Recurrences in nodal T-cell lymphoma - Changes in histologic appearance and immunophenotype over the course of disease

We examined the patterns of relapse or persistence in 37 cases of nodal per ipheral T-cell lymphoma (PTCL) to address the morphologic and immunophenoty pic findings. Relapses were documented in lymph node (25 cases) and/or a va riety of extranodal sites at a mean of 21 months after presentation; severa l cases recurred as late as 13 years. persistent bone marrow involvement wa s a feature of angioimmunoblastic lymphoma (AIL) and histiocyte-rich and sm all-cell tumors. Relapses in anaplastic tumors often involved unusual extra nodal sites. The majority of relapsed PTCLs retained a similar histologic a ppearance, pattern of nodal involvement and immunophenotype. Histologic pro gression, as assessed by increased numbers of large cells, was seen in 3 ca ses of AIL, in I case with an initial small cell morphologic appearance, an d in 2 cases of PTCL with an initial mixed small and large cell appearance Immunostains for T-cell activation markers showed increased immunoreactive cells in 5 of the 6 cases, whereas increased numbers of p53-positive tumor cells were noted in 3 of the 6 cases. The discrete large cell transformatio n occasionally seen in B-cell lymphoma and extranodal T-cell lymphoma was n ot observed in these cases.