Paediatric T-cell lymphoma of the appendix: a case report

Abstract

A 7-year-old boy with no history of malnutrition or diarrhoea complained of acute abdominal pain, was diagnosed with acute appendicitis, and underwent appendectomy. Histologically, a diffuse infiltrate of large atypical lymphoid cells was found in the entire appendiceal wall. Immunohistochemical examination revealed that the tumour cells expressed T-cell receptor (TCR)-βF1, CD3, CD4, CD25, cytotoxic-related protein TIA1 and granzyme-B, but were negative for CD8, Foxp3, CD20, CD30 and CD56. Polymerase chain reaction (PCR) revealed clonal bands of TCR-γ gene products in the tumour tissue. No anti-cytomegalovirus antibody-positive cells were detected. In situ hybridization revealed no nuclear signals of Epstein-Barr virus (EBV)-encoded RNA. Helicobacter pylori infection was detected in tumour tissue by anti-East Asian cytotoxin-associated gene (Cag) A antibody and PCR using its specific primers. The patient received chemotherapy and has remained in remission for 2 years. To the best of our knowledge, only two cases of appendiceal T-cell non-Hodgkin lymphoma (NHL) have been reported, both in elderly patients. We believe that this is the first reported case of childhood CD4- and TIA1-positive cytotoxic T (Th1)-cell NHL in the appendix or gastrointestinal tract. Helicobacter pylori infection might be an initiator of atypical cytotoxic T-cell proliferation.

Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1302380563830412.

Figure 1

Histological features of the appendix. (A) Atypical lymphoid cells and preserved lymph follicle are in submucosal layer (H&E stain, ×100). (B) Intraepithelial lymphocytes are not increased, and abnormal tumour cell invasion is not prominent in the mucosal layer (H&E stain, ×200). Large atypical lymphocytes with small distinct nuclei diffusely infiltrate the (C) submucosal layer and (D) eroded lesion. Many reactive histiocytes are seen, mainly in (C) (H&E stain, ×400).

Figure 2

Immunohistological findings in the appendix. (A) CD3-positive tumour cells distributed mainly in the submucosal and muscle layers (×100). Infiltrating atypical large lymphoid cells are positive for (B) CD4 and (C) TIA1 (×200). TIA1-positive lymphoma cells invade the muscle layer. (D) Rod-like substances in the foveolar pit are positive for anti-East Asian type H. pylori CagA antibody (×400).

Figure 3

Detection of TCR-Vγ1f to -Jγ1.1/2.1 gene products. C1: nodal adult T-cell leukaemia/lymphoma (positive control); C2: non-neoplastic intestinal specimen (negative control); Pat.: patient sample. The 230 bp clonal band (TCR-Vγ to Jγ) is identified in lane C1 and in the patient sample.

Figure 4

Detection of the CagA gene of the East Asian type H. pylori. The CagA gene (222 bp clonal bands) detected in DNA extracted from tissue specimens using primer set CAGJF/CAGTR. C1 and C2: H. pylori-positive gastritis cases. C3: H. pylori-negative gastritis case. Pat.: patient sample.