Sinonasal undifferentiated carcinoma

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Sinonasal undifferentiated carcinoma (SNUC) is a rare and highly aggressive neoplasm arising in the paranasal sinuses. It has recently been characterized as a distinct pathologic entity.

Clinical presentation

Tumors tend to be rather advanced at presentation.

Radiographic features

Tumors usually tend to be large at presentation, with poorly defined margins. Most arise within the ethmoid sinuses and superior nasal cavity. Aggressive features such as bone destruction may be seen.

CT

CECT: tumors tend to enhance in varying degrees.

MRI

Reported signal characteristics include

T1: tend to be isointense to muscle
T2: iso- to hyperintense on T2-weighted images in five patients
T1 (C+) Gd: tend to have heterogeneous enhancement

Treatment and prognosis

The prognosis for patients with SNUC is considered poor. Most centers may opt for varying degrees of craniofacial resection combined with adjuvant radiotherapy +/- chemotherapy.

Differential diagnosis

On imaging, it is almost impossible to differentiate from other tumors in this region with the possible exception of sinonasal mucosal melanoma .