Paraneoplastic pemphigus. A report of two cases associated with chronic B-cell lymphocytic leukaemia

Paraneoplastic pemphigus (PNP) is an autoimmune blistering and erosive mucocutaneous disease associated with neoplasia. Clinical manifestations are polymorphous, and include erythema, bullae, erythema multiforme-like lesions and severe mucous membrane involvement. PNP manifesting as lichenoid dermatitis has recently been observed. We describe two Italian men with fatal PNP featuring typical PNP autoantigens associated with chronic B-cell lymphocytic leukaemia. The first patient presented with an extensive blistering eruption, several erythema multiforme-like lesions and severe mucosal involvement. The second patient presented with a lichenoid dermatitis, then developed bullae, and died with an erythrodermic and exfoliative dermatosis resembling pemphigus foliaceus. Our patients represent two Italian cases of well-documented PNP. In patient 2, the sequence of clinical presentations was unique, and strongly supports the hypothesis of epitope spreading through chronic lichenoid inflammation of the dermo-epidermal junction exposing new self antigens, leading to the humoral response characteristic of PNP.