Huge Intramuscular Cavernous Hemangioma involving SCM, Trapezius and scalene anterior: A Case Report

Intramuscular hemangiomas are rare benign neoplasms accounting for <1% of all hemangiomas and <20% are found in head and neck area. The muscle most frequently involved is the masseter muscle and very few cases have been reported for the occurrence of these hemangioma in the Sternocleidomastoid, trapezius muscle and scalene anterior muscles. Here, we are presenting a case report of intramuscular hemangioma involving these muscles in a 10-years-old boy.


Introduction:
The first report of a case of intramuscular hemangioma is attributed to Liston in 1843, which called this entity an "erectile tumor." Intramuscular hemangiomas (IH) are rare, benign vascular neoplasms frequently arising within the skeletal muscle of the trunk and extremities. These account for less than 1% of all hemangiomas, and head and neck involvement is considered unusual 1 . Histologically it is thought to be as harmatoma or neoplasm 2 . Generally, hemangiomas are more commonly affected female than male. They are frequently seen on the trunk and extremities, but up to 20% of hemangiomas are located at the head and neck region 2,3, . Although the majority are cutaneous or mucosal hemangioma, the intramuscular hemangiomas are extremely rare accounting for 0.8% of all hemangiomas 2, 4, 5 . Here we present a case that involved the Strenomastoid, trapezius and scalene anterior muscles. So far we believe, it is the first reported case of such involvement.

Case summary:
In 15 th jan 2017 a 10 years old cute boy was admitted in our ENT department with a Swelling in left lateral side of neck since birth.
According to the patient's mother, she noticed a neck swelling just after birth,

Fig 1(a,b): AP and lateral view
Procedure and finding: Under all aseptic precaution a schobinger incision with a lazy s on vertical limb was made and the mass was exposed by elevating the subplatysmal suprajugular flap composed of skin subcutaneous tissue and platysma (Fig.-2). initially it was very small, approximately 2x2 cm and gradually increasing in size, associated with mild low grade diffuse local pain, that does not radiate to any site. He had no problem related to the swelling, such as voice change, swallowing problem, or movement of limbs etc. except mild pain , cosmetic problem and fear of malignancy. He underwent surgery on 19 th day for this problem but the swelling remained as such.
On Examination, There was a large diffuse swelling on the left side of neck extending from the angle of the mandible upto sterna end of clavicle, posterolaterally the vertebral column, medially near the midline approximately 10 cmX8 cm , with a scar mark over the swelling (Fig: 1,2). It does not moves with swallowing The swelling was non tender, soft to firm in consistency; temperature was normal, irregular surface, approximately 10 cmX8 cm. It was free from overlying skin and underlying structure, prominent on contraction of left SCM. No palpable cervical lympahdenopathy. All the cranial nerves were intact.
After USG and FNAC our final diagnosis was cavernous hemangioma. We advised for color Doppler, MRI neck, but patient party refused due to their financial problem. Other investigations for GA were within normal limit. Operation was done on 17 th January 2017.
The mass was extremely vascular with multiple engorged veins, multilobular, bluish in color and the sternomastoid muscle was found very thin and almost engulfed by the lesion. Dissection started from midline after skeletonizing internal jugular vein (Figure 3), CCA, Xth nerve.
On further exposure the mass was found to invade the fibers of the trapezius posterolaterally and scalene muscles. Multiple branches of cervical plexus were also encircled by the tumor. Major part of sternomastoid and trapezius and was excised along with the lesion and part of involved scalene muscle can be dissected free from the lesion by bipolar diathermy. The spinal accessory nerve was encircled by the lesion so it was intentionally sacrificed. Whole lesion was excised with the help of bipolar diathermy and wound closed in layers leaving a drain tube in situ.
Postoperatively he had pain on Abduction and external rotation of shoulder. But it was significantly improved after regular physiotherapy.

Discussion:
Hemangioma are benign proliferative vascular lesions characterized by increased endothelial cell turnover that usually appears after birth, grow rapidly, and then involute over the years. Within the wide spectrum of vascular lesions, intramuscular hemangioma are very rare accounting for <1% of all Hemangioma.
The masseter muscle is the most frequent muscle, accounting for 5% of all intramuscular Hemangioma. The trapezius, periorbital, sternocleidomastoid, and temporalis muscles follow the masseter muscle in frequency 6 .
There are very few cases in the literature regarding intramuscular hemangioma involving both SCM & trapezius.
In 1843, Liston was the first to report a case of intramuscular cavernous hemangioma naming it as an "erectile tumor." Intra muscular hemangiomas are considered hamartomatous lesions and thought to arise from abnormal embryonic rests 7 .
Developmentally, intramuscular Hemangioma represents congenital vascular malformations. They generally develop in patients during the first three decades of life with no gender predispositions. Most hemangioma are recognized clinically and do not require any investigation. The predominant complaint is presence of a slowly enlarging mass 8 . Intramuscular hemangioma rarely display any clinical symptoms or signs that reveal their vascular nature. They usually presents with a normal overlying skin, although there may be occasional reddish blue discoloration. Thrills, bruits, compressibility, and pulsation are usually absent; however, pain can be present 8 . These features were also consistent with the present case.
Sonography is the first line imaging procedure for patients with soft tissue swellings. Color Doppler Sonography is especially useful to demonstrate the vascular structure. in and around the masseter muscle and has the potential to evaluate the pathological changes. Hemangioma could be distinguished from other soft tissue lesions by the features of abundant vascularity and high blood flow velocity. When performing sonography on soft tissue masses in the head and neck, the presence of a color Doppler signal in a well defined hypoechoic mass with heterogeneous echotexture should raise the possibility of hemangioma 6 .
Intramuscular hemangiomas represent a challenge on diagnosis because they exhibit few signs on clinical examination. The extent of the lesion is not always clinically apparent on examination and imaging techniques frequently define more extensive lesions than suspected 9 . Definitive preoperative diagnosis has been reported in <8% of cases 8 .
Management of intramuscular haemangioma should be individualized according to 1. Its size 2. Growth rate 3. Anatomic accessibility of the tumor, 4. Age of the patient and 5. cosmetic and functional considerations.
Complete surgical resection is preferred as a treatment of choice, but local recurrence rates have been reported as 18% and 19% in two different studies 6 .