Expression of Thymidine Phosphorylase in Lymph Nodes Involved with Mycosis Fungoides and Sézary Syndrome

Abstract EN

Thymidine phosphorylase may be overexpressed in both neoplastic cells and tumor stromal cells in a variety of malignancies.

Our study explores thymidine phosphorylase expression in lymph nodes (LNs) from patients with mycosis fungoides (MF) or Sézary syndrome (SS).

In MF/SS, the LNs may have a pathologic diagnosis of either dermatopathic lymphadenopathy (LN-DL) or involvement by MF/SS (LN-MF).

We performed immunohistochemical staining on MF/SS lymph nodes using antibodies to thymidine phosphorylase, CD68, CD21, CD3, and CD4.

In both LN-DL and benign nodes, thymidine phosphorylase staining was noted only in macrophages, dendritic cells, and endothelial cells.

In LN-MF, thymidine phosphorylase expression was also noted in subsets of intermediate to large neoplastic T cells.

Concurrent CD68, CD21, CD3, and CD4 staining supported the above observations.

Similar results were noted in the skin and in LN-MF with large cell transformation.

Other T-cell lymphomas were also examined (total 7 cases); only enteropathy-type T-cell lymphoma (1 case) showed TP positivity in neoplastic T lymphocytes.

We demonstrated that thymidine phosphorylase staining is present in neoplastic T cells in mycosis fungoides.

The exact mechanism needs further investigation.