Primary non-Hodgkin's lymphoma of the thyroid gland are infrequent tumors.
They almost exclusively derive from B cells of mucosa-associated lymphatic
tissue and only a very small minority of them are T cell lymphomas. CD30 mo
lecule, other than in Hodgkin's and Reed-Sternberg cells, is strictly assoc
iated with anaplastic large cell lymphoma and ALK lymphomas, the latter bei
ng identified by the monoclonal antibody ALK1. We report a case of CD30-pos
itive non-anaplastic (ALK1-negative) peripheral T cell lymphoma of the thyr
oid gland and speculate on aspects concerning diagnosis and the morphologic
and immunohistochemical findings. (C)1999, Ferrata Storti Foundation.