A case report of giant anterior neck lipoma

INTRODUCTION

Lipomas are the most common slow-growing benign mesenchymal neoplasms that can found in any location where fat is normally present. In the head and neck region, where only 13% of lipomas are seen, the posterior neck space is the most common site, but the anterior neck space is a rare location.^1,2 Here we are reporting a case of lipoma in the anterior neck.

CASE REPORT

A 50 years old male patient presented to ENT OPD with a swelling in the right anterior neck of 2 years duration. It was a slow-growing, painless mass that was not associated with any pain or overlying skin changes. No history of any previous trauma.no history of any difficulty in breathing or swallowing. The patient has taken medical advice only due to cosmetic reasons. On examination, a 11×5 cm, oval shaped, well circumscribed, soft, non-compressible, non-tender mass over the right anterior neck, seen extending vertically from the level of thyroid cartilage to the level of 2^nd intercostal space, medially till suprasternal notch and laterally till midclavicular line, that was not moving with deglutition. The skin over the swelling was normal. There was no accompanying lymphadenopathy.

Imaging studies

On ultrasonography, a homogenous hypoechoic fusiform mass of size 60×42 mm was seen encasing the right sternocleidomastoid muscle.no abnormal vascularity was seen in the mass. the mass has displaced the right carotid vessels posterolaterally.

On fine needle aspiration cytology (FNAC) findings were suggestive of lipoma. On contrast-enhanced magnetic resonance imaging (CE-MRI) of neck, T1W and T2W axial and sagittal images showed a well-defined lobulated hyper intense mass lesion measuring 9.5×4.9 cm in anterior triangle (carotid and muscular triangles) of neck on right side. It showed extension into right occipital and right supraclavicular triangle. Lesion showed hypo intense signals on fat suppressed images. No evidence of restricted diffusion seen. Post contrast scan show no enhancement.

Surgery

The patient was worked up for excision under general anaesthesia. The mass was approached via trans cervical incision along the skin crease on the right side. Subplatysmal flap were elevated. Mass was seen encapsulated and by careful dissection, it got freed from underlying sternocleidomastoid muscle and strap muscles. Complete excision with capsule has done.

Intraoperative and postoperative was uneventful. Histopathology report was lipoma.

DISCUSSION

Lipomas are benign adipose tumors of mesenchymal origin secondary to hemartomatous proliferation of mature fat cells.³ Of those lipomas that occur in head and neck region, the most common location is posterior neck while that of anterior neck is rare. Based on location, they are classified as subcutaneous type, subfascial type or intramuscular type.⁴ Based on histology, classified into simple lipoma, fibrolipoma, mixolipoma, chondroid lipoma, angiolipoma, angiomyolipoma, myelolipoma, spindle cell lipoma, sialolipoma, pleomorphic lipoma and atypical lipoma.⁵

In the head and neck region, men are more often affected than females.⁶ In a series of 25 cases of head and neck lipomas reported by Ahuja et al, 68 per cent were men, correspondingly in the series of Som et al.^7,8 52 percent of the cases reported were men. Similarly, here in our case report patient is 50 year old male.

Lipomas usually presents as solitary lesions as in our case report, but multiple site involvement may be seen in alcoholics, diabetes mellitus and syndromes such as Madelung’s disease and Kobberling-Dunningan syndromes.⁹

Although the etiology of lipoma is not well known, heredity, obesity, diabetes, trauma, radiation, endocrine disorder, insulin injection and corticosteroid therapy are occasionally implicated as possible etiological features.¹⁰ In our case report cause of this lipoma was found to be idiopathic.

Clinical features depend on the size, location and rate of growth of the lesion. Rarely lipomas reach to a size greater than 10 cm in one dimension, or weighing at least 1000 gm called as a giant lipoma.¹¹ In our case, on examination lipoma of size 11×5 cm was found in the anterior triangle of neck which is very rare both in terms of location and size.

Infiltrating lipoma is a rare variant invading muscles, vessels, nerves or deep soft tissues.¹² When presented as giant lipoma or rapidly progressing infiltrating lipoma, especially in head and neck region should be worked up for malignancy.

Classic benign lipomas often show chromosomal rearrangements of 12q14-15, 6p and 13q.9.⁵ For lipomas, the biggest challenge is differentiating a lipoma from a well differentiated liposarcoma. The absence of vacuoles in the irregularly shaped nuclei and increased size of the cells may be helpful for diagnosis of a well differentiated liposarcoma.¹³

Ultrasonography remains as the initial imaging modality in diagnosis of head and neck lipomas while FNAC or computed tomography or magnetic resonance imaging is indicated for confirmation of diagnosis.

Management is complete surgical excision as we did in our case. Asymptomatic cases can be kept under observation, they need excision if there is diagnostic uncertainty, lack of homogenicityto palpation, large neck masses (more than 10 cm), rapid growth, associated pain, deep seated locations or cosmetic concern.¹⁴ While doing excision, surgeon should be careful to remove the tumor with capsule to prevent recurrence. Liposuction is sometimes preferred especially in certain locations such as the face, as there is less scarring following the procedure but there is higher chance of recurrence, compared with excision.¹⁵

CONCLUSION

Lipomas in the anterior neck are rare, but can present as in our case. Hence lipoma should also be considered as a differential diagnosis of anterior neck swelling.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

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