DISTINCTION BETWEEN DIFFUSE CUTANEOUS MALIGNANT FOLLICULAR CENTER CELL LYMPHOMA AND LYMPHOID HYPERPLASIA BY COMPUTERIZED NUCLEAR IMAGE-ANALYSIS

The difficult differential diagnosis between the diffuse variants of c utaneous lymphoid hyperplasia (CLH; synonym: pseudolymphoma) and malig nant follicular center cell lymphomas (FCCL) often requires a multidis ciplinary approach. Eighteen CLH and 11 FCCL, diagnosed by conventiona l histology and immunophenotyping and subsequently examined with a pol ymerase chain reaction to show clonal immunoglobulin heavy-chain gene rearrangements, were subjected to a novel type of automated nuclear im age analysis. Of all nuclear parameters tested in azure A-stained semi thin sections, the mean nuclear profile area (TN) of lymphoid cells wa s the best criterion to distinguish between CLH and FCCL (p = 9 X 10(- 6)). Additional distinctive features, in the order of decreasing signi ficance, were the SD of TN; all chromatin textural parameters combined ; and the light and the dark fractions of the central nuclear profile areas. Parameters related to the chromatin pattern were independent of nuclear profile size in FCCL, but not in CLH. Two lesions registered as CLH displayed the nuclear characteristics favoring this diagnosis, but showed B-cell monoclonality at the DNA level. In conclusion, compu terized nuclear image analysis is a helpful additional diagnostic tool in the evaluation of diffuse CLH and cutaneous FCCL.