The Abscopal Effect in Malignant Lymphoma and Its Relationship to Lymphocyte Circulation

THE ABSCOPAL effect may be defined as a significant tumor tissue response to irradiation in tissues definitively separate from the area treated. The response must be measurable: i.e., visible, radiographic, or palpable decrease in size of lymph nodes or other masses, or disappearance of effusions or of ascites. In addition, the distance separating the responding tissues and the portal(s) of irradiation must be great enough to rule out any possible effect of scattered radiation. Abscopal reactions are most commonly seen in the chronic leukemias, wherein irradiation of an enlarged spleen and/or liver will induce a generalized remission, with return of the bone marrow, white blood count, and peripheral smear to normal ranges. In terms of other malignant tumors, this poorly understood abscopal phenomenon is often alluded to in standard textbooks (4, 7), but specific case reports are lacking. A review of the recent literature failed to reveal a single report of an abscopal reaction in a condition other than leukemia. Case Report In this 52-year-old white male, previously in excellent health, there developed a pleuritic type of right anterior chest pain and intermittent crampy and dull midabdorninal pains three weeks prior to hospitalization. A review of systems was entirely negative otherwise. On physical examination, all vital signs were within normal limits. Multiple firm, nontender, moderately enlarged lymph nodes were palpable in the cervical, axillary, inguinal, and femoral regions, bilaterally. Breath sounds were decreased at both lung bases. Cardiac examination was entirely normal. The liver and spleen were palpable. There was no evidence of ascites. Laboratory findings were as follows: hemoglobin, 9.4 mg per 100 ml; hematocrit, 28 per cent; “a mild microcytic hypochromic type” of anemia; white blood count, 5,800 WBC/mm. 3, with a differential showing 30 per cent lymphocytes, 12 per cent monocytes, 1 per cent eosinophils, 52 per cent polymorphonudears, and 5 per cent bands; platelet and reticulocyte counts, urinalysis, and liver chemistries, all within normal limits; uric acid 10.3 mg per 100 ml, and BUN 67 mg per 100 ml. The electrocardiogram was interpreted as completely normal. Initial chest films (Fig. 1) demonstrated bilateral pleural effusions; there was no evidence of cardiomegaly, pulmonary vascular congestion, or pulmonary infiltration. A dripinfusion urogram showed bilateral hydronephrosis with dilatation and displacement of both ureters by a retroperitoneal mass. Biopsy of a right axillary lymph node disclosed “malignant lymphoma of the giant follicle type, (with) invasion of lymph node capsule and surrounding tissues seen in several areas.” A lymphangiogram (Fig. 2) demonstrated unequivocal lymphomatous involvement of multiple pelvic and paraaortic lymph nodes.