PMC9160572_01
CT scan 2018- Homogeneous left adrenal mass with regular margins, (arrow), diameter of about 3 cm and a non-contrast CT density greater than 10 HU (A) not indicative of the presence of lipids. In the arterial (B) and venous (C) contrast phases, the mass presents a slightly heterogeneous appearance.
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F1
In 2018, a CT scan had revealed a left adrenal mass with a maximum diameter of 3 cm (Figure 1).
MRI scan 2019- Follow-up confirms the presence of a slightly enlarged, compared to the CT control, left adrenal solid mass. The T1 in-phase (IP) and out-of-phase (OOP) sequences (A,B) confirm a substantial absence of lipid content. The mass is rather homogeneous, isointense in T2 STIR (C, arrow), solid with restriction in the diffusion map (D). MRI scan 2020- A clear enlargement of the adrenal mass is present (maximum diameter about 5 cm), which is heterogeneously solid in the DWI map (E). Also in T2 w (F) the mass is larger and heterogeneous, in T1 w the mass has a parenchymal signal (G) with a slightly inhomogeneous post-contrast impregnation (H, venous phase).
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F2
At an MRI scan performed in 2019, the lesion showed a minimal size increase, and a wait-and-see strategy was decided (Figures 2A-D). Qualitative analysis of axial MRI images in and opposed-phase (Figures 2A,B) revealed no signal drop inside the lesion. T1, T2 and post contrast sequences (Figures 2E-H). The lesion exhibited uptake at 18F-FDG-PET scan, with a SUVmax adrenal/SUVmax liver ratio of 3.5 (Figures 3A,B).
(A,B). PET scan 2020- The images show a well-defined lesion (arrow) involving the left adrenal region that has a SUV average of 4.56 with an average -68bHU; SUV average is higher than the liver SUV, thus suggesting a malignant lesion. (C). Intraoperative picture. The normal adrenal gland is indicated by the arrow, whereas the surface of the oncocytoma by the asterisk.
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F3
T1, T2 and post contrast sequences (Figures 2E-H). The lesion exhibited uptake at 18F-FDG-PET scan, with a SUVmax adrenal/SUVmax liver ratio of 3.5 (Figures 3A,B). The normal adrenal gland, which was completely separated from the lesion was entirely spared (Figure 3C).
Histological assessment. Adrenocortical adenoma (A-C). The neoplasm was mainly composed of lipid-laden cells resembling those of normal zona fasciculata (A). The reticulin framework completely surrounded adrenal adenoma cells in small nests (B). Proliferation index (Ki-67) was lower than 1% (C). Adrenocortical oncocytoma (D-F). Oncocytic cells were characterized by granular eosinophilic cytoplasm and bland-appearing nuclei (D). The solid-alveolar pattern was better appreciated with reticulin stain (E). Ki-67 immunostaining labeled a very low number of neoplastic cells (F).
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F4
The revision of the histological sections obtained at the time of right adrenal surgery confirmed the previous diagnosis of adrenal adenoma (Figure 4).