Sarcoma arising from interdigitating reticulum cells: report of a case, studied with light and electron microscopy,...

The morphological, enzyme- and immunohistochemical features of a sarcoma arising from interdigitating reticulum cells (IDRC) are presented. These cells are normal constituents of the T-dependent region of lymphoid organs, and their function is largely unresolved. The immunohistochemical findings in the present case indicate that neoplastic IDRC are morphologically and phenotypically similar to normal IDRC in lymphoid organs. Functionally however, neoplastic IDRC more closely resemble IDRC in the fetal lymph node and in the thymus, where they are thought to play a role in the final differentiation of immature thymocytes into mature peripheral T-lymphocytes.