Abstract
Fibromatosis colli is a rare disease related to congenital muscular torticollis that responds well to therapy if diagnosed and treated early. Gray-scale ultrasonography is used for diagnosis and follow-up, but with limitations. A novel technique, real-time elastography, might prove helpful for evaluating the response to therapy. A case is presented of fibromatosis colli diagnosed with sonography and real-time elastography in the first month of life. The baby was treated with physiotherapy for 3 months, and therapy was ended on the basis of real-time elastographic findings. Real-time elastography has been shown to be useful in the diagnosis and follow-up to physiotherapy for fibromatosis colli.
Fibromatosis colli is generally defined as a palpable mass in the body of the sternocleidomastoid muscle (SCM). This mass causes shortening of the long axis of the SCM and restricts the movement of the neck; it appears as congenital muscular torticollis (CMT) in clinical practice. 1 Imaging studies such as magnetic resonance imaging and sonography display a mass lesion in the SCM as a result of fibrosis due to intrauterine malposition, fetal delivery trauma, or infection affecting the central nervous system.1,2 Nonsurgical treatment methods are effective, and most patients improve by the end of the first year of life.
Children are commonly diagnosed and followed up with gray-scale sonography, 3 but sonography has a limited ability to determine the response to therapy. Real-time elastography (RTE), based on the displacement of tissues under compression, can be used to evaluate the stiffness of mass lesions, which can help clinicians in the diagnosis, treatment, and follow-up of the disease. The elasticity of hard tissue is less than soft tissue under appropriate compression, and an elastogram can be projected over a gray-scale sonographic image as a color-coded image on the right side of the image with the gray-scale sonogram on the left side.4,5 Here we report a case of fibromatosis colli diagnosed in an infant in the first month of life, with the use of RTE in the follow-up of fibromatosis colli treatment.
Case Report
A female infant in the first month of life presented with a palpable, mobile, 3 × 1 cm mass on the right side of the neck. Neck motions were restricted, and the face and chin were rotated to the left side, while her face was tilted to the right side. There was no history of fetal intrauterine malposition, central nervous system infection, or fetal trauma on vaginal delivery. Bilateral hip sonography of the baby was normal. Gray-scale sonography and RTE were done using an Aplio 500 ultrasound system with a high-frequency 7- to 18-MHz linear-array transducer (Toshiba Corporation, Tokyo, Japan). The gray-scale sonogram of the neck showed a 25 × 10 mm hypoechoic, heterogeneous mass in the substance of the right SCM (Figure 1). The thickness of the left SCM was normal at 0.4 mm by gray-scale sonography. The strain of the mass lesion on the right SCM was less, indicating increased hardness, than the strain of the left SCM on RTE (Figures 2a and 2b).
Long axis gray-scale image showing a hypoechoic, heterogeneous mass in the substance of the right sternocleidomastoid muscle (arrows).
(a) Side-by-side images of the colorized sonoelastogram of the mass in the right sternocleidomastoid muscle (SCM), which shows as mostly blue, indicating a hard lesion, and the corresponding gray-scale image (mass indicated by white star). (b) Side-by-side images of the colorized sonoelastogram of the left SCM, which shows as mostly yellow-green, indicating average tissue hardness, and the corresponding gray-scale image of the left SCM (SCM indicated by white stars).
The infant was treated with physiotherapy, including flexion, extension, rotation, and massage of the neck. At the end of the second month of physiotherapy, there was a 30% decrease in the diameter of the mass on the right SCM (2 × 0.7 cm) by gray-scale sonography, and the strain noted for the mass in the right SCM (Figure 3) was similar to the original control values of the left SCM (Figure 2b). Physiotherapy was considered completed at the end of the third month without need for surgical intervention because of free neck movement on physical examination and the noted increase in the elastic properties of the mass.
Side-by-side images at the end of the second month of therapy showing the colorized sonoelastogram of the right sternocleidomastoid muscle (SCM), which shows as mostly red to yellow-green, indicating average tissue hardness, and the corresponding gray-scale image (SCM indicated by arrows).
Discussion
CMT is a deformity of the neck in neonates or infants causing lateral inclination of the head. 2 Patients can present with restricted neck motion, facial asymmetry, tilt of the head, and palpable mass. There are two forms of the disease, according to the presence or absence of a mass in the SCM. This mass is likely to be palpable on physical examination and is termed fibromatosis colli; it is the most common reason for CMT.1,2 This hard mass in the body of the SCM causes the muscle to shorten and tighten, causing movements of the neck to be restricted. Patients are generally diagnosed in the first week or month of life. 2 Fetal malposition and fetal delivery trauma have been implicated in CMT, and congenital hip dysplasia is the most frequently detected associated anomaly (though none of these was a factor in the case presented).1,2 Most patients improve by the end of the first year of life with early physiotherapy, but a small number of patients require surgical intervention.1,2,6 Studies have shown that the beginning time of early physiotherapy is important and significantly affects the need for surgical intervention, but surgical release therapy for a stretched SCM can be done if there is not a good response to physiotherapy.2,6
Fibromatosis colli results in a palpable mass that can be seen as a hypoechoic, heterogeneous mass by gray-scale sonography, and it generally is easily differentiated from other neck pathologies, such as lymphadenopathy, congenital cystic masses of the neck, and hematoma. 7 An increase or decrease in the size or area of the affected part of the SCM can also be easily displayed by sonography; however, gray-scale sonography has a limited ability to show the hardness of the affected SCM or smoothing of the treated SCM. These are important considerations for the efficacy of physiotherapy, for prognosis, and especially for any decision regarding surgical intervention. 8
RTE is a novel technique, but one that is now widely available on state-of-the-art ultrasound systems. It can be used to assess the elastic properties of a mass lesion in the SCM before and after nonsurgical treatment, without the need for any contrast agent or interventional methods such as muscle biopsy.4,5,9 It can be performed as a complement to gray-scale sonographic evaluation using the same transducer. Typically on the displayed elastogram, a red color indicates a soft target, while a blue color indicates hard tissue. Yellow and green colors indicate midrange hardness, which represents an approximate average stiffness of the tissue. In the current medical literature, there are few studies concerning the elasticity properties of CMT. 9 RTE may have a limited role and have no remarkable advantage over gray-scale sonography in the initial diagnosis of CMT, but it does provide a baseline for the stiffness or hardness of the affected tissue. With this information, RTE may play a more important role in determining the efficacy of physiotherapy and deciding on the need for surgery.3,9
Conclusions
Sonography is widely used in the diagnosis and follow-up of CMT and can display the SCM and differentiate other soft tissues in the neck. Although sonography is sufficient for the diagnosis of CMT, it has limited ability to show differences in the stiffness of the fibromatosis colli, which could provide important new information concerning the type and duration of therapy. RTE is a novel technique that can complement gray-scale sonographic examination using the same probe. By displaying the stiffness of the fibromatosis colli before and after various treatment methods, RTE can be helpful in the overall management of CMT.