PMC9649939_01
Computed tomography (CT) shows a 9-cm mass shadow in the middle lobe of the right lung (arrow) and right pleural effusion (A, B). CT at 5 months before admission shows an infiltrative shadow (C) and a 2.5-cm nodule shadow in the middle lobe (arrow) (D).
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Computed tomography (CT) revealed a 9-cm mass shadow in the middle lobe of the right lung and right pleural effusion (Fig. 1A and B). CT indicated middle lobe syndrome and exacerbation of the right middle lobe infiltrative shadow (Fig. 1C) compared with findings 5 years prior. At that time, a nodule shadow was also observed in the right middle lobe (Fig. 1D).
Surgical view showing the middle lobe tumor and rupture site (arrow) (A). Photomicrograph of hematoxylin and eosin stained tissue (B-E). The tumor is comprised of round-to-short spindle tumor cells with eosinophilic cytoplasm and frequent mitoses (arrow) ( x 400) (B). The tumor is in the lung parenchyma and has infiltrated into the peripheral alveolar walls ( x 40) (C). Intratumoral hemorrhage (black arrow) and ischemic necrosis lesions (white arrow) are shown. (scale bar: 10 mm) (D). Epithelioid granulomas with caseous necrosis are present near the tumor ( x 100) (E).
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The site of the tumor rupture with bleeding was confirmed in the vicinity of the adhesion detachment (Fig. 2A). Histological examination revealed that the tumor comprised round-to-short spindle tumor cells with fascicular and storiform patterns (Fig. 2B). The tumor was present in the lung parenchyma (Fig. 2C) and was considered a lung tumor. Intratumoral hemorrhage (Fig. 2D) as well as vessel and mediastinal adipose tissue invasion were confirmed. Epithelioid cell granulomas with caseating necrosis were found near the tumor (Fig. 2E).
Photomicrograph of an immunohistochemically stained section showing that a lung tumor positive for vimentin (A), weakly positive for AE1/AE3 (B) and calretinin (C), and negative for CK5/6 (D) ( x 400).
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Immunohistochemical staining showed that the lung tumor cells were strongly positive for vimentin, weakly positive for AE1/AE3 and calretinin, and negative for TTF-1, CEA, p40, CK5/6, D2-40, and CD34 (Fig. 3A-D).