MANTLE CELL LYMPHOMA - MORPHOLOGIC FINDINGS IN BONE-MARROW INVOLVEMENT

Although mantle cell lymphoma (MCL), has been well described in lymph nodes, involvement of blood and bone marrow has not been well defined. The authors reviewed involved blood and marrow specimens from 13 pati ents with MCL to determine patterns of infiltration. These findings we re compared to marrow involvement by follicular small cleared cell lym phoma (SCCL) and small lymphocytic lymphoma (SLL). Peripheral blood in volvement by MCL was present in 5 patients (38%). The circulating lymp homa cells were small (7-10 mu) with slightly folded nuclei. Marrow in volvement ranged from 5% to 90% of the marrow space and was predominan tly intertrabecular, including nodules and interstitial infiltrates (9 cases each; 68%). Paratrabecular aggregates (6 cases; 46%) and diffus e replacement by lymphoma (3 cases; 23%) were also seen. In SCCL, para trabecular involvement was seen as were interstitial nodules. Cases of SLL showed diffuse, interstitial or nodular involvement without parat rabecular localization. Cytologic comparison showed nuclei that were a ngulated in SCCL, round in SLL, and slightly irregular in MCL, with co nsiderable overlap among the groups. The architectural and cytologic f indings in marrow involved by MCL shell features of both SCCL and SLL, and cannot be used to definitively diagnose MCL.