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Case history

Image not available. A 15-year-old boy was referred to ENT with a 2 month history of swelling over his left nasal labial region. It had initially been thought to be an acne cyst but had continued to grow despite antibiotics. The patient was systemically well and examination was otherwise unremarkable. There was nothing of note in his medical history or family history.

Examination under anaesthesia found a 15 mm friable swelling adherent to the ala cartilage. Histology indicated soft tissue overrun by a small-round-blue-cell tumour suggesting, from cytology, an alveolar rhabdomyosarcoma. This diagnosis was confirmed by the finding of a 2;13 translocation on fluorescence in situ hybridization (FISH) analysis. Staging was performed via CT chest, isotope bone scan and bilateral bone marrow aspirate and trephines, all of which showed no further evidence of disease.

The cancer was staged as an Intergroup Rhabdomyosarcoma Study Group (IRS) group II (postsurgical) rhabdomyosarcoma. In accordance with the RMS-2005 trial,1 in which he was in the high-risk group, the patient gave informed consent and was randomized to urgent chemotherapy with ifosfamide, vincristine and dactinomycin (IVA). A restaging MRI after three cycles showed response, but there was a residual mass at the original site measuring 11 mm × 14 mm in axial dimension. There was no evidence of disease elsewhere. The patient underwent a left hemimaxillectomy, with clear surgical margins, followed by postoperative concurrent radiotherapy 41 Gy in 23 fractions.

He received a further six cycles of adjuvant IVA chemotherapy with minimal toxicity before being randomized to 6 months of maintenance chemotherapy with oral cyclophosphamide and weekly vinorelbine. On completion of chemotherapy he underwent biannual review in clinic. Seven years later he remains disease free, has graduated from university and has been discharged from the acute service to late effects review.

What are small-round-blue-cell tumours?

What are the characteristics of rhabdomyosarcomas?

How do patients typically present and how are they investigated?

How does molecular stratification aid treatment decisions?

Where is more research needed?

What are small-round-blue-cell tumours?

Small-round-blue-cell tumours are a group of malignancies characterized by small, round, relatively undifferentiated cells. Included within this category are Ewing's sarcoma, peripheral neuroectodermal tumour, rhabdomyosarcoma, synovial sarcoma, non-Hodgkin's lymphoma, retinoblastoma, neuroblastoma, hepatoblastoma and nephroblastoma. Small-cell osteogenic sarcoma, undifferentiated hepatoblastoma, granulocytic sarcoma and intra-abdominal desmoplastic small-round-cell tumour are further differentials. It can be difficult to reliably differentiate between these entities on the basis of traditional histology and modern immunohistochemistry. The precise diagnosis is necessary for optimal therapy. Cytogenetic translocations therefore often define the diagnosis. Table 13.1 lists known translocations in sarcoma subtypes.2

Table 13.1Known translocations in sarcoma subtypes.2

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