Collision Tumors Involving Metastatic Carcinoma and Plasma Cell Myeloma: Report of Two Cases.
| Title: | Collision Tumors Involving Metastatic Carcinoma and Plasma Cell Myeloma: Report of Two Cases. |
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| Authors: | Ahmed AA; Department of Pathology, Microbiology and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA, unmc.edu.; Khalid MH; Department of Pathology and Laboratory Medicine, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas, USA, uth.edu.; Rehman AU; Department of Pathology and Laboratory Medicine, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas, USA, uth.edu.; Nguyen ND; Department of Pathology and Laboratory Medicine, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas, USA, uth.edu.; Zhang XR; Department of Pathology and Laboratory Medicine, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas, USA, uth.edu. |
| Source: | Case reports in pathology [Case Rep Pathol] 2026 Apr 25; Vol. 2026, pp. 9279261. Date of Electronic Publication: 2026 Apr 25 (Print Publication: 2026). |
| Publication Type: | Journal Article |
| Language: | English |
| Journal Info: | Publisher: Wiley Country of Publication: United States NLM ID: 101576609 Publication Model: eCollection Cited Medium: Print ISSN: 2090-6781 (Print) Linking ISSN: 2090679X NLM ISO Abbreviation: Case Rep Pathol Subsets: PubMed not MEDLINE |
| Imprint Name(s): | Publication: 2023- : [Hoboken, NJ] : Wiley; Original Publication: New York, NY : Hindawi Pub. Corp. |
| Abstract: | Synchronous coexistence of plasma cell neoplasms (PCNs) and metastatic carcinoma is not a common phenomenon and poses a significant diagnostic challenge requiring meticulous histopathological and immunophenotypic analysis for accurate lineage assignment. We report two cases of collision tumors comprising PCN and metastatic lung carcinoma. Case 1 involved a 68-year-old male with metastatic non-small cell lung adenocarcinoma who developed intracranial lesions; resection revealed metastatic adenocarcinoma intermingled with clonal plasma cells. Case 2 was a 73-year-old woman with a lytic iliac crest lesion whose bone marrow and lesion biopsies showed diffuse infiltration by both carcinoma and atypical plasma cells. Comprehensive immunohistochemical profiling, in situ hybridization (ISH), and molecular studies were performed. In both cases, histology demonstrated two distinct, intermingled cell populations without transitional features. IHC was critical for confirmation: the carcinoma cells expressed epithelial markers (AE1/AE3), whereas the plasma cell components were positive for CD138. ISH in Case 1 and flow cytometry in Case 2 confirmed clonality (kappa light-chain restriction). The final diagnoses were collision tumors of metastatic non-small cell lung adenocarcinoma with synchronous PCN (Case 1) and metastatic small cell carcinoma with synchronous PCN (Case 2). There are sporadic reports of PCN coexistent in the same lesion with solid tumors. These cases reveal the critical role of the pathologist in diagnosing collision tumors. IHC panel, including cytokeratins, CD138, and MUM1, can help in distinguishing these dual populations and avoiding diagnostic pitfalls.; (Copyright © 2026 Ahmed A. Ahmed et al. Case Reports in Pathology published by John Wiley & Sons Ltd.) |
| Competing Interests: | The authors declare no conflicts of interest. |
| Contributed Indexing: | Keywords: carcinoma; collision tumors; metastatic; myeloma; synchronous |
| Entry Date(s): | Date Created: 20260427 Date Completed: 20260427 Latest Revision: 20260427 |
| Update Code: | 20260427 |
| PubMed Central ID: | PMC13109713 |
| DOI: | 10.1155/crip/9279261 |
| PMID: | 42039856 |
| Database: | MEDLINE |
Journal Article