Paraneoplastic pemphigus involved oral mucosa only: a case report and literature review

Abstract

Paraneoplastic pemphigus (PNP) is a rare and potentially fatal autoimmune disease that primarily affects the mucocutaneous tissues. Here we present the clinical features of a patient with the lichenoid variant of PNP involving the oral mucosa only. The patient exhibited clinical manifestations resembling both lichen planus and pemphigus, yet these lesions remained unresponsive to corticosteroid therapy. A chest computed tomography (CT) scan revealed Castleman disease. Following surgical removal of the tumor, the patient's oral mucosa healed completely, with no recurrence observed in a 4-year follow-up period. These findings emphasize the importance of considering PNP as a potential diagnosis in patients with refractory oral erosions displaying lichen planus-like and pemphigus-like features, particularly when unresponsive to corticosteroid therapy. A thoracic-abdominal-pelvic CT scan is recommended to facilitate accurate diagnosis and appropriate treatment.

Keywords: autoantibodies; autoimmune disease; neoplasms; oral mucosa; paraneoplastic pemphigus.

FIGURE 1

(A–I) Mucosal physical examination: diffuse erosive stomatitis. (A–C) Scattered vesicles on the red mucous membranes of the upper and lower lips. (D–F) Extensive vesicles and congestion of the mucous membranes of the ventral and dorsal part of the tongue bilaterally. (G–I) Extensive vesicles and exudate on the buccal mucous membranes.

FIGURE 2

(A–G) Histopathological and imaging findings. (A) Dense lymphocytic infiltration within the epithelium (“mossy appearance”) with liquefactive degeneration of basal cells, indicative of interfacial dermatitis. (B) Basal cell liquefaction accompanied by dense lymphocytic infiltration. (C) Clarification needed: “Untwisting of the vertebral column”—consider specifying histopathological or structural relevance, as this phrase seems out of context for histology. (D) Cellular degeneration and keratinization surrounded by peripheral lymphocytic infiltration. (E,F) Direct immunofluorescence (DIF): Negative for intercellular deposits of IgG and C3. (G) PET/CT imaging: a soft tissue mass on the right side of the upper mediastinum and trachea with mild FDG metabolic activity.

FIGURE 3

(A–F) Complete healing of oral mucosa after surgery. (A) The original vesicles of the red lip mucosa healed completely from before. (B) The vesicles of the dorsal tongue mucosa and the ventral tongue mucosa healed completely from before. (C–D) The original vesicles of the buccal mucosa healed completely from before, and the exudation disappeared. (E–F) Other mucosal erosions of the oral cavity have completely healed from the previous condition.