PMC6290381_01
Contrast-enhanced computed tomography demonstrating a protuberant tumor in the lumen of the left main bronchus (arrow).
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Chest CT revealed a tumor, 13 mm in size, in the inlet of the left main bronchus (Fig. 1), and an 8 mm nodule in the lingular segment of the left lung.
Positron emission tomography/computed tomography revealing higher accumulation of 18F-fluoro-2-deoxy-d-glucose in the lumen of the left main bronchus (maximum standardized uptake value = 4.1) coinciding with tumor (arrow).
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PET/CT revealed abnormal FDG uptake (maximum standardized uptake value, 4.1) in the left main bronchus tumor, but not in the palpebral conjunctiva, with no other abnormal uptake (Fig. 2).
Bronchoscopic view revealing multiple polypoid-surface tumors on the luminal surface of the left main bronchus.
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Subsequent flexible bronchoscopy revealed a polypoid tumor in the left second carina, in which mucosal edema and over-swelled blood vessels were observed (Fig. 3).
(A) Histological findings from the palpebral conjunctival lesion. Diffuse proliferation of atypical lymphoid cells reaching the palpebral conjunctival epithelium (hematoxylin-eosin stain, original magnification x40). (B) Small- and medium-size atypical lymphocytes infiltrating the adrenal glandular epithelium, forming lymphoepithelial lesions (arrow) (hematoxylin-eosin stain, original magnification x400). (C) Histological findings from the bronchial lesion. Diffuse proliferation of atypical lymphoid cells surrounding the lymphoid follicles (hematoxylin-eosin stain, original magnification x100). (D) Small- and medium-size atypical lymphocytes infiltrating the bronchial epithelium, forming lymphoepithelial lesions (arrow) (hematoxylin-eosin stain, original magnification x400). (E) Immunohistochemical staining for CD79a was strongly positive in lymphocytic tumor cells infiltrating under the bronchial mucosa (CD79a stain, original magnification x200). (F) Immunohistochemical staining for BCL-2 was also positive in lymphocytic tumor cells infiltrating under the bronchial mucosa (BCL-2 stain, original magnification x200).
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The histological appearance of the bronchus tumors were similar to past palpebral conjunctival MALT lymphoma (Fig. 4A-D). Immunohistochemical staining of the bronchial tumor was positive for CD79a, CD20, and BCL-2 (Fig. 4E and F), and negative for CD3, CD5, CD10, and cyclin D1; the expression of kappa-to-lambda ratios were not significant.