Parietal cell/oncocytic gastric carcinoma: systematic review and first-time assessment of HER2 status in two new cases.
INTRODUCTION
Parietal cell/oncocytic gastric carcinomas are very rare and various aspects of this group remain unclear. The human epithelial growth factor receptor 2 (HER2) status of these tumours is largely unknown.


METHODS
We performed a systematic electronic search of the literature and clinicopathological presentation of two cases including first-time complete assessment of HER2 status. Thirty-two patients with a mean age of 64.3 years, 87.5% of whom were male, were included in this review.


FINDINGS
Half of the cases were recorded in Asia. Median follow-up was 24 months. There was no predominant site of development, while underlying histological abnormalities were present in 25%. At initial presentation, lymph node involvement was evident in 46.6% while distant metastatic disease was present in 9.3%. Presentation at stage I occurred in 55.6%. Potentially curative surgical/interventional treatment was intended in 90.6%. Recurrence occurred in 6.6%, while death was recorded in 19.2%, with cancer-related deaths reaching 11.5%. The one- and three-year survival rates were 84.2% and 79%, respectively. Our two cases displayed negative HER2 expression.


CONCLUSIONS
This systematic review demonstrates that this group of malignancies is very rare but possibly underdiagnosed. The disease commonly presents at early stage, mainly affecting middle-aged men. The prognosis is generally favourable even in cases of advanced disease. The HER2 expression and its correlation with the outcomes need to be further explored.
['Mavroeidis|V K|VK|', 'Gkegkes|I D|ID|', 'Saffioti|F|F|', 'Kandilaris|K|K|', 'Alexiou|K|K|', 'Horti|M|M|', 'Economou|N|N|', 'Demonakou|M|M|']
D000369:Aged, 80 and over D014408:Biomarkers, Tumor D002277:Carcinoma D017024:Chemotherapy, Adjuvant D018572:Disease-Free Survival D005260:Female D005743:Gastrectomy D006115:Greece D006801:Humans D008207:Lymphatic Metastasis D008297:Male D008875:Middle Aged D009364:Neoplasm Recurrence, Local D010295:Parietal Cells, Gastric D018719:Receptor, ErbB-2 D012737:Sex Factors D013274:Stomach Neoplasms D015996:Survival Rate
Parietal cell Oncocytic HER2 Gastric cancer Mitochondrion-rich