Rhabdomyosarcomas (head and neck)

Changed by Joshua Yap, 20 Jul 2022
Disclosures - updated 15 Jul 2022: Nothing to disclose

Updates to Article Attributes

Body was changed:

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:

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:

The differential diagnosis for deeper parameningeal locations includes:

The sonographic differential also includes:

  • -</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>

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