Suspected NUT carcinoma progressing on pembrolizumab, carboplatin, and paclitaxel as first-line treatment: a case report.

INTRODUCTION AND IMPORTANCE: NUT carcinoma of the thorax is an extremely rare neoplasm characterized by a translocation between the NUT M1 gene and members of the bromodomain genetic family. Due to the rarity of the neoplasm, standardized treatment guidelines have not yet been established. Several chemotherapeutic agents have been used with limited success, due to the rapid development of resistance to treatment. Pembrolizumab, an anti-programmed-death-1 antibody, has become increasingly used in non-small-cell lung carcinomas. Consequently, pembrolizumab may be beneficial in the treatment of NUT carcinoma.

CASE PRESENTATION: In this article, we discuss the case of a 24-year-old man who was referred to our centre due to an incidental mass finding on an unrelated computed tomography scan. Morphological and immunohistochemical characteristics are highly suspicious of NUT carcinoma with bone metastasis. The patient was placed on carboplatin, paclitaxel, and pembrolizumab as first-line therapy. The patient later progressed and began receiving second-line treatment according to Ewing's protocol. 20 months later, the mass continued to grow, and the patient was started on docetaxel and gemcitabine, which was unsuccessful. After discussing with the patient, he decided to stop chemotherapy and begin palliative care.

CLINICAL DISCUSSION: NUT carcinoma is an aggressive tumour with poor prognosis. Treatment options are limited and pembrolizumab does not seem to influence the clinical outcome of the neoplasm.

CONCLUSION: Overall, pembrolizumab does not seem to improve the outcomes of NUT carcinoma patients. To the authors' knowledge, this is the second article reporting the effects of pembrolizumab on the progression of NUT carcinoma.