Pure Glycogen-Rich Clear Cell Adenocarcinoma of the Stomach

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.

Clear cell carcinoma of the stomach: a rare tumor variant imparting poor prognosis

INTRODUCTION

Clear cell gastric cancer (CCGC) represents an extremely rare variant of adenocarcinoma of the stomach. It can be mistaken for a clear cell metastatic lesion arising from other anatomic parts, especially renal cell carcinoma.

PATIENTS AND METHODS

We describe the case of a 66-year-old woman who was operated for a pyloric adenocarcinoma which resulted to be a CCGC at definitive histology. Moreover, we offer a systematic review of the current pertinent literature on CCGC.

RESULTS

Our case represents the 160th example of CCGC. Clear cell aspect is due to the intracytoplasmic accumulation of glycogen in most cases, followed by mucin, lipid or water; the reason of the underlying biochemical process is still unclear. Paralleling other epithelial clear cell malignancies (as ovarian, bladder, urothelial or pancreatic cancers), also CCGC shows a more aggressive clinical behavior over conventional neoplastic counterparts.

CONCLUSIONS

Differently from clear cell carcinomas involving other organs, CCGC has been rarely investigated by the literature. Since, compared to non clear cell cancers, this particular phenotype of gastric cancer appears to be associated with poorer prognosis, further studies are needed in order to corroborate its real adverse prognostic significance and standardize the correct management and treatment.