Sternocleidomastoid tumor of infancy: two cases of an interesting entity

Rare Concurrence of Congenital Muscular Torticollis and a Malignant Tumor in the Same Sternocleidomastoid Muscle

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.

Shear wave sonoelastography in infants with congenital muscular torticollis

Congenital muscular torticollis (CMT) is characterized by shortening or excessive contraction of the sternocleidomastoid muscle (SCM). The main purpose of this study was to evaluate the feasibility of quantifying SCM stiffness using acoustic radiation force impulse (ARFI) sonoelastography in infants with CMT. Twenty infants with an SCM thickness greater than 10 mm with or without involvement of the entire SCM length (limitation of neck rotation passive range of motion [PROM]: group 1S >30°, group 1M = 15°-30°) and 12 infants with an SCM thickness smaller than 10 mm with or without involvement of any part of SCM (group 2) were included. The SCM thickness was measured using real time B-mode ultrasound, and the local SCM shear wave velocity (SWV) and subcutaneous fat layer using ARFI sonoelastography. The neck rotation PROM was significantly greater in group 1S (36.5° ± 5.3°) than in group 1M (18.8° ± 4.9°; P < .01); the SWV of the SCM in the affected side (2.96 ± 0.99 m/s) was significantly higher than that in the unaffected side (1.50 ± 0.30 m/s; P < .01) in group 1. The SWV of the SCM was significantly higher in group 1S than in group 1M. There was significant correlation between the degree of PROM deficit of neck rotation and the SWV of the affected SCM (r = .75; P < .01) in all infants. This study revealed a difference in the SWV of the affected SCM in relationship to the limitation of neck rotation PROM in infants with CMT, if there was no difference in SCM thickness among infants.

Rapid spontaneous resolution of fibromatosis colli in a 3-week-old girl

Fibromatosis colli is an uncommon benign, congenital fibrous tumor or pseudotumor of the sternocleidomastoid muscle that manifests in infancy. In some of these patients tightening of the muscle results in torticollis. We report the case of a 3-week-old child, who presented with a neck mass localized in the left side with reduced mobility of the head. The diagnosis of fibromatosis colli was raised by ultrasound sonography. The mass regressed spontaneously within 3 months without surgical or physical treatment.

Magnetic resonance imaging as a determinant for surgical release of congenital muscular torticollis: correlation with the histopathologic findings

OBJECTIVE

(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.

METHOD

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.

RESULTS

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.

CONCLUSION

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.

Diagnosis of sternomastoid tumor of infancy by fine-needle aspiration cytology

Sternomastoid tumor of infancy, also known as fibromatosis colli or muscular torticollis, is a benign fibroblastic lesion of the sternocleidomastoid muscle presenting as a firm, fusiform, non-tender neck mass of 1-3 cm in greatest dimension in the perinatal period. Various modalities are used for the diagnosis including radiographic studies, fine-needle aspiration cytology (FNAC), and open biopsy. We report eight cases of sternomastoid tumor of infancy diagnosed by FNAC. The objective of the study is to present the role of FNAC in the diagnosis of sternomastoid tumor with its cytomorphological features. FNA was done by using 23-guage needle and 10 ml disposable plastic syringe. The wet smears were fixed in 95% ethanol and processed for Papanicolaou stain. The dried smears were stained with May-Grünwald-Giemsa stain. The smears were studied for cytomorphologic features. The age of the patients ranged between 2 and 10 weeks. Male: Female ratio was 1.6:1. Six of eight had history of prolonged labor, two had history of breech presentation, and three had history of forceps assisted vaginal delivery. Cytologic findings included singly scattered and loose clusters of benign fibroblasts with moderate amount of unipolar to bipolar cytoplasm and plumped, ovoid nuclei. Many multinucleated giant cells consistent with atrophic muscle fibers were also seen. FNAC is a reliable, safe, and cost-effective method and can provide a rapid and reliable diagnosis of sternomastoid tumor of infancy.

Management of birth injuries

Birth injuries are a significant cause of neonatal morbidity and mortality. Although often associated with traumatic delivery, birth injuries often occur in normal spontaneous deliveries in the absence of any risk factors. This article discusses the diagnosis and management of the most common birth injuries that are encountered by health care providers who care for newborns.

Management of birth injuries

Birth injuries are a significant cause of neonatal morbidity and mortality. Although they are frequently associated with traumatic delivery, birth injuries often occur in normal spontaneous deliveries in the absence of any risk factors. This article discusses the diagnosis and management of the most common birth injuries encountered by health care providers caring for newborns.

Magnetic resonance imaging in the evaluation of infantile torticollis

This retrospective study assessed the use of magnetic resonance imaging (MRI) in 58 infants with infantile torticollis. Eighteen patients had nonmuscular causes of torticollis (group 1); MRI identified lesions in 16 patients. Of 40 patients with a diagnosis of congenital muscular torticollis (group 2), 28 had a normal MRI. Five patients had asymmetry of the sternocleidomastoid without noticeable signal changes. Seven patients showd evidence of fibromatosis colli. Asymmetry of the posterolateral skull consistent with plagiocephaly was common. Magnetic resonance imaging did not alter treatment of group 2. Findings of compartment syndrome of sternocleidomastoid were inconsistent. Magnetic resonance imaging is not recommended for asymptomatic patients with infantile torticollis.

Bilateral sternocleidomastoid tumor of infancy

The sternocleidomastoid tumor of infancy (STOI), also known as fibromatosis colli, presents as a firm well circumscribed mass within the sternocleidomastoid muscle (SCM) in infants of 1-8 weeks of age. Some of these lesions are associated with torticollis, facial and cranial asymmetry. Incidence of STOI is approximately 0.4% of live births and usually 90% of the patients will have a good prognosis if therapy is initiated and continued for the appropriate period of time. This paper presents two cases of bilateral involvement of STOI, which is very rare. The bilateral nature of the masses added to the uncertainty of the clinical diagnosis and the unusual features of these cases are discussed.