Twenty-three patients, 9 with immunoblastic lymphadenopathy and 14 with atypical immunoproliferative disorders (A1PD), were studied in order to determine their clinical, radiographic, and pathologic features. Diffuse lymphadenopathy was present in all patients. Patients with immunoblastic lymphadenopathy (ILA) had an increased incidence of constitutional signs and symptoms. Radiographic findings in both groups were indistinguishable from those of malignant lymphomas. Of all the clinical characteristics examined to establish a prognostic significance, a positive history of allergies and the presence of polyclonal gammopathy were associated with a worse prognosis. Of the 22 patients treated, 15 initially received single agents and seven combination chemotherapy. The median survival of patients who received combination chemotherapy has not been reached at 38 months, while that of the patients on single agents is 10 months. Of 9 patients who achieved complete remission, 7 remain alive, while all 14 patients who failed to achieve a complete remission have already expired. Patients initially treated with combination chemotherapy tolerated treatment well and had a more favorable outcome with only three deaths (mostly secondary to tumor recurrence) in seven patients. Even though these entities are not considered malignant morphologically, their clinical behavior frequently resembles that of a lymphomatous disorder as confirmed by the short median survival of 22 months for AIPD and 24 months for ILA. Once progressive disease is documented, we recommend combination chemotherapy as initial therapy.