June 4, 2020
A 7-year-old boy with a 3-month history of right-sided progressive facial swelling and redness of the right eye with intermittent episodes of vomiting and headache
Craniofacial Parameningeal Rhabdomyosarcoma
- Background:
- Rhabdomyosarcoma is the most common soft-tissue sarcoma in children and has a predilection for the head and neck region.
- The average age at presentation is 5–6 years.
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Genetics and associated syndromes: 11p15.512; translocations in PAX3 or PAX7 gene with FOXO1; mutations in TP53, NRAS, KRAS, HRAS and FGFR4 ; Li-Fraumeni syndrome, neurofibromatosis, Beckwith-Wiedemann syndrome, and Costello syndrome
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Types: orbital, parameningeal (PM) (nasopharynx, parapharyngeal space, masticator space, the nasal cavity, paranasal sinuses, mastoid, or middle ear), and nonparameningeal head and neck
- Clinical Presentation:
- Chronic otitis media, nasal obstruction, proptosis, headache, or cranial nerve palsies depending on the location and extension of the lesion
- Key Diagnostic Features:
- CT: Mainly used to assess skull base involvement/destruction
- MRI:
- T1: isointense to skeletal muscle
- T2: hyperintense with or without areas of hemorrhage or necrosis
- T1C+: enhancement patterns vary depending on the tumor subtype:
- homogeneous (more on the embryonal subtype), heterogeneous (alveolar and pleomorphic subtypes), ringlike (pleomorphic subtype)
- Differential Diagnoses:
- Craniofacial tumors with perineural spread: Most of these are seen above the third decade; malignant trigeminal schwannoma, squamous cell carcinoma, adenoid cystic carcinoma, mucoepidermoid carcinoma, desmoplastic melanoma (around sixth decade, nonpigmented skin or subcutaneous nodule), nasopharyngeal lymphoma (multiple enlarged nodes); all of them may have a similar appearance, so age plays an important role in prioritizing the differential diagnosis.
- Juvenile angiofibroma: Adolescent age group; intense enhancement with prominent flow voids and epistaxis; presents more with bone remodeling rather than bone destruction
- Treatment:
- Surgery, radiotherapy, and chemotherapy (vincristine, cyclophosphamide, dactinomycin, Adriamycin, ifosfamide)
- Prognosis depends on age. Factors associated with poor prognosis are age <1/>9 years, size >5 cm, PM location, histologic subtype (alveolar type), genetic mutations (PAX/FOXO1 fusion gene), regional lymph node spread, metastasis, and extension.
