The Spread of Malignant Lymphomas in Children
Authors: Bonadonna Gianni , Fossati-Bellani Franca 
Published: April 2018

The preferential sites of involvement and the mode of spread of malignant lymphomas have been evaluated in 71 consecutive untreated children up to and including the age of 15 years (33 with Hodgkin's disease, 19 with lymphosarcoma and 19 with reticulum cell sarcoma). In all cases the diagnosis was defined by pathological examination. Lower-extremity lymphography (3–5 ml of Lipiodol Fluid per foot) was carried out only in 17 patients (10 with Hodgkin's disease and 7 with lymphoreticular sarcomas) without untoward reactions or pulmonary complications. Patients were staged according to the international four stage clinical classification proposed at Rye in 1965. Hodgkin's disease was confined to lymph nodes and spleen in practically all patients (97.5%), while in comparison lymphoreticular sarcomas revealed an appreciable involvement of Waldeyer's ring (6.5%) and a considerable extension to extranodal sites (18%) with frequent invasion of adbomen and bone marrow. Mediastinal nodes were definitely more involved in Hodgkin's disease (18.5%) than in lymphoreticular sarcomas (5.5%), while the opposite occurred for extensions below the diaphragm (inguinal, retroperitoneal and mesenteric nodes). The mode of spread has been studied by counting the number of untreated patients (only with primary involvement of lymph nodes and Waldeyer's ring) with contiguous and non contiguous adenopathies, as well as the next sites of involvement after localized radiation therapy. The majority of children with Hodgkin's disease showed adenopathies distributed throughout contiguous areas (15/18 cases). This occurred also in those with lymphoreticular sarcomas (5/8 cases) although in 4/5 patients the disease had its primary onset in Waldeyer's ring where, as in adults, cervical adenopathies are often present. A total of 14 children with Hodgkin's disease developed a recurrence after different lengths of time. This occurred in 10 patients in lymph node-bearing areas clinically uninvolved at the time of initial work up, but adjacent to those treated with local radiation therapy. The lymphoreticular sarcomas, on the contrary, showed a tendency to spread earlier to viscera and bones. The analysis of our pediatric lymphomas shows that the spread of Hodgkin's disease in children is similar to that observed in adults, i.e. with an initially slow and orderly lymphatic progression in the large majority of patients. Lymphoreticular sarcomas on the contrary, with the possible exception of those arising in Waldeyer's ring, were very often a generalized process (Stage IV) at the time of presentation with frequent invasion of bone marrow and abdominal cavity. These observations could be probably explained in part by the fact that lymphoreticular sarcomas arise in the gastrointestinal tract or in lymph nodes below the diaphragm (retroperitoneal, mesenteric) in a much higher percentage than usually seen on routine work up. Therefore through the thoracic duct, and without involvement of mediastinum, malignant cells reach the blood stream earlier. The orderly lymphatic spread in most patients with Hodgkin's disease and the predominant dissemination through the blood stream in lymphoreticular sarcomas could explain the difference in prognosis. On the basis of the mode of spread prophylactic irradiation to adjacent clinically uninvolved lymphoid regions is therefore indicated in patients with Hodgkin's disease and only in lymphoreticular sarcomas with primary involvement of Waldeyer's ring.