186 Cytologic Diagnosis of a Rare Case of Plasmacytic Neoplasm With Cyclin D1 and CD20 Positivity. (11th January 2018)

• Record Type: Journal Article
• Authors: Harinath, Lakshmi; Mohanty, Alok; Silverman, Jan
• Is Part Of: American journal of clinical pathology. Volume 149(2018)Supplement 1
• Page Start: S79
• Page End: S79
• Publication Date: 2018-01-11
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqx121.185
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: Plasma cell neoplasms (PCNs) are lymphoproliferative disorders arising from post germinal center B cells with somatic hypermutations that exhibit varied manifestations and can be a challenging diagnosis for clinicians and pathologists. A subset of PCN reveals translocations of chromosome 14 involving the immunoglobulin heavy chain locus (IgH) with specific clinicopathological features with prognostic implications that have not been well characterized. We present to you the case of a 69-year-old man with mid back pain that radiated to his chest. Imaging of the thoracic spine revealed heterogeneous enhancement of both T6 and T11 vertebrae, after which he underwent a CT-guided biopsy of the T6 vertebra. The touch preparation and core biopsy revealed extensive infiltration by small-sized plasmacytic cells in a paratrabecular pattern. Immunohistochemistry revealed these cells to be positive for CD138, CD20, Bcl-2, MUM1, and cyclin D1, and negative for CD45, CD3, CD5, CD10, and Bcl-6. In situ hybridization (ISH) for kappa and lambda demonstrated lambda light chain restriction leading to a diagnosis of plasmacytic neoplasm with features most consistent with a CD20-positive plasmacytoma/myeloma. Fluorescence ISH revealed polysomy of odd-numbered chromosomes, chromosome 17 abnormalities, and the CCND1/IGH fusion gene in 71% of the examined cells. Although CD20 positivity in PCN with t(11, 14) is well documented and has considerable therapeutic implications, it becomes very difficult to distinguish the present case from a B-cell lymphoma with plasmacytic features. Some studies show a worse prognosis for translocation-associated PCN, while other studies do not support this finding. Since PCNs present with heterogeneous morphology, clinical features, and immunohistochemical and molecular profiles, extensive work-up and clinicopathologic correlation is essential for appropriate classification and management.