Radiological Diagnosis

Sinonasal Rhabdomyosarcoma

CT Scan revealed a hypodense mass in the right nasal cavity with enlargement of the right nasal fossa, septal deviation and destruction of the alveolar margin of the maxilla. There was enhancement seen on contrast administration more marked in the peripheral part of the mass. Cytohistopathology revealed Embryonal rhabdomyosarcoma.

Rhabdomyosarcoma, the most common soft tissue sarcoma in infants and children was first described by Weber in 1854 [1]. The Head & Neck are the most common sites of origin followed by the genitourinary tract, the extremeties, trunk and retroperitoneum [2]. The peak incidence is in 2-5 years age group with a second peak between 15-19 years of age. On the basis of histopathology it is classified into four subtypes i.e. embryonal, botryoid, alveolar and pleomorphic with the embryonal form being the commonest accounting for 50-60 % of cases [3],[4].

Rhabdomyosarcoma is an aggressive bone destroying and infiltrative tumour with a propensity to spread through the neural foramina (3,4). Besides presenting as a visible mass as in the present case, rhabdomyosarcoma of the sinonasal region often presents as a relatively innocuous problem like nasal discharge, sinusitis, headache, otitis media resulting in a delay in the diagnosis (2). Most paranasal sinus rhabdomyosarcomas involve the ethmoid and maxillary sinuses. Secondary sinonasal tumours may arise from adjacent spread from orbital or pharyngeal rhabdomyosarcomas. Although imaging appearances are non specific CT and MR should be done with particular attention to bone erosions of the skull base and intracranial extension [2],[3].

Early diagnosis of rhabdomyosarcoma is imperative as untreated these tumours have high likelihood of metastasis and poor prognosis. A combination therapy including surgery, chemotherapy and radiotherapy if instituted early results in much improved prognosis [2],[3].