TRAUMATIC FAT NECROSIS OF THE FACE IN CHILDREN

By WENDY A. BUSWELL, M.B., Ch.B. Plastic andJaw Department, The Royal Hospital Annexe, Fulwood, Shefield SIO JTD, U.K.

THIS condition is not rare, but seems to have been overlooked in the literature. It often causes confusion in diagnosis and management, particularly as most cases are seen by practitioners who are not familiar with the problem.

It usually occurs in children of the 6 to Ia-year age group, who give a history of a closed injury to the face, for example, a blow from a swing. The cheek is the common- est site, presumably due to the presence of the malar prominence; one example has been associated with a mandibular fracture. A large haematoma develops at the site of injury, and as this resolves, a firm, non-tender nodule is noticed in the subcutaneous tissue. After a year or more spontaneous resolution occurs, although a local depression may develop. This slowly fills in; permanent dimpling is unusual.

The following case is a typical example:

An Gyear-old boy had fallen from a bicycle on to his face 6 months previously, sustaining a large bruise over the right malar prominence. As the haematoma resolved, a local solid swelling was noticed under the skin, and he was referred for an excision. The obvious swelling (Fig. I) was roughly spherical, I cm in diameter, firm, non-tender and confined to the sub- cutaneous fat. It could be picked up easily between finger and thumb within the cheek fat. A diagnosis of resolving haematoma followed by traumatic fat necrosis was made, and the parents were reassured that complete resolution could be expected.

DISCUSSION

Owing to the site and nature of the condition, diagnostic excision or biopsy is not justified, so that a diagnosis is made on clinical grounds alone. Clearly, the condition is traumatic in origin, associated with a closed injury, and probably due to crushing

FIG. I

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of the subcutaneous fat between the skin and the underlying bone. Fat globules rupture, blood vessels are torn and a haematoma forms which later absorbs but leaves behind a reaction to the damaged fat. Presumably a section would show fibroblasts, macrophages and giant cells. The later development of a contour defect suggests that some of the fat has been removed. As the skin and muscle remain intact, the loss of tissue can only be in the subcutaneous fat. The eventual filling out of this defect, at least in facial injuries, suggests that regeneration of fat occurs at this site. Similar injuries to the limbs can be followed by a permanent contour defect which suggests that there are differences in the quality and blood supply of the fat at various sites.

Why the condition is seen in children and not in adults is also a matter for specu- lation.

I wish to thank Mr B. S. Crawford, Senior Plastic Surgeon to the Department, for his experienced and generous help and kind encouragement, in the writing of this article.