A rare cause of horner syndrome: pediatric lipoblastoma of the neck.

To the Editor: Less than 10% of soft tissue neoplasms in the first and second decades of life have an adipose phenotype, and most are benign. The most common are various types of lipoma and lipoblastoma. Lipoblastomas originate from embryonal fat tissue. Even if biologically benign, these neoplasms can be difficult to resect completely because of their undefined margins. The recurrence rates are between 14% and 24%. In the literature, there are few published case series of lipoblastoma/lipoblastomatosis. Lipoblastomatosis has been defined as the diffuse multifocal type of lipoblastoma. The majority of these tumors occur superficially in the subcutaneous tissues of the extremities and trunk and rarely at other sites including the face, scrotum, parotid gland, and mediastinum. In the head and neck, these lesions are extremely rare. Histologically, lipoblastomas are now categorized into two types, the encapsulated and diffuse types. Cervical lipoblastoma typically presents as a rapidly enlarging, painless neck mass. Symptoms, however, can occur from compression of cervical structures, including Horner syndrome, hemiparesis, and respiratory compromise. Diagnosis is often suggested by CT and MRI findings but can only be confirmed by microscopic examination. The recommended treatment is complete surgical excision. An 8-month-old girl presented with a 2-month history of an enlarging, painless, left side neck mass and at the same side drooping of the eyelid (Figs. 1A, B). There was no history of trauma, infection, dysphagia, dyspnea, stridor, or fever. Medical history was unremarkable. Physical examination revealed a welldeveloped and well-nourished child with a semi-mobile, rubbery mass, approximately 5 cm in diameter, located in the left anterolateral side of the neck, starting 2 cm inferiorly of the angulus mandibulae and extending along the sternocleidomastoid (SCM) muscle. It was nontender and nonerythematous. At the same side with mass, left eye had ptosis, myosis, and enopthalmos. MRI research demonstrated a well-defined 5.3 3.5 3.7-cm mass in the anterolateral region of the neck with anterior displacement of the carotid artery and compression of the trachea and esophagus (Fig. 2). Mass was isointense on T1-weighted images and hyperintense on T2-weighted images. Fine-needle aspiration biopsy revealed fibroadipose tissue. Surgical excision via a lateral cervical approach demonstrated a well-encapsulated, soft, yellowish-white mass deep to the SCM muscle. The mass was successfully dissected away from the prevertebral fascia and cervical sympathetic ganglion chain and lung apex at the inferior (Fig. 3). Pathological evaluation of the tumor demonstrated immature adipocytes surrounded by myxoid material, and lobulation characteristic of lipoblastoma (Fig. 4). At 2 years of follow-up, the child is healthy and developing normally without recurrent tumor. Ptosis, myosis, and enopthalmos of the left eye completely healed. Lipoblastomas are rare benign tumors arising from embryonal white fat cells typically found in the axilla, mediastinum, retroperitoneum, prevertebral areas, and extremities, with only few cases reported in the neck (6). Most of them occur before 3 years of age. Lipoblastomas can present anywhere in the body, but most of the lipoblastomas occur mainly in the extremities and the trunk and have rarely been described in the head and neck area. In the head and neck area, cervical region was the most common location, and the parotid gland, the cheek, the skin, and the orbit were also reported. Lipoblastomas of the neck are frequently asymptomatic. The most common presentation of cervical lipoblastoma is a rapidly growing, painless mass. However, in some cases, as the tumor became larger, it could compress the adjacent structures and cause specific symptoms such as respiratory insufficiency, Horner syndrome, and weakness of the upper extremity. According to the review of 48 cervical lipoblastoma cases from 1982 to 2009, Pham et al reported that the most common presenting symptoms for neck lipoblastomas were painless enlarging neck mass (53%) and respiratory distress (12%). They found out 1 case presenting with Horner syndrome. O’Donnell et al also reported a lipoblastoma case with Horner syndrome. CT and MRI can be used to identify lipoblastomas. MRI may be chosen because there is no radiation and the mass can be seen with high signal intensity in T1and T2-weighted images. But the definitive diagnosis is always pathological examination of the mass. We did not have any recurrence so far in this case, but local recurrences up to 25% are reported. When treating head and neck masses in children, we must always keep in mind that differential diagnosis is crucial. Cystic hygroma/lymphangioma, vascular anomalies, mature lipoma, liposarcoma, lipofibroma, and thyroglossal duct cysts are to be considered and differentiated in pediatric masses. This case shows us that although lipoblastoma is a rare and pathologically benign tumor, it is important to consider it in differential diagnosis of neck masses due to its critical anatomical localization. Lipoblastoma is better known in the last 15 years, but