Clear cell carcinoid tumor of stomach. A variant mimicking gastric xanthelasma

We report a rare case of gastric carcinoid composed entirely of clear cells with foamy cytoplasm. The patient was a 75-year-old Hispanic woman with atrophic fundic (oxyntic) gland gastritis leading to hypochlorhydria, secondary hypergastrinemia, endocrine cell hyperplasia, and multiple gastric carcinoids. Grossly, the lesion was yellow and distinct from other carcinoids in the gastric mucosa, mimicking gastric xanthelasma. Histologically, the tumor consisted of uniform clusters of polygonal cells with foamy cytoplasm. The formation of cell packets and abundant vascular stroma provided clues to its neuroendocrine nature. This was confirmed by immunoreactivity for chromogranin A and the demonstration of dense core granules ultrastructurally.