Indolent T-cell lymphoma of the gastrointestinal tract coexisting with gastric signet-ring cell carcinoma: A case report and review of literature.

BACKGROUND: Indolent T-cell lymphoma of the gastrointestinal tract (iTCL-GI) is a rare mature T-cell lymphoma that has been formally recognized as a distinct entity in the 5th Edition World Health Organization Classification of Tumours of Haematolymphoid Tumours. However, the coexistence of iTCL-GI with epithelial malignancies is rare in clinical practice. This study reports a case of iTCL-GI with gastric signet-ring cell carcinoma (SRCC). We aim to increase diagnostic awareness among clinicians and pathologists regarding multiple primary tumors.

CASE SUMMARY: A 65-year-old female presented with a 5-month history of lower abdominal pain, bloating, and vomiting. An abdominal computed tomography scan revealed irregular thickening of the gastric wall. Endoscopy revealed diffuse mucosal edema and rigid mucosa along the lesser curvature of the gastric body. There was a 1.5 cm mucosal protrusion on the greater curvature. Biopsy revealed that the lamina propria was expanded by a dense, nondestructive infiltrate of small lymphocytes in the greater curvature, which were characterized by a CD3+/CD8+/TIA-1+ immunophenotype with a low Ki-67 index. Clonal T-cell receptor rearrangement was detected, but the Epstein-Barr virus encoded RNA's was negative. Lesions on the lesser curvature of the gastric body were confirmed to be SRCCs. After three months of follow-up, the patient completed four cycles of chemotherapy targeting the SRCC. While her abdominal pain improved, she experienced a weight loss of 5 kg.

CONCLUSION: Clinicians and pathologists must integrate assessment of these rare cases to prevent misdiagnosis and guide clinical practice.