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Smith MH, Moynihan J. Ectomesenchymal chondromyxoid tumor of the oral cavity: a report of 5 new cases with comprehensive review of the literature and clinicohistopathologic features. Oral Surg Oral Med Oral Pathol Oral Radiol 2023; 135:410-426. [PMID: 36739213 DOI: 10.1016/j.oooo.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/02/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE An ectomesenchymal chondromyxoid tumor (ECT) is an uncommon soft tissue tumor with an enigmatic histogenesis and striking predilection for the tongue. We present 5 new cases and review the literature. STUDY DESIGN We performed a retrospective search for ECTs within the University of Kentucky Oral Pathology Biopsy Service and the published literature. RESULTS Five new cases from the biopsy archives and 103 well-documented ECT cases from the literature were compiled and reviewed. Whereas 89.8% of ECT are found on the anterior/dorsal/lateral/unspecified tongue, 4.6% are on the posterior/base of tongue. Six extralingual cases are reported. The age ranges from 2.3 to 78 years with an average of 40. Most ECT react with GFAP (92.8%) and S-100 protein (91.3%). Whereas 21/23 cases demonstrated a RREB1-MKL2 fusion, EWSR1 gene mutations are identified in 4 cases. CONCLUSIONS Most ECT are readily diagnosed on routine histopathology in combination with tumor site, immunohistochemical findings, and molecular findings; however, a subset share overlapping features with myoepithelioma of soft parts. As further molecular analysis is performed on this tumor, we may find that a subset of previously diagnosed ECT relate to or represent myoepithelioma or conversely fall under the spectrum of the pluripotent ECT.
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Affiliation(s)
- Molly Housley Smith
- Department of Oral and Maxillofacial Pathology, University of Kentucky College of Dentistry, Lexington, KY, USA.
| | - Jack Moynihan
- Department of Oral and Maxillofacial Pathology, University of Kentucky College of Dentistry, Lexington, KY, USA
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Agaimy A, Din NU, Dermawan JK, Haller F, Melzer K, Denz A, Baumhoer D, Stoehr R, Grützmann R, Antonescu CR. RREB1::MRTFB fusion-positive extra-glossal mesenchymal neoplasms: A series of five cases expanding their anatomic distribution and highlighting significant morphological and phenotypic diversity. Genes Chromosomes Cancer 2023; 62:5-16. [PMID: 35763541 DOI: 10.1002/gcc.23082] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 11/09/2022] Open
Abstract
The RREB1::MRTFB (former RREB1::MKL2) fusion characterizes ectomesenchymal chondromyxoid tumors (EMCMT) of the tongue. Only five molecularly confirmed extra-glossal EMCMT cases have been reported recently; all occurring at head and neck or mediastinal sites. We herein describe five new cases including the first two extracranial/extrathoracic cases. The tumors occurred in three male and two female patients with an age ranging from 18 to 61 years (median, 28). Three tumors were located in the head and neck (jaw, parapharyngeal space, and nasopharyngeal wall) and two in the soft tissue (inguinal and presacral). The tumor size ranged from 3.3 to 20 cm (median, 7). Treatment was surgical without adjuvant treatment in all cases. Two cases were disease-free at 5 and 17 months; other cases were lost to follow-up. Histologically, the soft tissue cases shared a predominant fibromyxoid appearance, but with variable cytoarchitectural pattern (cellular perineurioma-like whorls and storiform pattern in one case and large polygonal granular cells embedded within a chondromyxoid stroma in the other). Two tumors (inguinal and parapharyngeal) showed spindled to ovoid and round cells with a moderately to highly cellular nondescript pattern. One sinonasal tumor closely mimicked nasal chondromesenchymal hamartoma (NCMH). Mitotic activity was low (0-5 mitoses/10 hpfs). Immunohistochemical findings were heterogeneous with variable expression of S100 (2/5), EMA (2/3), CD34 (1/4), desmin (1/4), and GFAP (1/3). Targeted RNA sequencing revealed the same RREB1::MRTFB fusion in all cases, with exon 8 of RREB1 being fused to exon 11 of MRTFB. This study expands the topographic spectrum of RREB1::MRTFB fusion-positive mesenchymal neoplasms, highlighting a significant morphological and phenotypic diversity. Overall, RREB1::MRTFB-rearranged neoplasms seem to fall into two subcategories: tumors with lobulated, chondroid, or myxochondroid epithelioid morphology (Cases 2 and 3) and those with more undifferentiated hypercellular spindle cell phenotype (Cases 1, 4, and 5). Involvement of extracranial/extrathoracic sites and the NCMH-like pattern are novel. The biology of these likely indolent or benign tumors remains to be verified in the future.
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Affiliation(s)
- Abbas Agaimy
- Institute of Pathology, Friedrich Alexander University Erlangen-Nürnberg, University Hospital, Erlangen, Germany
| | - Nasir Ud Din
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Josephine K Dermawan
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
| | - Florian Haller
- Institute of Pathology, Friedrich Alexander University Erlangen-Nürnberg, University Hospital, Erlangen, Germany
| | - Katja Melzer
- Institute of Radiology, Friedrich Alexander University Erlangen-Nürnberg, University Hospital, Erlangen, Germany
| | - Axel Denz
- Department of Surgery, Friedrich Alexander University Erlangen-Nürnberg, University Hospital, Erlangen, Germany
| | - Daniel Baumhoer
- Institute of Pathology, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Robert Stoehr
- Institute of Pathology, Friedrich Alexander University Erlangen-Nürnberg, University Hospital, Erlangen, Germany
| | - Robert Grützmann
- Department of Surgery, Friedrich Alexander University Erlangen-Nürnberg, University Hospital, Erlangen, Germany
| | - Cristina R Antonescu
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
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