Intravascular Pulmonary Artery Tumour Mimicking Nodal Recurrence and Inadvertently Sampled by EBUS ‐ TBNA : A Case Report

Figures

• 

  FIGURE 1. (A) Chest CT at initial presentation showing a 20‐mm nodule in the right upper lobe, consistent with primary lung adenocarcinoma. (B) Follow‐up chest CT 2 years after surgical resection demonstrating a newly appeared mediastinal mass adjacent to the right main pulmonary artery, initially interpreted as lymph node metastasis. (C) PET‐CT showing intense FDG uptake in the mediastinal mass. (D) CT obtained at disease progression confirming intraluminal extension of the tumour from the right main pulmonary artery toward the bifurcation, establishing the intravascular localization of the tumour.

• 

  FIGURE 2. (A) Endobronchial ultrasound (EBUS) image during the first needle pass showing a homogeneous hypoechoic mass at station 10R–11 s with sonographic features consistent with nodal recurrence, the presumed diagnosis at the time. No echo‐free space is visible deep to the mass. (B) EBUS image obtained during needle withdrawal on the second pass. The mass has been displaced superiorly toward the needle tip, revealing a wedge‐shaped echo‐free space deep to the mass (arrow) consistent with the pulmonary artery lumen. This finding suggests that the needle had engaged an intravascular structure, but was not recognised as significant at the time of the procedure. (C) Haematoxylin and eosin staining of the EBUS‐TBNA specimen showing high‐grade sarcomatous cells (original magnification ×200). Scale bar = 50 μm.

• 

  FIGURE 3. Immunohistochemical comparison between the primary lung adenocarcinoma and the recurrent intrapulmonary artery tumour (original magnification ×200). (A, B) TTF‐1 staining: Strong diffuse positivity in the primary tumour (A) and weak focal positivity in the recurrent lesion (B), consistent with partial loss of epithelial differentiation in the recurrent lesion. (C, D) h‐caldesmon staining: Negative in the primary tumour (C) and positive in the recurrent lesion (D), demonstrating de novo acquisition of smooth muscle differentiation. (E, F) Myogenin staining: Negative in the primary tumour (E) and positive in the recurrent lesion (F), demonstrating de novo acquisition of skeletal muscle differentiation. Scale bars = 50 μm for all panels.