Usefulness of a Simple Immunohistochemical Staining Technique to Differentiate Anti-p200 Pemphigoid From Other Autoimmune Blistering Diseases: A Report of 2 Cases. / Descripción de 2 casos de penfigoide anti-p200. Utilidad de una técnica inmunohistoquímica sencilla en el diagnóstico diferencial con otras enfermedades ampollosas autoinmunes.

Anti-p200 pemphigoid is a rare autoimmune subepidermal blistering disease characterized by the presence of circulating immunoglobulin G antibodies directed against laminin gamma-1, a 200-kDa protein located in the lamina lucida of the basement membrane. We review the clinical, histopathological and immunological characteristics of the first 2 cases described in Spain. Anti-p200 pemphigoid shares histopathological and immunopathological findings with epidermolysis bullosa acquisita, the main entity in the differential diagnosis. However, its management follows the same guidelines as those used for bullous pemphigoid. The diagnosis is confirmed by immunoblotting, which is a complex technique available in few centers. We propose the immunohistochemical detection of collagen type IV on the floor of the blister, combined with standard immunofluorescence techniques, as a simple, accessible alternative to differentiate anti-p200 pemphigoid from epidermolysis bullosa acquisita.

γδ T-cell-rich variants of pityriasis lichenoides and lymphomatoid papulosis: benign cutaneous disorders to be distinguished from aggressive cutaneous γδ T-cell lymphomas.

BACKGROUND: T cells with a γδ phenotype have been associated with aggressive lymphomas. Yet, inflammatory skin disorders and low-grade lymphoproliferative disorders have rarely been described with a predominant γδ T-cell infiltrate. OBJECTIVES: To review our experience and determine the clinical relevance of the γδ T-cell phenotype in lymphomatoid papulosis (LyP) and pityriasis lichenoides (PL). METHODS: A retrospective dermatopathology file review looking for LyP and PL characterized by a γδ T-cell phenotype was performed. Clinical manifestations and course, histological features and molecular data were analyzed. RESULTS: Six of 16 cases of LyP and four of 23 cases diagnosed as PL during a 5-year period (2009-14) were identified. The median follow-up for the whole group was 16 months (range 3-64), showing an indolent clinical course in all cases. CONCLUSIONS: The detection of a predominantly γδ T-cell phenotype in papular lymphoid-rich infiltrates in the absence of other lesions is not associated with a clinically aggressive course. γδ T-cell-rich variants of LyP and PL may reflect a spectrum of related conditions. This is a single academic centre retrospective chart review of a relatively small sample.