Indolent Lymphomas That Present With Clinically Aggressive Features: A Subset of Low-Grade Lymphomas With a Behavior Inconsistent With the Histologic Diagnosis.

BACKGROUND: The expected presentation for low-grade lymphomas consists of disseminated lymphadenopathy with no constitutional symptomsk, and with bone marrow involvement, normal lactate dehydrogenase (LDH), low proliferative rate as determined by Ki-67, and positron emission tomography (PET) scan with low standardized uptake values (SUVs) < 14. However, it is not unusual for some cases to present with 1 or more clinically aggressive features. Because the clinical behavior of such patients has not been investigated, there are no data regarding their expected outcome.

PATIENTS AND METHODS: For these cases, we use the term "clinically discordant indolent histology" (CDIH), which we define as any follicular grade 1-2, grade 3-A, or small lymphocytic lymphoma that meets at least 1 or more of the following conditions at the time of diagnosis: constitutional symptoms, LDH elevation, PET SUV > 14, unusual areas of involvement for indolent non-Hodgkin lymphoma (NHL) (bone, pleura, central nervous system, soft tissue, lung), Ki-67 > 30%, necrotic areas seen on computed tomography scan, or discrete space-occupying lesions in the liver or spleen. We have reviewed our NHL database with the objective of identifying such cases so we could compare them with those with the expected presentation of indolent NHLs.

RESULTS: Patients with CDIH have a less favorable overall survival and failure-free survival, and a higher rate of transformation to a higher-grade histology.

CONCLUSIONS: CDIH functionally behaves as aggressive NHL despite the fact that under the microscope the lymphomas resemble typical indolent NHLs. These cases seem to fare better when treated with a regimen containing doxorubicin-rituximab.