NUT midline carcinoma: an imaging case series and review of literature.

BACKGROUND

NUT midline carcinoma is a rare and aggressive tumor that has primarily been reported in children and young adults. The tumor is characterized by a rearrangement on the nuclear protein in testis (NUT) gene, located on chromosome 15q14, resulting in the BRD4-NUT fusion oncogene. This carcinoma most commonly presents in the midline and displays an invariably lethal clinical course.

OBJECTIVE

To highlight the imaging features of NUT midline carcinoma.

MATERIALS AND METHODS

IRB approval was obtained for chart review. We retrospectively reviewed the chart and imaging studies of three children. All three cases were diagnosed by karyotyping and confirmed by fluorescence in situ hybridization (FISH). Cross-sectional imaging including CT, MRI and, in one patient, PET was available for review.

RESULTS

Two out of three children presented with midline and multifocal disease. The third case had a medial left thigh mass and no metastatic disease at initial presentation. The common imaging features include heterogeneous low density on CT and T1 hypointensity and low-level T2 hyperintensity on MRI with heterogeneous enhancement. All cases were confirmed pathologically and by molecular studies.

CONCLUSION

NUT midline carcinoma usually presents in the midline, either in the head, neck or chest. We present three cases with the bulk of the tumor below the diaphragm, which is seen in the minority of patients with NUT midline carcinoma, according to the available literature. Metastatic disease is common at initial presentation and can be quite extensive. The most striking feature of this disease is its aggressive nature with exponential interval growth of tumor.