A Rare Case of PD-L1 Positive Adenoid Cystic Carcinoma of the Trachea

Document Type

Article

Abstract

INTRODUCTION: Adenoid Cystic Carcinoma (ACC) is a malignancy known for originating in the salivary glands, though rarely, it can originate in trachea. In a 2021 review, cases reported were noted to be program death ligand 1 (PD-L1) negative. We present an atypical case of tracheal ACC that was PD-L1 positive in an otherwise healthy patient presenting with hemoptysis.

CASE PRESENTATION: A 46-year-old male with no significant past medical history presented with a chief complaint of of hemoptysis. He denied fevers, chills, night sweats, weight loss, shortness of breath, or cough. He had no significant smoking history, tuberculous exposure, or sick contacts. Surgical history was notable for lumbar spinal fusion ten years prior, of which there were no documented complications with anesthesia or endotracheal tube placement. A CT scan of the chest revealed a 25mm x 21mm x 25mm lesion noted along the posterior trachea that extended within the lumen. The patient underwent bronchoscopy with endobronchial biopsy of the tracheal lesion. Pathological assessment of the tracheal lesion revealed adenoid cystic carcinoma. Subsequent brain MRI and positron emission tomography (PET) of the skull base to mid-thigh yielded no evidence of metastatic disease. Immunohistochemistry staining was positive for program death ligand 1 (PD-L1). The patient underwent distal tracheal resection and reconstruction and adjuvant radiotherapy.

DISCUSSION: Adenoid cystic carcinoma is a malignancy of the submucosal glands that can originate from the trachea. In addition to the low incidence of ACC, PD-L1 expression in identified cases has not been found to be common. In a 2015 study of ACC immunological profiling, PD-L1 was not identified in 28 samples of ACC. In a 2023 study investigating PD-L1 expression in lung malignancies, it was found that only 3.7% of ACC tumor samples were positive for PD-L1. Despite 80% PD-L1 expression, surgical resection and adjuvant radiation was the elected modality of therapy, of which our patient had excellent results.

CONCLUSIONS: Adenoid cystic carcinoma of the trachea is a submucosal gland tumor that rarely can originate in the trachea. Only recently have there been reports of PD-L1 expression. Surgical resection remains the primary treatment modality, however studies regarding the utility targeted therapy with PD-L1 checkpoint inhibitors in this population are needed.

First Page

A4161

DOI

10.1016/j.chest.2024.06.2526

Publication Date

10-1-2024

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