Bullous pemphigoid associated with squamous cell lung carcinoma showing remarkable response to carboplatin-based chemotherapy:  a case report

BACKGROUND: Bullous pemphigoid is an uncommon dermatologic manifestation seen in squamous cell lung cancer, and evidence guiding optimal treatment, especially in the elderly population, is limited. We report herein a case of squamous cell lung cancer diagnosed after being investigated for refractory bullous pemphigoid showing marked response to carboplatin-based chemotherapy. This is the first case report that shows carboplatin can be used as an effective alternative in treatment of malignancy-associated bullous pemphigoid. CASE REPORT: An 80-year-old caucasian man developed extensive vesiculobullous rashes on his trunk, chest, abdomen, and inguinal region associated with significant pruritus causing sleep disturbance. The diagnosis of bullous pemphigoid was confirmed on skin biopsy. The skin lesions continued to worsen even after use of oral and topical steroid in addition to oral doxycycline. Chest computed tomography revealed a spiculated left lung lesion along with mediastinal lymphadenopathy. Fine-needle aspiration from the mediastinal lymph node confirmed metastatic squamous cell lung carcinoma. Carboplatin with gemcitabine was initiated, and significant response was seen within 3 days of chemotherapy. The skin lesions continued to remain in remission even after stopping the chemotherapy. CONCLUSION: Although there are still controversies regarding paraneoplastic etiology of bullous pemphigoid, this case presents a temporal association. It is the first case report showing a remarkable response with the use of a carboplatin-based regimen.