Exceptional Response in BRAF p.V600E-Mutant Enteric-Type Adenocarcinoma of the Lung With Cutaneous Spread: A Case Report

Background: Enteric-type adenocarcinoma of the lung (lung-ETAC) is a rare form of lung cancer with histologic similarities to colorectal cancer, with aggressive behavior and unfavorable prognosis. Case presentation: An 81-year-old man presented with discolored skin lesions on the chest and abdomen. After comprehensive evaluation, including skin biopsy and molecular profiling, the patient was diagnosed with having lung-ETAC with a BRAF p.V600E mutation. Treatment with dabrafenib and trametinib initially resulted in positive results, with improvement in skin lesions and overall clinical condition. Nevertheless, approximately 6 months after, the disease had progression with new skin lesions reappearing. Conclusions: We reported a unique case of a patient with BRAF p.V600E-mutant lung-ETAC with metastatic skin lesions achieving complete cutaneous response after targeted treatment with dabrafenib and trametinib, highlighting the potential for targeted therapy in patients with lung-ETAC harboring a BRAF p.V600E mutation.