ABSTRACT

The lipoma is a relatively rare maxillofacial tumor, although it occurs with considerable frequency in other areas, particularly in the subcutaneous tissues of the neck. Lipomas are common benign soft tissue neoplasms of mature adipose tissue. They have been known to grow to large sizes causing masticatory and speech difficulties. The usual lesions consist of a well circumscribed, lobulated mass of mature fat cells. In other situations the covering mucosa becomes ulcerated and presents a diagnostic dilemma and seldom occurs in the younger age group. We present a case of forehead lipoma affecting 52 year old male patient.

KEY WORDS – Lipoma , forehead , surgery

INTRODUCTION

Lipomas are benign tumors of mesenchymal origin consisting of mature fat cells which usually are involved by a thin fibrous capsule⁽¹⁾ . There are several forms and dimensions of this condition depending on location or evolution time which may cause orofacial deformity in some patients.^{( 2)} Etiology of lipoma remains uncertain, even after pointing endocrine changes and heritance factors as possible causes. It is known that lipomas are mainly present in the fifth and sixth decade of life, being rarely found during childhood .^(3,4) Lipoma’s are also seen in intra oral sites such as in lips, tongue, palate, buccal vestibule, floor of the mouth and parotid region^(1,3) . Incisional or excisional biopsy can be done in these cases. Yellow coloration of lipoma should be observed as well as fluctuation of the lesion. This lesion will be on the liquid surface due to its lower density than a fixer solution^(5,6-8). The treatment of lipomas is surgical removal. The recurrence is rare ⁽¹⁾ and there is no reported malignant transformation ⁽⁶⁾ . Although, growth of lipoma is usually limited, it can grow to large proportions which can interfere in the speech, mastication, that reinforce the necessity to realize a surgical removal.^(7,8)

The present study aims to show a rare case of forehead lipoma in the maxillofacial region.

CASE REPORT

A 52 year old male reported to the Department of Oral & Maxillofacial Surgery with the chief complaint of swelling in the forehead region which patient noticed 1 year back which had been gradually increasing initially but reported rapid growth since 1 month. On examination , a well defined 2 x 2 cm swelling was noticed in the forehead region on the right side just above the right eyebrow (Fig. 1). The skin over the swelling was stretched. No lymph nodes were palpable. On palpation, swelling was soft , fluctuant , non tender , mobile and the margins were slippery under the palpating finger. The swelling was non-pulsatile. The provisional diagnosis of lipoma was established. A differential diagnosis of dermoid cyst was excluded by negative aspiration . Routine blood investigations were carried out and were normal to plan an excisional biopsy under Local Anesthesia . Local anesthetic with adrenaline was infiltrated at the periphery of the lesion. Incision was then given along the crease in forehead to achieve better esthetic closure , crossing the swelling at its greatest bulge. Lesion was then slowly dissected out with the capsule in toto (Fig 2). Hemostasis achieved and subcuticular sutures were given (Fig. 3 & 4) so that scar is aesthetically acceptable . Histopathology report revealed a capsulated lesion with numerous adipocytes with peripherally placed nuclei. Admixed collagenic streaks were also seen.

The entire lesion was excised and no recurrence has been observed for the past 6 months and the patient is under regular follow up.

DISCUSSION–

Lipoma is a benign slow growing neoplasm composed of mature fat cells. Lipomas in the oral cavity are rare. The most common locations of lipoma in the oral cavity have been reported to be in the buccal mucosa, a region abundant in fatty tissue, followed by tongue. The hard palate has very little fatty tissue and the incidence of a lesion here is quite low. ^[9]

Lipoma differs metabolically from the normal fat cells even though they are histologically similar. It has been shown that the fat of lipoma is not used for energy production during starvation period, as it happens with normal adipose tissue, their lipid is not available for metabolism. Adipose tissue is present in two basic forms white fat and brown fat.

The clinical features of lipoma vary according to their rate of growth, size, and location. The usual complaint is of a painless palpable esthetically unpleasant mass, and there is seldom dysfunction of an involved muscle. A characteristic feature is a change in consistency and form of many of these lesions during contraction of involved muscle. The tumor is soft and flat when the muscle is relaxed and becomes firm and more spherical when muscle contracts.

The etiology varies from the differentiation of multipotent mesenchymal cells in fat tissue, cartilage, and bone to metaplasia of a preexisting lipoma. Mesenchymal cells are modified by systemic and local influences that range from local trauma to prolonged ischemia. ^[10]

Occasionally, the lipoma may invade muscles or grow between them: the so-called infiltrating lipoma. Infiltrating lipoma is an uncommon mesenchymal neoplasm that characteristically infiltrates adjacent tissues and tends to recur after excision. This type of lipoma is extremely rare in the head and neck region , and its congenital type is rare. ^[11]

Lipoma consist of mature fat cells arranged into lobules that are separated by septa of fibrous connective tissue ⁽¹²⁾. Liposarcoma is important in the differential diagnosis, because well differentiated liposarcoma often contains many areas of lipomatous tissue. Despite the close histological similarity to normal adipose tissue, lipomas, usually have chromosomal aberrations such as translocations involving 12q13-15, locus interstitial deletions of 13q, and rearrangements involving 8q11-13 locus. ^[13]

The clinical differential diagnosis includes ranula, dermoid cyst, thyroglossal duct cyst, ectopic thyroid tissue, pleomorphic adenoma and mucoepidermoid carcinoma, angiolipoma,

fibrolipoma and malignant lymphoma. The definitive diagnosis is made by means of microscopic examination which shows adult fat tissue cells embedded in a stroma of connective tissue and surrounded by a fibrous capsule. On some occasions lipoma of the buccal mucosa cannot be distinguished from a herniated buccal fat pad, except by the lack of a history of sudden onset after trauma. Lesions outside the oral cavity could show greater

recurrence rates after surgical excision.

CONCLUSION–

Lipomas found in the oral and maxillofacial region are rare and usually slow growing lesions. The clinical course is usually asymptomatic until they get larger in size. Most lipomas develop in the subcutaneous tissues but deeper tissues may be involved as well. Surgical excision is the main treatment for lipoma. The complete excision along with precautions to prevent damage to adjacent structures should be emphasized during the operation, which is the key factor in order to avoid recurrence with least morbidity.