen tissue is challenging for the diagnosis of AIBDs. This study aimed to analyze the practical utility of DIF using paraffin-embedded skin biopsy rather than fresh frozen tissue for the diagnosis of AIBDs. Methodology This cross-sectional comparative study included 30 cases of AIBDs. DIF for IgG and IgA was performed on paraffin-embedded tissue (PE-DIF) after proteinase digestion on histopathologically confirmed 15 pemphigus vulgaris (PV), three pemphigus foliaceous (PF), four bullous pemphigoid (BP), three dermatitis herpetiformis (DH), three subcorneal pustular dermatosis (SCPD), and one case each of linear IgA disease and pemphigoid gestationis (PG). PE-DIF staining pattern was compared with the DIF on fresh frozen tissue (FF-DIF). Results All cases of PV and PF showed an intercellular IgG chicken wire staining pattern similar to FF-DIF. However, background staining was more intense in PV cases while less intense in PF cases. Three BP cases showed linear IgG staining in PE-DIF. DH, SCPD, linear IgA disease, and PG cases did not show IgG positivity. Out of three DH cases, two cases showed granular IgA positivity while linear IgA positivity along the basement membrane was seen in a single case of linear IgA disease. Negative IgG staining was observed in SCPD. Immunofluorescence in PE-DIF was rapidly deteriorating than in FF-DIF. Conclusions DIF done on paraffin-embedded tissue can be used as a supplement and salvage technique with histopathology for the diagnosis of AIBDs, particularly when a cryostat facility for frozen tissue is not available and the patient is unable to undergo a second biopsy procedure.

Multiple Bullous and Ulcers as Cutaneous Manifestations of Wegener's Granulomatosis: A Rare Case Report

Bullous dermatoses is a heterogeneous group of blistering skin disorders that can either be inherited or acquired. Subepidermal blisters may result in ulceration and scarring following their rupture. Wegener’s granulomatosis (WG) is a granulomatous necrotizing vasculitis affecting small- to medium-sized blood vessels. It is associated with anti-neutrophil cytoplasmic antibodies (ANCA) and can be manifested cutaneously as multiple bullous and ulcers. A case of WG was reported in an 18-year-old man presented with multiple skin bullous and ulcers. The patient was diagnosed with WG based on the findings from nasopharyngoscopy examination that revealed crusts in his nasal cavity; necrotizing granulomatous appearance on chest radiograph; hematuria on urinalysis; and positive ANCA blood test. This patient received a combination of methylprednisolone and methotrexate, resulting in improvement within four weeks of therapy. His multiple skin ulcers were treated with a combination of dialkyl carbamoyl chloride, hydrocolloid, and hydrogel dressings. This patient was in complete remission state after six months of treatment, which later followed by a relapse episode that occurred within one year. WG with multiple skin bullous and ulcers can mimic other diseases. Various examinations such as histopathology, direct immunofluorescence, and ANCA blood test may aid in determining the etiology of skin bullous and ulcers.

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.