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Abstract
Magnetic resonance imaging (MRI) of the head on March 4 showed abnormal signals in the bilateral hippocampus of temporal lobes, medial frontal gyrus, hypothalamus, basal ganglia region, posterior limb of the internal capsule, and corpus callosum on T2-weighted [Figure 1]a and fluid attenuated inversion recovery imaging. Magnetic resonance spectroscopy showed an increased lactic acid peak and a slightly low NAA/creatine value. The patient had hyponatremia without edema. Because serum osmolality was low and urine osmolality was greater than serum osmolality, the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was diagnosed. Multiple solid nodules were observed on the left side of the carotid artery, and the largest was 3.7 cm × 2.2 cm, with a smooth margin, regular shape, uneven echo, and high blood flow signal. A positron-emission tomography/CT (PET/CT) scan on March 11 showed a hypermetabolic (remarkable F-18 fluorodeoxyglucose uptake) soft tissue mass image in the right posterior wall of the hyopharynx (2.5 cm × 2.6 cm) involving the glottis. Simultaneously, a whole-body PET/CT examination ruled out other related carcinomas, such as small cell lung cancer and testicular tumor. Vesicular nuclei were commonly seen with a distinct nucleolus and mitotic figures [Figure 1]b. According to immunohistochemical analysis, the tumor...