PMC7232110_01
Radiological Findings. [A] posterior-anterior plain chest film obtained 2 weeks prior to presentation with tracheal deviation to the right and hilar fullness. [B] Chest CT scan with contrast with axial view with right mainstem obstructing endobronchial mass (yellow arrow) [C] Coronal reconstruction with right mainstem endobronchial mass (yellow arrow) with evidence of post obstructive bronchiectasis. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
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The patient had been seen for the same complaint at an outside primary care clinic two weeks prior and a chest X ray revealed a mild tracheal deviation to the right (Fig. 1A). A computed tomography (CT) of the chest with contrast was obtained (Fig. 1B & C) and it was notable for a 1.9 cm mass in the right mainstem bronchus with associated right lower lobe consolidation and bronchiectasis.
Bronchoscopy Findings. [A] A 90% obstructing mass (circumferential, endobronchial, exophytic, and polypoid) in the proximal right mainstem bronchus and bronchus intermedius. [B] Right mainstem bronchus after airway recanalization.
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The mass was large and circumferential, endobronchial, exophytic, and polypoid (Fig. 2A). Finally, balloon dilation was performed in the right mainstem bronchus and bronchus intermedius (Fig. 2B).
Pathology Findings. [A] The tumor demonstrates an irregular, infiltrative pattern within a fibrotic stroma. [B] In the tumor nests, there are ducts that are tightly coupled to a surrounding layer of myoepithelial cells with pale cytoplasm. [C] The myoepithelial cells are positive for p40, while the ducts are not. [D] CD117 shows the opposite pattern, with staining seen only on the luminal surface of the inner ductal cells.
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Microscopic evaluation (Fig. 3) showed an infiltrating gland-forming neoplasm with two cell components: eosinophilic ducts, tightly coupled with a surrounding layer of myoepithelial cells with clear cytoplasm. Immunostains (Fig. 3) highlighted the two cell components, as the ducts were positive for AE1/AE3 and CD117 while the myoepithelial cells stained for SOX10, S100, p40 and p63.SMA was negative.