Rhabdomyosarcomas (head and neck)
Updates to Article Attributes
Rhabdomyosarcomas of the head and neck represent a large proportion (~40%) of all rhabdomyosarcomas and are the most common soft tissue sarcomas of the head and neck. For a general discussion of this tumour, please refer to rhabdomyosarcoma.
Pathology
There are usually of the embryonal in cell subtype and are essentially only seen in children. They are classified by location into:
- orbital rhabdomyosarcoma: good prognosis (90% long term survival)
- para-meningeal rhabdomyosarcoma: worse prognosis (50% long term survival)
- other head and neck locations
Middle ear rhabdomyosarcomas are rare, accounting for only 7% of head and neck rhabdomyosarcomas. They typically present similarly to chronic otomastoiditis and are usually diagnosed too late for curative treatment. Frequently (30%) cranial nerve involvement is present at the time of diagnosis.
Microscopic appearance
Histologically, rhabdomyosarcomas are low-grade small round blue cell tumours. Ewing sarcoma, neuroblastoma, and lymphoma share similar characteristics that make histopathologic differentiation of rhabdomyosarcoma hard.
Radiographic features
Ultrasound
Rhabdomyosarcomas resemble neuroblastomas in echotexture and often demonstrate low to medium echogenicity. With colour Doppler, there is often variable internal vascularity.
MRI
- T1: isointense to slightly hyperintense
- T2: hyperintense
- T1 C+: marked contrast enhancement
- +/- intralesional
hemorrhagehaemorrhage or necrosis - +/- diffusion restriction
Radiology report
As the differential diagnosis is vast, and the imaging findings are non-specific, it would be useful to describe in detail the:
- location
- involvement of adjacent compartments
- perineural, vascular, and osseous involvement
- presence of lymphadenopathy
Treatment and prognosis
Treatment depends on the location and disease extent, with orbital and non-parameningeal head and neck locations having a better prognosis. Chemotherapy is first line for the treatment of rhabdomyosarcomas, with radiation therapy and surgery utilised for local tumour control.
Differential diagnosis
The differential diagnosis for more superficial non-parameningeal locations includes:
- chondrosarcoma
- fibrosarcoma
- synovial sarcoma
The differential diagnosis for deeper parameningeal locations includes:
-
hemangioendotheliomahaemangioendothelioma - nasopharyngeal carcinoma
- osteosarcoma, and primitive neuroectodermal tumour
The sonographic differential also includes:
- fibrosarcoma
- malignant fibrous histiocytoma
- angiosarcoma
- neurofibrosarcoma
-</ul><p>Middle ear rhabdomyosarcomas are rare, accounting for only 7% of head and neck rhabdomyosarcomas. They typically present similarly to <a href="/articles/chronic-otomastoiditis">chronic otomastoiditis</a> and are usually diagnosed too late for curative treatment. Frequently (30%) cranial nerve involvement is present at the time of diagnosis.</p><h5>Microscopic appearance</h5><p>Histologically, rhabdomyosarcomas are low-grade small round blue cell tumours. Ewing sarcoma, neuroblastoma, and lymphoma share similar characteristics that make histopathologic differentiation of rhabdomyosarcoma hard.</p><h4>Radiographic features</h4><h5>Ultrasound</h5><p>Rhabdomyosarcomas resemble neuroblastomas in echotexture and often demonstrate low to medium echogenicity. With colour Doppler, there is often variable internal vascularity.</p><h5>MRI</h5><ul>- +</ul><p>Middle ear rhabdomyosarcomas are rare, accounting for only 7% of head and neck rhabdomyosarcomas. They typically present similarly to <a href="/articles/chronic-otomastoiditis">chronic otomastoiditis</a> and are usually diagnosed too late for curative treatment. Frequently (30%) cranial nerve involvement is present at the time of diagnosis.</p><h5>Microscopic appearance</h5><p>Histologically, rhabdomyosarcomas are low-grade <a title="Small round blue cell tumours" href="/articles/small-round-blue-cell-tumours">small round blue cell tumours</a>. Ewing sarcoma, neuroblastoma, and lymphoma share similar characteristics that make histopathologic differentiation of rhabdomyosarcoma hard.</p><h4>Radiographic features</h4><h5>Ultrasound</h5><p>Rhabdomyosarcomas resemble neuroblastomas in echotexture and often demonstrate low to medium echogenicity. With colour Doppler, there is often variable internal vascularity.</p><h5>MRI</h5><ul>
-<li>+/- intralesional hemorrhage or necrosis</li>- +<li>+/- intralesional haemorrhage or necrosis</li>
-<li>hemangioendothelioma</li>- +<li>haemangioendothelioma</li>
-<a href="/articles/osteosarcoma">osteosarcoma</a>, and <a href="/articles/primitive-neuroectodermal-tumour-of-the-cns">primitive neuroectodermal tumour</a>- +<a href="/articles/osteosarcoma">osteosarcoma</a>, and <a href="/articles/primitive-neuroectodermal-tumour-of-the-cns-historical">primitive neuroectodermal tumour</a>