Paraneoplastic bullous pemphigoid in association with squamous cell carcinoma of the lung: A case report and literature review

Abstract

Bullous pemphigoid (BP) is a common autoimmune subepidermal blistering disorder that predominantly affects the elderly and is characterized by autoantibodies against BP230 and BP180. While its aetiology remains uncertain, BP has been associated with medications, infections, and neoplasms, including paraneoplastic manifestations. This report highlights a rare case of paraneoplastic BP in a 72-year-old male with squamous cell carcinoma (SCC) of the lung, emphasizing the importance of recognizing BP as a potential cutaneous marker of internal malignancies. The patient presented with itchy, tense blisters on an erythematous base, erosions, and crusts, confirmed as BP through immunopathological testing. Imaging revealed a lung tumour, later diagnosed as SCC with mediastinal and right hilar lymphadenopathy. Despite topical steroid treatment for BP and subsequent oncologic consultations, the patient’s condition progressed. The skin lesions exacerbated alongside the malignancy, and he was eventually referred to the hospital again. This case underscores the potential paraneoplastic nature of BP and its association with lung SCC, which remains poorly understood. Notably, recent reports indicate that BP may resolve following successful cancer treatment, further suggesting a pathogenic link. However, therapeutic challenges persist, particularly in cases of advanced malignancy or treatment resistance. Innovative therapies, such as omalizumab and Janus kinase inhibitors, have shown promise in managing refractory BP, including cases induced by immune checkpoint inhibitors. Clinicians should consider comprehensive cancer screening in patients with refractory BP, as early identification of associated malignancies may improve outcomes. Further studies are warranted to elucidate the underlying mechanisms connecting BP and neoplasms, refine diagnostic approaches, and expand treatment options. This case contributes to the growing evidence of BP as a paraneoplastic phenomenon, particularly in the context of SCC.