case_images: PMC11211248_01
case_images: Frontal (A) and axial (B) CT scans of the abdomen presenting a large lesion of the left adrenal gland. 18F-FDG-PET-CT presenting high metabolic activity of the left adrenal gland lesion (C1, C2) and metastatic bone lesions in the spine and sternum (D).
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case_images: PMC11211248_01_fendo-15-1399930-g001.jpg
case_images: f1
case_images: Computed tomography (CT) of the chest, abdomen, and pelvis was performed and revealed a left, inhomogeneous, solid adrenal mass measuring 80 mm x56 mm x39 mm of 25 Hounsfield units adjacent to/infiltrating the left dome of the diaphragm, hyperplasia of the right adrenal gland, and numerous sclerotic bone lesions concerning for metastases ( Figure 1 ). ACTH overstimulation. 18FDG-PET-CT also showed multifocal metabolically active sclerotic bone lesions in the spine, ribs, clavicles, scapules, sternum, pelvis, femurs, and humerus. A SUVmax 2.1 area (not correlated with CT imaging) was also found in the anterior mediastinum, which has been considered primarily as a residual thymus with physiological FDG uptake ( Figure 1 ).
case_images: Eight-week follow-up 18F-FDG-PET-CT presenting metabolically active lesion in the superior anterior mediastinum in the thymus location (A1, A2). Axial CT (B) and MRI (C) scans of the chest presenting mediastinal mass corresponding to the invasive thymic malignancy.
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case_images: PMC11211248_01_fendo-15-1399930-g002.jpg
case_images: f2
case_images: A follow-up 18F-FDG-PET-CT performed after 8 weeks revealed a metabolically active mass (SUVmax, 9.3) in the superior anterior mediastinum in the thymus location ( Figure 2A ). CT ( Figure 2B ) and the subsequently performed MRI ( Figure 2C ) of the chest confirmed mediastinal mass measuring 42 mm x 33 mm, adjacent to the trachea and superior vena cava, encircling the ascending aorta and aortic arch, most likely corresponding to the invasive thymic malignancy.
case_images: Large-cell neuroendocrine carcinoma of the thymus with atypical carcinoid morphology, pathological diagnosis. (A) Microscopic image of the primary tumor, HE staining. (B) Weak positive IHC staining for ACTH. (C) Microscopic image of the brain metastasis, HE staining. (D) Weak positive IHC staining for ACTH of the brain metastasis. (E) Electron microscopic image of cancer cells; the material was taken from a paraffin block, which resulted in a poorly preserved ultrastructure. Visible neuroendocrine granules concentrated around the cell nucleus (x17,500). (F) Ultrastructural image of the neuroendocrine granules with a diameter of (x24,500).
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case_images: PMC11211248_01_fendo-15-1399930-g003.jpg
case_images: f3
case_images: On IHC, the tumor stained positive for CgA, synaptophysin, and CD56, and weakly for ACTH; the Ki-67 index was 40%, p53 expression was 70% ( Figure 3 ).