A typical carcinoid tumor of the lung presenting with pure persistent ground-glass opacity on high-resolution computed tomography: a case report
Pure ground-glass opacity nodules (p-GGN) on high-resolution computed tomography (HRCT) generally have been considering typically associated with adenocarcinoma with less invasive nature. We herein reported a patient presenting focal p-GGN on middle lobe of the right lung who underwent surgical resection with its pathological diagnosis turned out to be typical carcinoid tumor.
KeywordsLung typical carcinoid tumor Pure ground-glass opacity on chest computed tomography
Pure ground-glass opacity nodules (p-GGN) are frequently identified in the lung parenchyma on high-resolution computed tomography (HRCT). The pathology of p-GGN on HRCT was reported to be atypical adenomatous hyperplasia (AAH), adenocarcinoma, focal organizing pneumonia/fibrosis  and so on. In order to determine a malignant or benign histology, surgical resection is sometimes required.
We herein report a case of a resected typical carcinoid tumor that presented as a persistent p-GGN on HRCT.
The term “ground glass opacity (GGO)” is defined as “hazy increased attenuation in the lung that does not obliterate the bronchial and vascular margins” in the lung detected on HRCT, according to the Fleischner Society . This definition is non-specific and does not necessarily reflect the pathological etiology of p-GGN. The presence of p-GGN on HRCT sometimes implies early-stage lung cancer, i.e. adenocarcinoma in situ or so-called bronchioloalveolar adenocarcinoma . With respect to other lung malignancies, Okita et al. reported a rare case of metastatic melanoma in the lung presenting with focal GGO . To our knowledge, this is the first report of a typical carcinoid tumor of the lung that presented with focal p-GGN on HRCT. In general, the appearance of a typical carcinoid tumor on CT is generally a solid nodule . Also, diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is now considered to be a precursor for pulmonary carcinoid tumors; however, its appearance on HRCT has generally reported to be diffuse, multifocal GGO due to small airways obstruction evidenced by inspiratory mosaic attenuation and expiratory air trapping . In the present case, the tumor was consisted of many small scattered tumor foci even in the central collapsed area (Fig. 1b); thus, the appearance of the tumor on HRCT might have a possibility to be p-GGN.
In conclusion, despite its rarity, physicians should consider typical carcinoid tumors in the differential diagnosis of persistent p-GGN on HRCT.
No funding is present for this case report.
YM wrote this case report, and the rest authors equally contributed to this case report. All authors read and approved the final manuscript.
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The National Kyushu Cancer Center had written informed consent for scientific activity including writing case report with this patient described in this case report.
The authors declare that they have no competing interests.
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