Sclerosing pseudovascular rhabdomyosarcoma - immunohistochemical, ultrastructural, and genetic findings indicating a distinct subtype of rhabdomyosarcoma
ABSTRACT 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.
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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
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ABSTRACT: Sclerosing rhabdomyosarcoma (SRMS), a recently characterized variant of rhabdomyosarcoma, can pose a significant diagnostic challenge given its rarity and its histological similarity to other malignancies. SRMS is characterized by dense hyalinized or sclerosing collagenous matrix and a pseudovascular pattern of growth. SRMS shares histologic similarities with several mesenchymal tumors including: leiomyosarcoma, osteosarcoma, chondrosarcoma, angiosarcoma, and sclerosing epithelioid fibrosarcoma. We herein report a case of SRMS mimicking a myoepithelial carcinoma of the parotid gland. The tumor contained small, spindled, and epithelioid tumor cells lining pseudovascular spaces within a dense hyalinized stroma. Initial stains for keratins, S100 and p63 were negative. However the tumor cells showed desmin and myogenin positivity. The tumor was negative for FKHR gene rearrangements and showed no MDM2 gene amplification. This is the second case of SRMS to be diagnosed in the parotid gland highlighting the potential for misdiagnosis as a primary salivary gland epithelial malignancy.Head and Neck Pathology 04/2014; 9(1). DOI:10.1007/s12105-014-0540-x
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ABSTRACT: Recently, spindle cell/sclerosing rhabdomyosarcoma (RMS) has been recognized as another distinct variant of a RMS. We evaluated clinicopathological features of 21 cases of spindle cell and sclerosing RMS and performed fluorescent in situ hybridization (FISH) testing in 10 (47.6%) tumours. Twenty-one tumours occurred in 16 males and 5 females (mean age, 19.7 years); commonly in the head and neck region (8) (38%) and extremities (7) (33.3%), followed by paratesticular region (2) (9.5%), chest wall (1), abdomen (1), pelvis (1) and paraspinal region (1). Average tumour size was 7.9 cm. Histopathologically, tumours that were spindle cell type (8) (38%) mostly occurred in the head and neck region, while sclerosing type (10) (47.6%) mostly occurred in the extremities. Remaining three (14.2%) tumours were mixed (sclerosing with spindle cell type). Tumour areas resembling embryonal RMS (ERMS) and alveolar RMS (ARMS) were noted in eight and three tumours respectively. Immunohistochemically, tumour cells were positive for desmin (21/21) (100%), MyoD1 (19/19) (100%), myogenin (13/15) (86.6%), SMA (2/3) and MIC2 (1/8) (12.5%). On FISH testing, none of the 10 tumours exhibited RMS1 (PAX3-FOXO1) or RMS 2 (PAX7-FOXO1) fusion. Eighteen patients underwent surgical resection and were offered adjuvant chemotherapy (CT) (4 cases), adjuvant CT + radiotherapy (RT) (4 cases) and adjuvant RT (1 case). Two patients underwent CT and a single patient received CT + RT. On follow-up (16 cases) (2–36 months), six tumours recurred and nine metastasized. Spindle/sclerosing RMSs are aggressive tumours and occur commonly in the head and neck and extremity sites. These tumours are histopathologically interrelated. Their immunohistochemical and cytogenetic profile is closer to ERMS than ARMS.Apmis 04/2014; 122(11). DOI:10.1111/apm.12272 · 1.92 Impact Factor