We report a rare case of a 32-year-old male with live extralymphatic filarial infestation presenting as a facial subcutaneous soft-tissue swelling. To the best of our knowledge these imaging findings have not been previously reported in the head and neck region in the existing English language literature. Real-time high-resolution ultrasonography revealed a solitary well-defined subcutaneous cystic lesion over the right zygomatic arch. It showed multiple linear, echogenic, undulating structures exhibiting a persistent twirling motion during the examination. This typical ultrasonographic appearance was consistent with the filarial dance sign (FDS) of live adult filarial worms. Subsequent MRI confirmed the cystic and solitary nature of the lesion. Complete excision of the cyst was performed, which revealed intracystic straw-coloured fluid and multiple white-coloured adult worms within the lesion. Histopathological examination confirmed multiple adult filarial worms with surrounding reactive inflammatory changes. In an endemic region, identification of the FDS in any normal anatomical structure or abnormal swelling, however remote or unusual the location within the body, should strongly suggest the diagnosis of live active filarial infestation. In view of the increasing migratory trends in the global population, it is imperative for radiologists in all countries to be aware of the typical imaging findings of this disease to arrive at the correct diagnosis.

Although previous studies have documented correlations between pre-treatment or post-treatment primary tumour volumes and local outcome following definitive concomitant chemoradiotherapy (CCRT) in head and neck squamous cell carcinoma (HNSCC), no study has included and compared tumour volumes during CCRT.

We reviewed the MRIs of 69 HNSCC patients treated with a 6 weeks course of CCRT and who underwent successful MRI pre-treatment (n = 69), 2 weeks intra-treatment (n = 48) and 6 weeks post-treatment (n = 61). Primary tumour volumes on MRI at the three time points were calculated and compared for their predictive value for primary site outcome. Volume thresholds optimised to predict failure with the highest accuracy and positive predictive value (PPV) were calculated. The mean pre-treatment volume was 24.6 cm3 (range, 1.1–187.9 cm3) and the mean follow-up interval was 41 months (range, 12–100 months). 23 primary tumours failed treatment (33%). Volumes before, during and after CCRT were positively associated with local failure (p = 0.015, p = 0.009, p<0.0001). Volume reductions during and after CCRT were negatively associated with local failure (p = 0.021, p = 0.001). Pre-treatment and intra-treatment volume thresholds achieved the highest accuracy and produced intermediate PPVs (51–64%) for predicting local failure. Optimised intra-treatment thresholds did not identify any more treatment failures than the pre-treatment thresholds. By comparison, a 6 weeks post-treatment volume reduction (<35%) achieved 100% PPV for failure, albeit with 26% sensitivity.

In conclusion, primary tumour volumetry performed early in CCRT provides minimal additional information compared with pre-treatment volumetry, with respect to predicting post-treatment local failures. Therefore, volumetry during CCRT is unlikely to be useful for guiding individual response-based therapeutic modifications.

The utility of diffusion-weighted imaging (DWI) in the detection of squamous cell carcinoma (SCC) of the tonsils has not been previously investigated. This preliminary study compared DWI of apparent SCC tonsillar tumours with normal tonsils. DWI of the tonsils was performed in 10 patients with newly diagnosed tonsil SCC that was evident on conventional MRI and in 17 patients undergoing cranial MRI for other indications. Regions of interest (ROI) were drawn around each identifiable tonsil on the apparent diffusion coefficient (ADC) map and the mean ADC value for each tonsil was calculated. ADC values for normal and SCC tonsils were compared using the Mann–Whitney U-test. The median ADC and range (×10−3 mm2 s–1) were found to be 0.814 and 0.548–1.312, respectively, for normal tonsils compared with 0.933 and 0.789–1.175, respectively, for SCC tonsils. ADC values were significantly higher for SCC tonsils than for normal tonsils (p = 0.009). No SCC tonsil had an ADC less than 0.82×10−3 mm2 s–1 compared with 58% of normal tonsils. We conclude that there is a difference in the ADC between normal tonsils and SCC tonsils where the cancer is apparent on conventional MRI. These results are promising, although further studies are now required to determine whether DWI can be used to identify or exclude smaller foci of SCC within tonsils where the cancer is not evident on conventional MRI.