Direct immunofluorescence analysis of oral Tzanck smears for pemphigus vulgaris: A diagnostic test

Direct immunofluorescence demystified: Essential insights and recent advances for dermatologists

Direct immunofluorescence (DIF) is widely used in dermatopathology for the diagnosis of autoimmune blistering diseases (AIBDs), cutaneous vasculitis, and connective tissue disorders. Although it is easy and useful to perform, it needs technical expertise and experience for proper interpretation. The yield of DIF depends on multiple factors including the adequacy, transportation, storage, processing, and interpretation of the biopsy specimen. Effective collaboration between the dermatologist and dermatopathologist along with meticulous clinico-pathological correlation is crucial for accurately interpreting DIF in the appropriate clinical context. In this narrative review of DIF in dermatology, we discuss the indications of DIF, recent updates on the selection of optimum biopsy sites, basic techniques of DIF including the classical transport medium and its alternatives, processing and staining technique, patterns in various diseases, advancements such as serration pattern analysis, and latest recommendations on the use of DIF in cutaneous disorders.

Liquid-based cytology for differentiating two cases of pemphigus vulgaris from oral squamous cell carcinoma

Pemphigus vulgaris (PV) is a rare autoimmune disease characterized by blisters on the skin and mucous membrane. Since it often appears in the oral mucosa first, it may be diagnosed by oral mucosal cytology. Although the cytologic finding is characterized by acantholytic cells, that is, Tzanck cells, it is important to distinguish PV from neoplastic lesions of the oral mucosal epithelium, including differentiation from atypical parabasal/basal cells, which appear in squamous cell carcinoma (SCC). In this study, we examined the cellular findings in two cases of PV and a case of well-differentiated SCC with loss of epithelial cell cohesion. The samples were prepared using liquid-based cytology, which showed small round-shaped and deeply stained atypical, orangeophilic keratinocytes not only in SCC but also in PV, which made differentiation between the two difficult. However, Tzanck cells found in PV differ from the deep atypical parabasal/basal cells of SCC, suggesting that the cell outline is indistinct and small protrusions and brush-like structures are observed. This feature of Tzanck cells may be useful in cytological judgment.

Identification of oral immune disorders- A review and a diagnostic algorithm

Immunological disorders are observed in various clinical presentations in the oral cavity. The pathophysiology of these disorders include but are not limited to primary oral auto-immune disease, systemic disease with oral findings, malignancies, hypersensitivity reactions, drug-induced, and infection-related. Many of these disorders have overlapping oral features, making it difficult for the clinician to diagnose and treat the disorder. There is a need to provide a simple and practical decision-making algorithm to the clinicians and provide them guidance on laboratory investigations. The present review provides a diagnostic algorithm that might minimize outpatient process delays and lead to early management. This is crucial in many cases where oral findings may be the first sign of the disorder, and early treatment can preclude dissemination and complications of the disorder.