Early gastric cancer presenting as a typical submucosal tumor cured by endoscopic submucosal dissection: A case report

Abstract

BACKGROUND

Submucosal tumor (SMT)-like gastric cancer is rare, and almost all cases undergo curative surgical treatment because the submucosal layer is usually deeply invaded by tumor cells or because histopathologic types of SMT-like gastric cancer are undifferentiated or poorly differentiated. No report has been issued on an SMT-like gastric cancer cured by endoscopic resection alone or on changes in the endoscopic features of this type of tumor over several years.

CASE SUMMARY

We describe an exceptional case of a 53-year-old male with a 1.5 cm-sized SMT-like lesion covered by normal-appearing mucosa discovered by esophagogastroduodenoscopy (EGD) at the gastric antrum. Endoscopic ultrasound (EUS) visualized a homogeneous, well-circumscribed hypoechogenic lesion arising from the second sonographic layer with associated subtle obliteration of the third sonographic layer. Initial endoscopic biopsy was negative for neoplasm. The patient refused to undergo an invasive procedure and was subsequently lost to follow-up. Three years after initial detection, EGD revealed the lesion had become markedly erythematous, and at 4 years after initial EGD it had increased in size to 1.8 cm and developed a central ulcer and a heterogeneous EUS echo. Finally, endoscopic submucosal dissection (ESD) was performed, and histopathologic examination revealed a moderately differentiated adenocarcinoma had minutely invaded the submucosal layer (invasion depth 169 μm) but without lymphovascular invasion and with negative resection margins. Fortunately, no additional surgical treatment was required. He has been followed for 4 years after ESD without any evidence of local or distant recurrence.

CONCLUSION

This report describes an extremely rare case of early gastric cancer presenting as SMT that was cured by ESD after a treatment delay of 4 years and the endoscopic changes that occurred during this period. The report highlights the importance of considering the possibility of gastric cancer when SMT is encountered in clinical practice.

Keywords: Subepithelial lesion, Submucosal tumor, Early gastric cancer, Adenocarcinoma, Endoscopic mucosal dissection, Case report

Core Tip: We experienced an exceptionally rare case of early gastric cancer presenting as submucosal tumor (SMT) that was successfully treated by endoscopic submucosal dissection (ESD) alone, although the procedure was performed four years after first detection due to patient refusal and follow-up loss. The present case cautions that SMT-like gastric cancer should be included in the differential diagnosis when a hypoechogenic mass is detected in the 2^nd or 3^rd layer by endoscopic ultrasound, regardless of size and the absence of findings suggesting malignancy. When diagnosis is uncertain, invasive techniques such as diagnostic endoscopic mucosal resection or ESD, which can potentially be used for therapeutic purposes, should be considered and close follow-up is recommended.