Malignant lymphomas of follicular center cell origin in humans. V. Incidence, clinical features, and prognostic implications of transformation of small cleaved cell nodular lymphoma.

Seventy-five cases of small cleaved cell nodular lymphoma (SCC-N) were reviewed. Thirty-four cases underwent repeat biopsy a median of 54 months after diagnosis (range, 7-116 months) because of progressive or recurrent disease. Histologic conversion to a transformed (noncleaved) cell lymphoma was found at re-biopsy in 13 of 34 cases (38%). Neither age, gender, stage, visceral sites of disease, nor symptoms at presentation were predictive of subsequent conversion. Similarly, none of the clinical features analyzed at the time of rebiopsy were predictive of whether the rebiopsy would show stable histology or transformation. Documentation of transformation was of significant prognostic value. Although rebiopsies were performed at the time of progressive disease, survival following re-biopsy was 37.5 months for patients found to have cleaved cell lymphoma at re-biopsy, and only 2.5 months for those with transformed cell lymphoma at re-biopsy. Two of the cases which had immunoglobulin surface markers studied at diagnosis and at transformation, showed retention of heavy and light chain markers. This implies that the change in appearance involves the original neoplastic clone and was not due to a second neoplasm. Development of transformed cell lymphoma is one of the most common features of the aggressive phase of indolent lymphoma. Repeat biopsy in all patients with indolent lymphoma who have relapsing or progressive disease is recommended.