CT and MRI findings of different types of small round cell tumor in the nasal cavity and sinuses / 实用放射学杂志

Objective To investigate the CT and MRI findings of different types of small round cell tumor(SRCT)in the nasal cavity and sinuses.Methods A retrospective analysis was conducted on the imaging data and clinical data of 35 SRCT patients confirmed by pathology.Thirty-one SRCT patients underwent CT examination,and 19 SRCT patients underwent MRI examination.Results There were 20 cases of tumors that invaded the nasal cavity and 19 cases involved the sinuses,including 11 cases of the maxillary sinus,7 cases of the ethmoid sinus,2 cases of the sphenoid sinus,and 1 case of the frontal sinus.CT findings of SRCT were all soft tissue masses.Lymphoma was relatively homogeneous with mild bone destruction,and usually involved nasal vestibular skin.Rhabdomyosarcoma(embryonic type)happened at an early age and easily caused bone destruction and metastasis.Melanoma generally occurred in the nasal septum and nasal cavity,which was prone to bleeding.Small cell neuroendocrine carcinoma was heterogeneous,with moderate to significant enhancement,bone absorption and destruction were often noticed.The MRI manifestations of SRCT were equal or long signal on T1WI,high signal on T2WI,and significant diffusion limitation on diffusion weighted imaging(DWI)and apparent diffusion coefficient(ADC)except for melanoma.On contrast-enhanced images,lymphoma showed mild to moderate enhancement,rhabdomyosarcoma showed typical"grape sign",and small cell neuroendocrine carcinoma showed"sieve"and"map-like"obvious enhancement.Typical melanoma showed a high signal on T1WI and a low signal on T2WI and usually caused bleeding.The MRI findings were related to the presence of melanoma and hemorrhage within the lesion.Conclusion SRCT of the nasal cavity and sinuses have a high degree of malignancy and poor prognosis,CT and MRI have many similar manifestations.Combining clinical data,bone destruction,MRI enhancement,and DWI sequence can effectively distinguish different types of SRCT,as well as squamous cell carcinoma of the nasal cavity and sinuses and adenoid cystic carcinoma.