Immunophenotypic features of PI-ENKTCL.

<p>The neoplastic cells were positive for CD3 (A), CD56 (B) and TIA-1 (C). Positivity for CD30 (D) was seen in some larger atypical cells.</p

A representative case of primary intestinal CD4+ ENKTCL involving the ileum.

<p>(A) The neoplastic cells were predominantly small to medium-sized ones with slightly irregular nuclei. Tumor cells were diffusely positive for (B) CD56 and (C) CD4. (D) In situ hybridization for EBER demonstrated positive signals.</p

Histological features of PI-ENKTCL.

<p>(A) A low power view of the H&E stained section showed the overlying mucosa was partially effaced and the neoplastic cells extensively infiltrated the muscular wall. (B) A blood vessel with invasion by the neoplastic cells was shown. (C) A high power view demonstrated that the tumor was composed of a mixture of small, medium and large atypical lymphoid cells, with some hallmark cells identified. (D) Numerous eosinophils and plasma cells were intermingled with the tumor cells.</p

The clinicopathological features of primary intestinal CD4+ ENKTCL.

<p>The clinicopathological features of primary intestinal CD4+ ENKTCL.</p

Kaplan-Meier survival curves of patients with PI-ENKTCL according to CD4 expression.

<p>Patients with a CD4-positive tumor had a slightly better OS compared with those with CD4-negative ones, although the difference was not statistically significant (<i>p</i> = 0.192).</p