Cytogenetic study of malignant triton tumor: a case report
Introduction
Malignant peripheral nerve sheath tumors (MPNST) constitute 5%–10% of malignant soft tissue tumors. Karyotypes of these tumors are often complex, with both numerical and structural changes described for all chromosomes [1]. MPNST with muscle differentiation is also known as malignant triton tumor (MTT) [2]. Relatively mature rhabdomyoblasts are scattered throughout a stroma resembling classic MPNST [3]. This rare variant of MPNST is often seen in patients with neurofibromatosis 1 (NF1) and typically involves the head, neck and trunk [4]. Few chromosome analyses of MTT exist. We report here comprehensive cytogenetic analyses of a case of MTT occurring in an individual without recognized NF1.
Section snippets
Case history
An 81-year-old male who was known to have Paget disease of the bone was incidentally found to have a 15-cm retroperitoneal mass. At laparotomy a large left abdominal mass was present with solid and cystic components. Small and large bowel was adherent to the mass, and several peritoneal implants were observed. Pathology showed a metastatic malignant triton tumor. Histologically, the tumor was biphasic with areas of MPNST showing tactoid differentiation and rhabdomyosarcoma. Immunohistochemistry
Cytogenetic analysis
Short-term culture was performed on the metastatic tissue using standard methods to obtain metaphases. The tumor specimen was mechanically and enzymatically disaggregated using collagenase (Worthington type II, 400 μg/mL) for 2–4 hours. The resulting cell suspension was cultivated in RPMI-1640 medium (BioWhittaker, Walkersville, MD, USA) supplemented with 20% fetal bovine serum, penicillin 100 U/mL, streptomycin 100 μg/mL, and 2 mmol/L l-glutamine (Gibco, Grand Island, NY, USA) in an atmosphere
Results
Thirty-seven metaphases (20 G-banded and 17 SKY) were analyzed. Thirteen metaphases had an apparently normal karyotype, whereas the remaining 24 had structural and numerical abnormalities. In spite of the biphasic morphology of the tumor, the cytogenetic analyses revealed a composite karyotype with consistent markers. Some markers were relatively constant while others were highly variable. Clonal loss of chromosomes 8, 17, 19, 20, and 22 was observed, though SKY revealed portions of some of
Discussion
The cell of origin of MTT is not known, though the presence of both neural cells and rhabdomyoblasts have led some to hypothesize that both cellular components derive from less differentiated neural crest cells that have both mesodermal and ectodermal potential and thus possess the ability to develop both skeletal and neural components [7]. Direct evidence for the potential of schwannoma cells to exhibit myogenic differentiation has been shown [8].
Cytogenetic analyses of MTT are limited;
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Cited by (29)
Malignant triton tumor of the rectum – A case report and review of the literature
2020, International Journal of Surgery Case ReportsMalignant triton tumor of the gluteal region in a patient unaffected by neurofibromatosis: A case report
2018, Acta Orthopaedica et Traumatologica TurcicaCitation Excerpt :The pathogenesis of MTT is unknown, the presence of both neural cells and rhabdomyoblasts have led some to hypothesize that both cellular components derive from less differentiated neural crest cells that have both mesodermal and ectodermal potential and others points out direct evidence for the potential of schwannoma cells to exhibit myogenic differentiation.6 Masson and Martin initially postulated that divergent myoid differentiation could occur in neoplastic neuroectodermal cells but there are it seems likely that both cell lines originate from less well-differentiated neural crest cells.7,8 Cytogenetic studies reveal certain abnormalities in these tumors including common breakpoints in Chr 7, 11 and loss of Chr 22.5,8
Malignant peripheral nerve sheath tumors: Prognostic impact of rhabdomyoblastic differentiation (malignant triton tumors), neurofibromatosis 1 status and location
2013, European Journal of Surgical OncologyCitation Excerpt :In our current study, cases of MTT and MPNST seen at our institution were directly compared. The largest study on MTT included 124 patients which were all collected from literature review9; most other studies include a small number of cases from their own institutions with a literature review for additional patients1,8,11–13 or consist of single case reports.7,10,14 The two large series of MPNST contain 134 and 175 patients, respectively, however, these did not specifically analyze the MTT subgroup.5,6
A Triton tumor mimicking sacrococcygeal teratoma
2009, Journal of Pediatric SurgeryCitation Excerpt :The main causes of death are tumor recurrence and metastases commonly to lung and brain [14]. Patients with complete tumor resection receiving adjuvant therapy tend to fare better than those who undergo incomplete resection with adjuvant therapy [1-3,5-7]. Malignant Triton tumor is a highly aggressive relatively rare tumor and complete resection of this tumor with or without adjuvant therapy tends to portend improved survival.
Neural and neuroendocrine tumors
2009, Weedon's Skin Pathology: Third EditionMalignant triton tumor of the prostate: MRI findings
2008, European Journal of Radiology ExtraCitation Excerpt :The clinical course is usually one of rapid growth, early metastases, and poor outcome in spite of therapy. Most metastases were located in the brain or lung and 80% of patients with metastases died within 1 year [3,4,9]. The diagnosis of MTT was suggested from light microscopic examination.