[Non-hodgkin's lymphomas of extranodal localization. Strategies for imaging diagnosis]

To evaluate the diagnostic workup proposed by the UICC (International Union against Cancer) Flow charts for diagnosis and staging of lymphomas in developed and developing countries (1998).

Our series consists of 134 patients with early non-Hodgkin's lymphoma (NHL). The patients, 75 men (56%) and 59 women (44%), ranging in age 14-80 years (mean: 56.8), were examined with chest radiography and thoracoabdominal CT. Abdominal US was used only in the follow-up of low-grade NHL. The patients were classified according to the Working Formulation criteria (1981) and staged as proposed by the Ann Arbor Conference guidelines (1971).

At diagnosis, 5 patients (3.7%) were in stage I, 32 (23.8%) in stage II, 46 (34%) in stage III and 51 (38%) in stage IV. Extranodal involvement was seen in 59 patients (44%), which was present at disease onset in 49 of them (80%) and developed later on in 10 (20%). Gastrointestinal tract and respiratory system were the most frequent sites of extranodal involvement (15 cases, 25%), followed by liver (12%), genitourinary system (including the ovary), adrenal glands, the craniocervical region, muscles and finally the breast. The parotid gland, thyroid and bone were involved in one case only each.

In agreement with previous literature reports, our study confirms that the best technique currently available for diagnosis, staging and follow-up of malignant lymphoma is chest-abdomen CT. Indeed, even though extranodal involvement exhibits extremely variable patterns, there are some typical findings at CT, such as homogenous structural hypodensity, low contrast enhancement, frequent plurivisceral involvement and/or local lymph node involvement. Our study followed the 1998 UICC guidelines for cancer diagnosis and staging in developed countries, based on the histology of lymph node biopsy material and on imaging techniques such as CT, MRI and PET. As for developing countries, lymph node biopsy is the most easily available, and thus preferred, examination, while imaging diagnosis features chest radiography and abdominal US.