Conference Abstracts - 2026 National Summit on Hematologic Cancers
Vol. 6, Issue Supplement 2, 2026 · S1-2
Cyclin D1–Negative, SOX11-Positive Pleomorphic Mantle Cell Lymphoma: A Case Report and Systematic Review of the Literature
Sundas Ali, MD, MBBS,Ranjeet Kumar, MD,Abat Khan, MD, MBBS,Aliya Khan, MD, MBBS,Ihsane Ouansafi, MD,Jose D. Sandoval-Sus, MD
Submission received: 2026-08-15 / Accepted: 2026-08-25 / Published: 2026-09-25
Abstract
Background
Mantle cell lymphoma (MCL) is typically characterized by cyclin D1 overexpression resulting from IGH::CCND1 rearrangement. Rare cyclin D1-negative pleomorphic variants can closely mimic CD5-positive diffuse large B-cell lymphoma (DLBCL), creating a major diagnostic challenge. We report a localized SOX11-positive case and systematically review the diagnostic roles of SOX11 and CCND2/CCND3 alterations.
Methods
PubMed, Google Scholar, Cochrane Library, and Embase were searched in July 2026 using terms related to cyclin D1-negative MCL, SOX11, CCND2, and CCND3. Of 264 identified records, 12 publications reporting original cases or case series met the inclusion criteria.
Results
A 72-year-old man presented with progressive, painless left cervical lymphadenopathy. PET/CT showed disease confined to the left cervical nodes. Biopsy demonstrated a pleomorphic CD5-positive, CD20-positive, lambda-restricted B-cell lymphoma with Ki-67 greater than 90%. The tumor was cyclin D1-negative and SOX11-positive, without IGH::CCND1, MYC, BCL2, or BCL6 rearrangements. Expert hematopathology review favored pleomorphic MCL over CD5-positive DLBCL. Bone marrow biopsy and gastrointestinal endoscopy were negative. Treatment with four-weekly rituximab doses, 36-Gy involved-site radiation, and maintenance rituximab resulted in a complete metabolic response (Deauville score 1). Across included publications, SOX11 was the most consistently reported diagnostic marker, whereas CCND2/CCND3 testing varied considerably. Localized pleomorphic presentations were uncommon. Cohort overlap and inconsistent molecular testing prevented reliable enumeration of unique cases.
Conclusion
Cyclin D1-negative pleomorphic MCL can closely mimic CD5-positive DLBCL. SOX11 expression, integrated with morphology, immunophenotype, and molecular findings, can support diagnosis but is not entirely specific. Standardized evaluation of SOX11 and CCND2/CCND3 alterations may improve recognition of this rare, aggressive subtype.