Gastric Adenocarcinoma With Unusual Clear Tubulopapillary Morphology: A Case Report

Gastric clear cell adenocarcinoma is an extremely rare variant of papillary adenocarcinoma of the stomach. It is associated with a poor prognosis due to its frequent lymphovascular invasion and also its higher risk of recurrence. It is characterized morphologically by a clear appearance of tumor cells, which can be easily confused with a metastasis of a clear cell carcinoma, particularly of renal origin. Very few cases have been previously reported in the literature, which makes it a very poorly known variant. Here, we report the case of a 64-year-old patient who presented with a polypoid lesion in the pylorus, revealed by epigastric pain and chronic vomiting. Histological analysis showed a gastric clear cell adenocarcinoma with a tubulopapillary architecture. Immunohistochemical examination excluded a metastasis of renal origin. Through this case report, we highlight the importance of recognizing such an uncommon and unusual variant of gastric adenocarcinoma, to prevent any potential misdiagnosis.