Parietal cell/oncocytic gastric carcinoma: systematic review and first-time assessment of HER2 status in two new cases

Abstract

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.

Parietal cell/oncocytic/mitochondrion-rich gastric carcinoma: a need for clarity in terminology

“…2 PCGCs are primary adenocarcinomas of the stomach that display a glandular or solid pattern of growth occasionally mimicking lymphomas or mesenchymal tumours of smooth muscle origin. 2 Neoplastic cells are usually polygonal with round nuclei and oncocytic features with abundant eosinophilic, granular cytoplasm reactive with phosphotungstic acid haematoxylin (PTAH) and Luxol fast blue. 2e4 Commonly, immunohistochemical stains for antimitochondrial antibodies are strongly positive.…”

“…2e4 Commonly, immunohistochemical stains for antimitochondrial antibodies are strongly positive. 2,3 The ultrastructural features of tumour cells correspond to an 'oncocytic cytoplasm' with abundant mitochondria, tubulovesicles, intercellular lumina filled with undulating microvilli and intracellular canaliculi. 2e5 In 2002 Takubo et al presented 10 cases of gastric adenocarcinoma with morphological features similar to those of parietal cell carcinoma, however immunohistochemical staining of the tumours with four different antiparietal cell antibodies (anti-H þ -K þ -adenosine triphoshatase antibodies) was negative in all cases.…”

“…8 Following the publication by Takubo in 2002, the terms 'parietal cell' and 'oncocytic gastric carcinoma' have been alternately used in the literature, however it still remains unclear whether the terms represent different entities. 2 Additionally, it has been suggested recently that there may be a partial overlap of such neoplasms with 'gastric adenocarcinoma of the fundic gland type with predominant parietal cell differentiation'. 8 Both tumours reported so far either as parietal cell or oncocytic carcinomas appear to have received similar forms of treatment and have a similar favourable prognosis.…”

“…8 Both tumours reported so far either as parietal cell or oncocytic carcinomas appear to have received similar forms of treatment and have a similar favourable prognosis. 2,6 Given the extensive morphological similarities of these tumours, if it were to be accepted that the different names represent different entities or subtypes of the same entity, the biological significance of this distinction should be clarified, and the potential implications for treatment and prognosis.…”

“…The rarity of primary gastric adenocarcinomas with an oncocytic morphology implies that more cases must be studied before the biological significance of novel efforts in the field of histological classification can be ascertained. 2 In 2010, Caruso et al reported on nine cases of gastric adenocarcinoma with eosinophilic cytoplasm predominantly in the supranuclear portion, for which they suggested the term 'mitochondrion-rich carcinomas' (MRC). They chose this term as the tumour appeared to be the gastric counterpart of mitochondrion-rich follicular carcinoma of the thyroid.…”