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

Table 1 T-cell receptor gene rearrangement results

Mastermix	TCRB tube-A	TCRB tube-B	TCRB tube-C	TCRG tube-A	TCRG tube-B	TCRD
Target	νβ-Јβ	νβ-Јβ	Dβ-Јβ	νγ1-8, νγ10 + Јγ	νγ9, νγ11 + Јγ	νδ + Dδ + Јδ
Valid detection range (bp)	240-285	240-285	170-210, 285-325	145-255	80-140, 160-220	120-280
Highest peak/third highest peak ratio	> 3-5	> 3-5	> 3-5	> 5-7	> 5-7	> 5-7
Result	+	+	-	-	-	-

If any reaction tube (excluding controls) exhibited one or two discrete amplification peaks within the valid detection range and if the peak intensity met the criteria specified in Table 1 (maximum peak height > 1000), the sample was considered positive for T-cell clonality. TCR: T-cell receptor.

Table 2 Comparison of different types of T-cell lymphomas involving the gastrointestinal tract

Feature	Indolent T-cell lymphoma of the gastrointestinal tract	Enteropathy-associated T-cell lymphoma	Monomorphic epitheliotropic intestinal T-cell lymphoma
Epidemiology	Often chronic and relapsing, but with a favorable long-term prognosis. The etiology is unknown	More common in Europe and United States. Genetic background of CD, refractory celiac disease	More common in Asia. There is no association with celiac disease (CD)
Major clinical presentation	Abdominal symptoms (such as chronic diarrhea, pain, vomiting dyspepsia)	Abdominal symptoms (such as pain, diarrhea) and weight loss; common bowel perforation or obstruction	Abdominal symptoms (such as pain, bleeding) and weight loss; common bowel perforation or obstruction
Commonest localization in the gastrointestinal tract	Small bowel or colon	Small intestine	Small intestine
Lesional involvement of gastrointestinal tract	Superficial (mucosal or submucosal)	Circumferentially oriented ulcers or ulcerated nodules	Ulcerated mass
Histopathology	Small lymphoid cells with minimal nuclear atypia. The lamina propria is usually expanded. Intraepithelial lymphocytes are not increased	Medium-sized to large lymphoid cells. A variable inflammatory background. Angioinvasion and angiodestruction	Small to medium-sized cells. Lacking necrosis and an inflammatory background. Epitheliotropism is common
Immunophenotype	CD3+, CD8+ with TIA-1+ and/or CD4+, Ki 67 < 10%	CD3+, CD7+, CD103+; positive for TIA1, granzyme B, and perforin	CD2+, CD3+, CD7+, CD8+, CD56+, CD5-, CD4-, TIA-1+
T-cell receptor expression	TCRαβ+	Usually, negative	Usually, TCRγδ+ or TCRαβ+
Molecular genetics	JAK2: STAT3 fusion; mutations of JAK/STAT pathway genes and epigenetic modifier genes	Gains of 9q34; loss of 16q12; mutations of JAK/STAT pathway genes (commonly JAK1 and STAT3)	Gains of 9q34; loss of 16q12; mutations of JAK/STAT pathway genes (commonly JAK3, STAT5B) and SET domain-containing 2
Clinical course	Indolent, often chronic persistent or relapsing	Aggressive	Aggressive

CD: Crohn's disease; JAK: Janus kinase; STAT: Signal transducer and activator of transcription; TCR: T-cell receptor.