Paraneoplastic Pemphigus

Etiology • Autoimmune, triggered by malignant or benign tumors • Autoantibodies directed against a variety of epidermal antigens
including desmogleins 3 and 1, desmoplakins I and II, and other desmosomal antigens, as well as basement membrane zone antigens
Clinical Presentation • Short-lived vesicles and bullae followed by erosion and ulcera-
tion; resembles oral pemphigus • Multiple oral sites • Severe hemorrhagic, crusted erosive cheilitis • Painful lesions • Cutaneous lesions are polymorphous; may resemble lichen
planus, erythema multiforme, or bullous pemphigoid • Underlying neoplasms such as non-Hodgkin’s lymphoma,

leukemia, thymoma, spindle cell neoplasms, Waldenström’s macroglobulinemia, and Castleman’s disease
Microscopic Findings • Suprabasilar acantholysis, keratinocyte necrosis, and vacuolar
interface inflammation • Direct immunofluorescent testing is positive for epithelial cell
surface deposition of IgG and C3 and a lichenoid tissue reaction interface deposition pattern
• Indirect immunofluorescent testing is positive for epithelial cell surface IgG antibodies
• Special testing with mouse and rat bladder, cardiac muscle, and liver may demonstrate paraneoplastic pemphigus antibodies that bind to simple columnar and transitional epithelia
Diagnosis • Biopsy of skin or mucosa • Direct immunofluorescent examination of skin or mucosa • Indirect immunofluorescent examination of sera including
special substrates
Differential Diagnosis • Pemphigus vulgaris • Erythema multiforme • Stevens-Johnson syndrome • Mucous membrane (cicatricial) pemphigoid • Erosive oral lichen planus
Treatment • Identification of concurrent malignancy • Immunosuppressive therapy
Prognosis • Good with excision of benign neoplasms • Grave, usually fatal, with malignancies • Management is very challenging.