Subcorneal pustular dermatosis an immnohisto-pathological perspective.

UNLABELLED: Subcorneal pustular dermatosis (SPD) represents a chronic, relapsing sterile pustular eruption, involving the trunk and flexoral proximal extremities. A 54-year-old female presented with recurrent, flaccid pustules measuring several millimeters in diameter, on normal and mildly erythematous skin of the groin and submammary areas. Biopsies for hematoxylin and eosin (H&E) examination, direct immunofluorescence (DIF) and immunohistochemistry (IHC) analysis were performed. The H&E staining demonstrated typical features of SPD, including some damage within dermal pilosebaceous units subjacent to the subcorneal blistering process. DIF revealed strong deposits of immunoreactants IgG, IgM, fibrinogen and complement/C3, present in a shaggy pattern within the subcorneal disease areas; in focal, areas of the basement membrane junction and in focal pericytoplasmic areas of epidermal keratinocytes. IHC revealed strong positivity to HLA-DPDQDR, mast cell tryptase, CD68, and ZAP-70 in the subcorneal inflammatory infiltrate, and surrounding dermal blood vessels. Myeloperoxidase was also positive. Positive staining with the anti-ribosomal protein S6-pS240 at the edges of hair follicles and sebaceous glands subjacent to the subcorneal blisters was also noted.
CONCLUSIONS: We conclude that this disorder may have several components in its etiopathology, including a possible restricted immune response and a possible genetic component; these possibilities warrant further investigation.