A suspected gastric cancer recurrence that proved to be a desmoid tumor

What happened, in summary

A 68-year-old man was diagnosed in 2019 after endoscopy found a broad depressed lesion in the upper stomach. Biopsy showed poorly differentiated adenocarcinoma. He underwent robot-assisted laparoscopic distal gastrectomy with lymph-node dissection in November 2019. Pathology showed a Stage I tumor confined to the stomach lining, with no lymph-node involvement and clear margins. He recovered well and did not receive adjuvant chemotherapy.

Two years later, follow-up CT found a 38 x 36 mm soft-tissue mass beside the remaining stomach. PET imaging showed moderate activity, raising concern for recurrent gastric cancer or lymph-node metastasis, but no disease was seen elsewhere. Endoscopic ultrasound-guided biopsy found spindle-shaped cells but could not establish a diagnosis.

Because malignancy could not be ruled out, he underwent extensive surgery to remove the residual stomach together with the mass and involved adjacent tissue. Final pathology showed a desmoid tumor, not recurrent gastric cancer. He developed a postoperative pancreatic fistula that resolved with drainage and was discharged on day 16. Six months later there had been no recurrence of the removed mass, and the suspected gastric cancer recurrence had been disproved.