Lymphomatoid granulomatosis and angiocentric lymphoma: A spectrum of post-thymic T-cell proliferations

Twenty-three patients with AILs, including angiocentric lymphoma, were evaluated clinically and pathologically. Pathologic subclassification performed without knowledge of the clinical outcome divided the cases into three histologic grades. Grade I lesions (nine classes) had little or no cytologic atypia, whereas moderate cytologic atypia with a polymorphous inflammatory background was found in the six cases classified as grade II. Eight cases were classified as grade III, equivalent to angiocentric lymphoma, further subclassified in the working formulation as diffuse, mixed small, and large cell (6), diffuse, large cell (1), and diffuse, large cell immunoblastic (1). Progression to malignant lymphoma after initial immunosuppressive therapy with cyclophosphamide and prednisone occurred in three of nine patients with grade I lesions and four of six patients with grade II. The supervening lymphomas were usually refractory to subsequent aggresive chemotherapy, with only one patient achieving a CR. In contrast, seven of eight patients with grade III lesions achieved a CR with aggressive combination chemotherapy, two of whom also received supplemental radiation therapy. Immunophenotypic studies of lesions from six patients demonstrated a mature T-cell phenotype with a predominance of helper T cells. Abnormalities of antigenic phenotype were demonstrated in only one case, classified as grade III. That tumor was found to be clonal on the basis of a rearranged T-cell antigen receptor beta chain detected by Southern blot analysis. These studies support the concept that the angiocentric immunoproliferative lesions represent a spectrum of post-thymic T-cell proliferations. The single most important prognostic indicator for ultimate survival is achievement of an initial CR. Aggressive combination chemotherapy may be necessary to achieve CR in patients with grades II and III lesions, and consolidative radiation therapy may be of value. Patients treated initially with conservative chemotherapy may be compromised in their ability to achieve a CR if they progress to a more high-grade lesion.