Histopathology 2017 02 22() doi 10.1111/his.13196
Plasmablastic plasma cell myeloma (PPCM) is a rare morphological presentation of multiple myeloma and can resemble plasmablastic lymphoma (PBL), an HIV related lymphoid neoplasm, morphologically and immunophenotypically. We retrospectively searched for factors that could help differentiate these two entities.
We used Clinical Looking Glass (CLG), a data mining tool, to identify patients with a diagnosis of either PPCM or PBL with a CD117 test performed.
We identified 27 cases from 16 patients in our institution with a diagnosis of either PPCM or PBL. There were 14 cases of PBL from 8 patients and 13 cases of PPCM from 8 patients. We found that 6/8 patients with PPCM were positive for CD117 while no patients with PBL (0/8) showed positivity (p=0.007 for patients). All (8/8) PPCM patients had a paraproteinemia while only 2/8 PBL patients had a paraproteinemia (p=0.007). Lytic bone lesions were more indicative of a PPCM with 6/8 patients showing these lesions while only 1/8 patients with PBL had these present (p=0.0406). HIV status was more likely positive in PBL with 6/7 patients showing positivity, while only 1/5 patients showed positivity in PPCM (p=0.072). Epstein-Barr virus encoded RNA (EBER) in-situ hybridization did not differentiate these two entities with 7/8 PBL patients showing positivity and 2/5 PPCM patients showing positivity (p=0.2168).
This study reveals that CD117 can be a useful marker to help differentiate PPCM from PBL and give the patient an appropriate prognosis and options for treatment. This article is protected by copyright. All rights reserved.