Anti‐ BP180 Mucosal Membrane Pemphigoid With a History of Maxillary Carcinoma With Antibodies to 190  kDa Periplakin and 210  Mami Kishimoto, Marie Ohata, Haruki Jimbo, Takashi Hashimoto, Takeshi Fukumoto

ABSTRACT

Mucous membrane pemphigoid (MMP) primarily affects the mucosal surfaces with minimal skin involvement. Approximately 70% of MMP cases show positivity for anti‐BP180 antibodies. Paraneoplastic pemphigus (PNP) typically presents with antibodies against periplakin and envoplakin. We report a case of anti‐BP180 MMP with a past history of maxillary carcinoma showing immunoblot positivity for 190 kDa periplakin and 210 kDa envoplakin. A 64‐year‐old man presented with recurrent oral erosions and later developed widespread mucocutaneous lesions. Histopathological examination revealed subepidermal blisters with mixed inflammatory cell infiltration. Direct and indirect immunofluorescence revealed immunoglobulin (Ig) G and C3 deposition in the basement membrane zone, and split‐skin indirect immunofluorescence revealed localized IgG in the epidermis. Immunoblotting revealed reactivity to the BP180 C‐terminal domain, periplakin, and envoplakin, whereas chemiluminescence enzyme immunoassay yielded negative results for Dsg1, Dsg3, and BP180. Enzyme‐linked immunosorbent assay showed positive for BP180 and BP230 antibodies. The lesions improved with the administration of topical steroids, oral minocycline, and nicotinamide. Although periplakin and envoplakin antibodies are characteristic of PNP, their persistence despite clinical improvement suggests nonpathogenicity in this case. The clinical course and disappearance of anti‐BP180 C‐terminal antibodies suggest pathogenicity. Maxillary carcinoma, a type of squamous cell carcinoma, may contribute to the generation of antiplakin autoantibodies.