Pleomorphic Lung Carcinoma Response to Treatment With BRAF and MEK Inhibitors: A Case Report.

Pleomorphic carcinoma is one of the most difficult non-small cell lung cancers to treat with cytotoxic agents. Early recurrence after pulmonary resection is common, and the prognosis is poor. Herein, we report a case of pleomorphic carcinoma effectively treated via molecular targeting. An 80-year-old man relapsed within six months of undergoing left lower lobectomy for pathological stage IIB pleomorphic carcinoma. The initial treatment consisted of carboplatin, pemetrexed, and pembrolizumab, together with opioids (for severe pain due to pleuritis carcinomatosis and bone metastasis) and home oxygen therapy. Following the detection of a BRAF mutation (V600E) via whole-genome sequencing, the treatment was switched to dabrafenib (a BRAF inhibitor) and trametinib (a MEK inhibitor). One month later, the previously observed pleural effusion disappeared, and the radiological pulmonary findings were normal. The patient's pain diminished, the opioid dose was reduced, and home oxygen therapy was discontinued. This condition was maintained for approximately nine months; however, the patient died 11 months after treatment. Although controlling pulmonary pleomorphic carcinoma is challenging, the present case illustrates the effectiveness of BRAF and MEK inhibitors in cases with BRAF mutations, even those involving octogenarians.