While congenital muscular torticollis (CMT) can occur along with other conditions, such as clavicle fracture or brachial plexus injury, these conditions exist outside the sternocleidomastoid muscle (SCM). We present a rare case with concurrence of CMT and a malignant tumor inside the same SCM, along with serial clinical and radiological findings of the atypical features of CMT. The malignant tumor was in fact a low-grade fibromyxoid sarcoma. To the best of our knowledge, the current case is the first of a concurrent condition of CMT inside the SCM. This case suggests that concurrent conditions could exist either inside or outside the SCM with CMT. Therefore, a thorough evaluation of SCM is required when subjects with CMT display atypical features, such as the increase of mass or poor response to conservative therapy. In that case, appropriate imaging modalities, such as ultrasonogram or magnetic resonance imaging, are useful for differential diagnosis.
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(1) To present the magnetic resonance imaging (MRI) findings of congenital muscular torticollis (CMT) of subjects who underwent surgical release and subjects who showed a good prognosis with stretching exercises and (2) to correlate the MRI findings with the histopathologic findings of CMT for subjects who underwent surgical release in order to examine the hypothesis that the MRI findings of CMT can be used as a determinant to perform surgical release of CMT.
The neck MRI findings of 33 subjects who underwent surgical release for CMT were compared with those of 18 subjects who were successfully managed only with conservative management. The MRI findings were correlated with the histopathologic sections of the CMT mass.
All 33 subjects (100%) who underwent surgical release showed one or more low signal intensities within the involved sternocleidomastoid muscle (SCM) on the T1- and T2-weighted images of neck MRI. The eighteen non-surgical candidates showed only enlargement of the SCM without low signal intensity within the SCM. The histopathologic findings showed interstitial fibrosis and/or the presence of aberrant tendon-like excessive dense connective tissue that was either well-arranged or disorganized.
The histopathologic findings and MRI findings showed good correlation in terms of the amount of fibrosis and aberrant dense connective tissue within the SCM. If multiple or large low signal intensities within the SCM are noted, we think that surgical release should be considered.
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