CT and MRI features of extraocular muscle granular cell tumour: preliminary experience in eight cases

Intramuscular granular cell tumor in the sternocleidomastoid muscle: A case report and literature review

Granular cell tumor (GCT) is a rare soft-tissue neoplasm that originates from Schwann cells. Most cases occur in the subcutaneous or submucosal regions, and intramuscular GCT is even more uncommon. Herein, we describe an atypical GCT growing in the sternocleidomastoid muscle. A 41-year-old Chinese man was admitted to our hospital for a right neck mass. In magnetic resonance images, the mass showed higher signal intensity than the adjacent normal muscle on T2-weighted images and intermediate signal intensity on T1-weighted images. Slightly enhanced and higher signal intensity was observed in the peripheral rim on contrast-enhanced fat-sat T1-weighted images, and the "stripe sign" was evident. The tumor was completely resected, and pathological examination indicated an atypical GCT. The patient tolerated the procedure well. This is a rare case report of an intramuscular GCT from diagnosis to treatment. Magnetic resonance imaging might help diagnose such tumors, and we review different magnetic resonance imaging characteristics of intramuscular GCTs at other sites.

Proposing a quantitative MRI-based linear measurement framework for response assessment following stereotactic body radiation therapy in patients with spinal metastasis

PURPOSE

To provide evidence towards a quantitative response assessment framework incorporating MRI-based linear measurements for spinal metastasis that predicts outcome following stereotactic body radiation therapy (SBRT).

METHODS

Adult patients with de novo spinal metastases treated with SBRT between 2008 and 2018 were retrospectively assessed. The metastatic lesions involving the pedicles, articular processes, lamina, transverse process, spinous process and vertebral body at leach level were measured separately using linear measurements on pre- and all post-SBRT MRIs. The outcome was segment-specific progression (SSP) using SPINO guidelines which was dated to the first clinical documentation of progression, or the date of the associated MRI if imaging was the reason for progression. Random forest analysis for variable selection and recursive partitioning analysis for SSP probability prediction were used.

RESULTS

Five Hundred Ninety-three spinal levels (323 patients) from 4081 MRIs were evaluated. The appearance of new T1 hypointensity and increase in Bilsky grade had an odds ratio (OR) of 33.5 and 15.5 for SSP, respectively. Compared to baseline, an increase of > 3 mm in any lesion dimension, combined with a 1.67-fold increase in area, had an OR of 4.6 for SSP. The sensitivity, specificity, positive predictive value, negative predictive value, balanced accuracy and area under the curve of the training model were 96.7%, 89.6%, 28.6%, 99.8%, 93.2% and 0.905 and of the test model were 91.3%, 89.3%, 27.1% 99.6%, 90.3% and 0.933, respectively.

CONCLUSION

With further refinement and validation in prospective multicentre studies, MRI-based linear measurements can help predict response assessment in SBRT-treated spinal metastases.