PMC8794385_01
Contrast-enhanced CT-image at the level of the mediastinum shows a heterogeneous mass in the prevascular mediastinum with a more solid component in the cranial part (A) and fatty component in the more inferior part of the mass (B). Also note small foci of calcifications (B). Coronal image (C) clearly shows the heterogeneity of the mass.
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The mass showed areas with different densities, including a soft tissue component, areas with negative Hounsfield units (HU) consistent with fat, and some foci of calcification (Figure 1).
Axial contrast-enhanced CT-image at the level of the hilar region shows an enlarged (short axis 11 mm) round and slightly heterogeneous lymph node.
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A hilar adenopathy was noted on the right side (station 10R) (Figure 2).
Anatomical pathology of the surgical specimen shows (A) macroscopically residual thymus (single arrow) and a relatively well defined 13 cm large mass with a denser component (arrowheads). (B) Detail of the mass (mature teratoma) showing sebaceous material and hair. (C) Photomicrograph (Hematoxylin-eosin stain, original magnification x20) shows part of the residual thymus (white arrow) as well as a tumor composed of irregular sheets and glandular structures, consistent with a poorly differentiated adenocarcinoma from an intestinal type (yellow arrows). Also note the associated glandular structures with mucin (green arrow). Histopathologic examination (not shown) of the hilar adenopathy showed the same findings as the tumor component of the mediastinal mass.
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The histopathological examination of the excised tumor (with measurements 8.0 cm x 3.0 cm x 13.0 cm) showed residual thymus and a relatively well defined large mass with a more dense component (Figure 3A). Macroscopic examination showed sebaceous material and hair, indicating the diagnosis of a mature teratoma (Figure 3B). Photomicrograph (Hematoxylin-eosin stain, original magnification x20) shows part of the residual thymus as well as a tumor composed of irregular sheets and glandular structures, consistent with a poorly differentiated adenocarcinoma from an intestinal type (Figure 3C).