patients with ismcl are limited. ismcl has been found to have been present 2–86 months prior to patients developing mcl but only 1 of 15 patients who were followed for >1 year developed the malignance. it has been suggested that mutations in the atm and chk2 genes may be associated with an increase risk of, and/or a shorten time before developing, mcl. in situ lymphoid neoplasia patients who have or develop fl, mcl, or other lymphoid malignancy are treated for their malignancies.