PMC9940310_01
(A, B) Chest CT scan showing an irregular soft tissue density mass (yellow arrow) on the right side of the anterior mediastinum that compressed the adjacent right lung (blue arrow), accompanied by pleural effusion (white arrow). (C, D) Contrast-enhanced chest CT scan showing that the mass had moderately uneven enhancement, which invaded the right lung (blue arrow), and the mediastinal lymph nodes were enlarged (red arrow). (E, F) The coronal multiplanar reconstruction images clearly delineated the irregular and uneven density mass on the right side of the anterior mediastinum with invasion of the superior vena cava (red arrow), pericardium (black arrow) and right lung (blue arrow).
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He went to the emergency department of the hospital 1 day prior because of chest tightness, and plain chest CT showed a mass on the right side of the anterior mediastinum that compressed the adjacent right lung, accompanied by pleural effusion ( Figures 1A, B ). The preoperative contrast-enhanced CT scan showed a giant cystic and solid mass on the right side of the anterior mediastinum, which had moderately uneven enhancement, and the mediastinal lymph nodes were enlarged ( Figures 1C, D ). The mass on the right side of the anterior mediastinum with invasion of the superior vena cava, pericardium and right lung could be observed from the coronal multiplanar reconstruction images ( Figures 1E, F ).
(A) Histopathological image showing tumor cells composed of primitive small round cells (H&E staining). (B, C) Immunohistochemical images showing positivity for CD99 and desmin. (D) Histopathological image showing pericardial effusion, which consisted of poor differentiation of malignant tumors.
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The pathological findings confirmed that it was a small round cell malignant tumor ( Figure 2A ). The immunohistochemical results demonstrated a Ki-67 of 90%, positivity for AE1/AE3, P16, CD 99 ( Figure 2B ), CD56 and synaptophysin, partial positivity for EMA, MDM2 and desmin ( Figure 2C ), and negativity for vimentin, CK7, CAM5.2, SMA, NSE and S-100. Finally, pathological examination of the pericardial effusion confirmed that it had malignant tumor cells ( Figure 2D ).