[Paraneoplastic pemphigus: Retrospective study of a case series]

Paraneoplastic pemphigus (PNP) is a rare condition associated with poor prognosis. It associates polymorphic mucocutaneous manifestations with neoplasia. Diagnosis is difficult because of the various clinical and histological features involved and the lack of specificity of immunological examinations.

We retrospectively analyzed the records of patients presenting with PNP in the Poitou-Charentes region between 2000 and 2015.

Seven patients were included. They presented 9 neoplasias (1 lymphoma, 1 melanoma, and 7 carcinomas) diagnosed from 4 months before to 25 months after the occurrence of cutaneous (6/7) and/or mucosal (6/7) polymorphic lesions. Histological examination revealed epidermal acantholysis (7/7), keratinocytic necrosis (4/7), and interface lichenoid dermatitis (5/7). Intercellular deposits of IgG and C3 or along the dermo-epidermal junction were detected with direct immunofluorescence (IF) (7/7). Four of 6 patients tested had positive indirect IF on rat bladder epithelium. Follow-up ranged from 1-132 months with a one-year survival of 85.7%.

The clinical and histopathological presentations observed in our patients were polymorphic, with overlap between the clinical and histological features of PNP and classical pemphigus. Prognosis and survival appear better in our series than in the literature. It is possible that in some cases, the association of pemphigus with neoplasia was fortuitous, which might account for the better prognosis. A new consensus on the diagnostic criteria for PNP is needed to help practitioners to consensually diagnose it for prognostic or therapeutic trials.