Mucous membrane pemphigoid (MMP), likely thymoma-associated/paraneoplastic.
Bx demonstrated subepithelial clefting with a predominantly neutrophilic infiltrate, and DIF showed linear IgG deposition along the BMZ w/out intercellular staining, supporting MMP and arguing against paraneoplastic pemphigus.
The patient’s severe multisite mucosal involvement (oral, ocular, nasal, esophageal, & genital) improved rapidly w/ systemic corticosteroids & recurred w/ thymoma progression, suggesting a paraneoplastic MMP-like autoimmune blistering disorder associated w/ thymoma.
Although chemotherapy-induced mucositis, infection, & paraneoplastic pemphigus were initially considered, the clinicopathologic findings & steroid responsiveness favored MMP.
A woman in her 60s w/ a hx of type B2 thymoma (s/p resection & adjuvant chemo) developed progressive, painful oral ulcerations during tx w/ carboplatin & etoposide. She also reported dysphagia, nasal obstruction, & painful genital erosions.
O/E: extensive erosions, crusting, & scale of the lips, multiple buccal mucosal ulcers, & B/L conjunctivitis.
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