Giant Cervico-Mediastinal Myxolipoma in a 6 Year Old Child

Lipomas are benign mesenchymal tumors, seen all over body, usually occurring in 5th and 6th decades of life [1]. 25 % of lipomas are seen in Head & Neck area and mostly in subcutaneous region, posterior triangle neck [2]. Usually slow growing, they are generally asymptomatic, till reach great size to cause cosmetic defect or pressure symptoms on surrounding structures or impair function or mobility. Lipomas greater than 10cm in width or more than 1000g in weight are called giant tumors [3].


Introduction
Lipomas are benign mesenchymal tumors, seen all over body, usually occurring in 5 th and 6 th decades of life [1]. 25 % of lipomas are seen in Head & Neck area and mostly in subcutaneous region, posterior triangle neck [2]. Usually slow growing, they are generally asymptomatic, till reach great size to cause cosmetic defect or pressure symptoms on surrounding structures or impair function or mobility. Lipomas greater than 10cm in width or more than 1000g in weight are called giant tumors [3].
Myxolipoma is one of the extremely rare histological variant of lipoma, accounting for <1% of lipomas [4], characterized by mature adipose tissue and abundant mucoid substance.
Here we report successful surgical excision of giant anterior cervical myxolipoma in a child. The rarity of this variant and huge size of the tumor in a six year old makes this interesting.

Case Report
A six year male, child, resident of Saharanpur, Uttar Pradesh, presented to our out-patient department with complaint of gradual onset, painless, progressive single, swelling neck for three years. The child had no history of breathlessness but occasional diffi culty in swallowing was present. There was no history of sudden increase in size, voice change or fever. There was no history of similar swelling in other three siblings. There was no history of previous medication or surgery for same.
On examination, the mass was 10cm X 5cmX 5cm, normal temperature, non-tender, lobulated, fi rm, fi xed to underlying structure, but free overlying normal skin, extending from chin to clavicle involving left anterior triangle of the neck, displacing trachea to the right and left common carotid anteriorly ( Figure   1). Finger could not be passed between the lower end of mass

Abstract
Lipomas are benign mesenchymal tumors that may present anywhere on the body. However, myxolipoma, the histological variant is rarely seen. We report a rare case of giant anterior cervicomediastinal myxolipoma in a 6 year old child, with discussion over diagnostic and management strategies for same. and suprasternal notch, suggesting anterosuperior mediastinal extension. There was no other palpable mass or cervical lymph node. Oral cavity examination was within normal limits.
The Chest X-ray PA view confi rmed tracheal deviation to right ( Figure 2). Fine needle aspiration cytology revealed fragments of mature adipose tissue and fi brous tissue in background with no nuclear atypia. Ultrasonography Neck revealed lobulated soft tissue mass and Doppler ruled out hypervascularity as is usually seen in malignant mass.  The patient is under follow-up for last one year, with no function loss and good cosmetic scar, without any recurrence.

Discussion
Lipoma is rarely observed in the anterior neck [5]. The fi brous capsule around, differentiates it from normal adipose tissue seen in obese people. They have slow growth and are usually asymptomatic. Numerous lipoma are mainly seen in men, while single lesion is more common in females. They are mostly seen in adult, yet some congenital lipoma has been seen [6].
Myxolipoma is a lipoma admixed with abundant mucoid substance [7]. This mucoid substance stains positively with alcian blue and gets digested by hyaluronidase. This    The exact etiology of lipoma is diffi cult to identify, but genetic, endocrine and blunt trauma are considered the most common. Rupture of the fi brous tissue and anchorage connections between the skin and deep fascia after blunt trauma may result in proliferation of the adipose tissue [8].
It is also postulated that trauma induced cytokine release triggers pre-adipocyte differentiation and maturation [9]. Lipoma are also known to be associated with various syndromes such as Gardner's (intestinal polyposis, osteomas), There are diverse methods of treatment available for lipoma. The treatment may vary from conservative like steroid injections, to cosmetic surgery like liposuction, to complete surgical excision [6]. Despite the range of treatment options available, the main treatment followed for giant cervical lipoma is complete excision, which was done in our case. Steroid injections, cause fat atrophy and are used for smaller lipomas, but they require several sitting and may even depigment the overlying skin [6]. Liposuction is also used in small lipomas, however removal of entire tumor is diffi cult and it leaves fi brous capsule [11].
Possible complications after surgery are hematoma, seroma, ecchymosis, adjacent vessel or nerve injury, fat emboli, infection and excessive scarring [5,6]. Recurrence is rarely seen, but residual is common, often due to large size, surrounding adhesions or infi ltration into adjacent muscle [6].
None of the above complications was seen in our case.

Conclusion
Myxolipoma is a rare variant of lipoma, which contains mature adipose tissue and mucoid substance. They are asymptomatic, progressive and reach huge size before patient seeks treatment. Main treatment is complete surgical excision as it avoids recurrence and other complications associated with conservative measures.

Informed consent
Written informed consent was taken from the patient parents.