Natural history of malignant lymphomas with divergent histologies at staging evaluation.

The pathology and medical records of 515 patients with malignant lymphomas treated at the National Cancer Institute have been reviewed to determine the frequency and natural history of patients who have different histologic diagnoses in various tissue sites at their initial staging evaluation. Of the 101 patients who had multiple tissue sites biopsied, 33 patients had different histologic diagnoses. Eighteen patients had a nodular pattern in one site and a diffuse pattern in another. The final stage and treatment of these 18 patients were similar to that of the 27 patients with multiple identical nodular biopsies and 41 patients with multiple identical diffuse biopsies. However, the 56% complete response rate for patients with both a nodular pattern and a diffuse pattern was intermediate between that achieved in patients with identical nodular biopsies (70%) and identical diffuse biopsies (30%). Median survival for these three groups was as follows: identical nodular biopsies, 53 months; both a nodular and a diffuse pattern, 37 months; and identical diffuse biopsies, 12 months. These results demonstrate that patients with different histologic diagnoses in various sites at staging evaluation are not uncommon and have a unique natural history that should be considered in planning treatment.