Primary adenoid cystic carcinoma of the trachea: an elusive diagnosis of chronic dyspnoea

Abstract

Primary adenoid cystic carcinoma (ACC) of the trachea is a rare entity, with a 5-year survival between 50% and 80% for resectable cases and 30% in case of unresectable disease. We report a case of a primary ACC on a woman in her 70s that presented with a drawn-out history of dyspnoea. She was diagnosed with an unresectable obstructive tumour of the trachea, which required the placement of a Y-shaped stent. The patient underwent concomitant chemoradiotherapy, with partial response, and is still in follow-up, without evidence of disease progression.

Keywords: Oncology; Radiotherapy; Respiratory cancer.

Figure 1

CT scan images showing an infracarinal prevertebral mass with 65×44 mm, involving the major bronchi bifurcation.

Figure 2

Histological sections of the ACC of the trachea. Beneath the respiratory mucosa, there is infiltration of a biphasic tumour arranged in tubular (A), solid (B) and cribiform (C) patterns, lined by epithelial and myoepithelial cells. These cells are clinged to a thickened basement membrane, which forms pseudolumina (D); focally, there is mucous production (E). AB, Alcian blue; ACC, adenoid cystic carcinoma; PAS/D: Periodic acid-Shiff with diastase.

Figure 3

Post-treatment evaluation thoracic CT scan (performed 8 weeks after treatment conclusion), evidencing an expansive lesion with 43×21 mm involving the posterior tracheal wall, extending to the carina with involvement of the major bronchi bifurcation—partial response (RECIST 1.1 criteria). Follow-up thoracic CT scan performed in March 2022, showing stable (RECIST 1.1 criteria) although still unresectable disease.