Primary Extranodal Follicular Lymphoma: Clinicobiological Features and Outcome.

Follicular lymphoma (FL) is typically a nodal disease. Primary extranodal FLs, that represent less than 10% of the cases, might have differentiated clinicobiological features. The aim of the present study was to analyze the main clinicobiological characteristics, response to therapy and outcome of a series of patients with FL primarily extranodal in origin, and compare them with nodal FLs. Twenty two patients (12M/10F; median age, 59 years) with FL with primary origin in extranodal location diagnosed in a single institution during a 24-year period, with primary origin in extranodal location were the subject of the study. The control group was constituted by 212 patients with nodal FL diagnosed during the same period of time. Main clinicobiological features were recorded and analyzed. The sites of the primary disease were: skin, 5 cases; Waldeyer’s ring, 4; GI tract, 3; bone marrow, CNS and parotid (two cases each); and pancreas, thyroid, kidney and orbit (one case each). Main histological and clinical features are listed in the table. Treatment was given without considering the nodal or extranodal origin of the disease and consisted of: monotherapy with alkylating agents (38 cases), polychemotherapy (149), and fludarabine alone or with other drugs (14) and others, including surgery and observation (33). CR rate was higher in extranodal than in nodal FL (82% vs. 53%, respectively; p=0.02), but no differences were found in overall survival. FLIPI score was the most significant variable predicting overall survival in the global series as well as in either in nodal or extranodal FL.

In conclusion, extranodal FL had some peculiar clinicobiological features with respect to nodal cases. Regarding the outcome, although patients with extranodal FL showed a higher CR rate, the overall survival was similar in both groups.