Sclerosing pseudovascular rhabdomyosarcoma - Immunohistochemical, ultrastructural, and genetic findings indicating a distinct subtype of rhabdomyosarcoma
Sclerosing (pseudovascular) rhabdomyosarcoma in adults has been described as a rare variant of rhabdomyosarcoma characterized by extensive hyaline fibrosis and pseudovascular growth patterns. We describe another case of this rhabdomyosarcoma subtype including ultrastructural and genetic findings-the lesion presented in a 62-year-old male patient in the left lower leg. The tumor was located within the deep soft tissue with maximum diameter of 11.8 cm and skin ulceration. Ultrastructural analysis revealed irregularly distributed disorganized filaments without clear evidence of Z-bands and a richly collagenized matrix. Using comparative genomic hybridization, a sharply delineated loss of chromosomal region 10q22, loss of chromosome Y, and a gain of chromosome 18 (trisomy) were detected. Reciprocal translocations t(1;13) and t(2;13)(q35;q14) which are characteristic of alveolar rhabdomyosarcoma could be excluded. These findings, while showing a relation to other rhabdomyosarcoma subtypes, represent a relatively circumscribed genetic defect pattern in sclerosing (pseudovascular) rhabdomyosarcoma that is somewhat different from patterns described in most other rhabdomyosarcoma subtypes. Six months after tumor resection, the patient presented with metastatic disease. Further studies should concentrate on the identification of genes especially on chromosomal region 10q22 to elucidate more aspects in the pathogenesis of this rhabdomyosarcoma subtype.
Available from: Amandeep Kumar
- "PAX3/PAX7-FKHR gene fusion that is commonly seen in ARMS has been tested in 17 patients with SRMS including both adults and children [6, 7, 9, 11, 12, 14–16]. Only one of these patients has been found to have PAX3-FKHR gene fusion . "
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ABSTRACT: Sclerosing RMS (SRMS) is a recently described subtype of RMS that has not yet been included in any of the classification systems for RMSs. We did pubmed search using keywords "sclerosing, and rhabdomyosarcomas" and included all pediatric cases (age ≤ 18 years) of SRMSs in this review. We also included our case of an eleven-year-old male child with skull base SRMS and discuss the clinical, histopathological, immunohistochemical, and genetic characteristics of these patients. Till now, only 20 pediatric cases of SRMSs have been described in the literature. Pediatric SRMS more commonly affects males at a mean age of 9 years. Extremeties and head/neck regions were most commonly affected. Follow-up details were available for 16 patients with mean follow-up of 25.3 months. Treatment failure rate was 43.75%. Overall amongst these 16 patients, 10 were alive without disease, 4 were alive with disease, and two died. Thus, overall and disease-free survival amongst these 16 patients were 87.5% and 62.5%, respectively. The literature regarding clinical behaviour and outcome of pediatric patients with SRMSs is patchy. Detailed molecular/genetic analysis and clinicopathological characterization with longer follow-ups of more cases may throw some light on this possibly new subtype of RMS.
03/2014; 2014:640195. DOI:10.1155/2014/640195
Available from: Jody E Hooper
- "With fewer than 30 cases reported, genetic analysis has been limited. To date, only six karyotypes [5–7] and one comparative genomic hybridization  have been reported showing aneuploidy with numerous chromosomal gains but noregional amplifications [5–7]. Reciprocal translocations typical of alveolar rhabdomyosarcoma, either t(1;13)(p36;q14) or t(2;13)(q35;q14), have not been present. "
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ABSTRACT: A rare sclerosing variant of rhabdomyosarcoma characterized by prominent hyalinization and pseudovascular pattern has recently been described as a subtype biologically distinct from embryonal, alveolar, and pleomorphic forms. We present cytogenetic and molecular findings as well as experimental studies of an unusual case of sclerosing rhabdomyosarcoma. The primary lesion arose within the plantar subcutaneous tissue of the left foot of an otherwise healthy 23-year-old male who eventually developed pulmonary nodules despite systemic chemotherapy. Two genetic abnormalities identified in surgical and/or autopsy samples of the tumor were introduced into 10T1/2 murine fibroblasts to determine whether these genetic changes cooperatively facilitated transformation and growth. Cytogenetic analysis revealed a complex abnormal hyperdiploid clone, and MDM2 gene amplification was confirmed by fluorescence in situ hybridization. Cancer gene mutation screening using a combination of multiplexed PCR and mass spectroscopy revealed a PIK3CA exon 20 H1047R mutation in the primary tumor, lung metastasis, and liver metastasis. However, this mutation was not cooperative with MDM2 overexpression in experimental assays for transformation or growth. Nevertheless, MDM2 and PIK3CA are genes worthy of further investigation in patients with sclerosing rhabdomyosarcoma and might be considered in the enrollment of these patients into clinical trials of targeted therapeutics.
Sarcoma 05/2013; 2013(4):520858. DOI:10.1155/2013/520858
Available from: Liang Wang
- "So far, there are less than 40 reported cases (the present case is not included) in English literatures [3-17]. Because of its rarity, it is still unclear whether SRMS belongs to an unusual subtype of ARMS or ERMS, or even a new variant of RMS [6,8,13,17]. "
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ABSTRACT: Sclerosing rhabdomyosarcoma (SRMS) is exceedingly rare, and may cause a great diagnostic confusion. Histologically, it is characterized by abundant extracellular hyalinized matrix mimicking primitive chondroid or osteoid tissue. So, it may be easily misdiagnosed as chondrosarcoma, osteosarcoma, angiosarcoma and so on. Herein, we report a case of SRMS occurring in the masseter muscle in a 40-year-old male. The tumor showed a diverse histological pattern. The tumor cells were arranged into nests, cords, pseudovascular, adenoid, microalveoli and even single-file arrays. Immunostaining showed that the tumor was positive for the Vimentin, Desmin and MyoD1, and was negative for CK, P63, NSE, CD45, CD30, S-100, CD99, Myoglobin, CD68, CD34, CD31, and α–SMA. Based on the morphological finding and immunostaining, it was diagnosed as a SRMS. In addition, focally, our case also displayed a cribriform pattern resembling adenoid cystic carcinoma. This may represent a new histological feature which can broaden the histological spectrum of this tumor and also may lead to diagnostic confusion.
The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1615846455818924
Diagnostic Pathology 02/2013; 8(1):18. DOI:10.1186/1746-1596-8-18 · 2.60 Impact Factor
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