Acquired facial lipoatrophy: A report of 3 cases with imaging features (2025)

Abstract

Acquired facial lipoatrophy is a rare disease with an unclear etiology and pathological pathway. The distinct causative factors of this disease have been not elucidated, but it is suspected to be associated with immune system-related diseases, most notably AIDS. Although the management of facial lipoatrophy is very important for patients' social life and mental health, no treatment framework has been developed due to the unknown nature of the disease manifestation. The present case report was designed to provide sequential imaging to visualize the disease progression. The clinical backgrounds of the patients are also introduced, helping characterize this disease entity more clearly for maxillofacial specialists.

Introduction

The facial contour is affected more strongly by the volume of subcutaneous fat tissue than by the underlying anatomic structures, bone, and musculature. The symmetrical and adequate distribution of subcutaneous fat tissue is considered essential to an aesthetically pleasing face.1 Lipoatrophy of the face is an uncommon disease that involves a reduction in facial adipose tissue, causing abnormal indentation and asymmetry of the face.2,3 People with facial lipoatrophy may experience low self-esteem, depression, and social isolation.2

Facial lipoatrophy can occur due to natural or pathological processes.3 Natural or physiological lipoatrophy refers to the loss of facial fat due to senescence.2 This type of adipose tissue loss generally starts at the age of 20 to 30 years and progresses gradually. Natural lipoatrophy is usually bilateral. In contrast, when pathological adipose tissue loss occurs, patients may lose their facial symmetry to a serious degree within a short time. Common sites of adipose tissue loss are the cheeks, temples, and pre-auricular region.

Currently, the molecular pathways contributing to the manifestation of this disease remain unclear. Several contributing factors are known, and the most commonly established cause is infection with HIV. The treatment for this disease (antiretroviral therapy), as well as HIV infection itself, can trigger inflammation of the subcutaneous adipose tissue, causing the subcutaneous fat to shrink in volume.3 Lupus erythematosus is another systemic disease that causes the inflammatory loss of subcutaneous adipose tissue, known as panniculitis. Localized scleroderma also involves panniculitis, although it initially is characterized by an inflammatory erythematous patch.3

Until recently, due to the ambiguity and rarity of facial lipoatrophy, neither standard clinical criteria for diagnosis nor proper treatment options had been established for this condition.4,5 However, studies of facial atrophy have been regularly reported in the literature, and the symmetry of the facial contour has become more important for many people in terms of managing their social life and mental health in modern society.2,3,4,5 The present case report aimed to provide information about this rare disease of unclear origin to oral and maxillofacial specialists and to help characterize this disease entity more clearly.

Case Report

Discussion

Facial lipoatrophy is not life-threatening; however, patients' psychosocial health can be considerably affected by this condition. Two of the patients described in the present report visited our hospital with reports of facial depression, and the other patient had incidentally detected facial atrophy. The known causes of lipoatrophy are immune system-related diseases, including HIV infection, lupus erythematosus, and localized scleroderma.3 Those diseases were not present in the patients discussed in this report. In contrast, the patient in case 2 had adrenal deficiency and ESRD, while the patient in case 3 had mild anemia and was rheumatoid factor-positive. Scant previous research has been presented regarding an association between those diseases and lipoatrophy.4,5 A case report with a literature review published in 2004 stated that, of 220 cases, only 1 patient had facial lipoatrophy associated with rheumatoid arthritis.4,5 This report also suggested an association between lipoatrophy and renal disorders, especially membranoproliferative glomerulonephritis (MPGN), as the 220 cases included 45 cases of lipoatrophy (approximately 22%) with histopathologically proven MPGN. MPGN is a type of glomerulonephritis that may progress into renal dysfunction, including ESRD.6 However, the studies covered in that review were focused on the onset of renal disease due to lipoatrophy, the precise mechanism of which is not yet clear. The patient in case 2 had suffered from renal disease for 15 years, whereas the lipoatrophic changes had taken place more recently. It is thus difficult to conclude that the renal disease developed as a consequence of lipoatrophy; however, the patient's renal condition did require close examination, since it could have become severe (with a poor prognosis) due to the sudden onset of lipoatrophic changes.

Osteomyelitis was noted on the left mandible of the patient in case 2 after tooth extraction. Misra et al. noted that infection may be a preceding factor of lipoatrophy.5 The most commonly reported infectious disease preceding lipoatrophy is measles, although 1 report has described lipoatrophy of the face within a few weeks after tooth extraction.5,7 In case 2, on the follow-up CT images, the subcutaneous and intermuscular fat layers of the head and neck region showed a diffuse increase in attenuation, which is a sign of inflammation. Such general inflammatory changes of the subcutaneous layer were not observed in the other 2 patients, in whom only a severe loss of fat volume was demonstrated. Considering that the patient in case 2 had systemic diseases that were closely related to the immune system, the infection may have spread extensively, making it a possible preceding factor for lipoatrophy.

Unlike the patients in case 2 and 3, the patient in case 1 was relatively young and healthy and had no apparent systemic disease. According to the 2003 study conducted by Misra et al., facial lipoatrophy without any evidence regarding etiology was the most common type reported in the literature.8 The patient in case 1 was also different from the other patients in that he had discomfort in the affected facial region. Specifically, he complained of muscle spasm and tenderness on the left side of the face during chewing. Lipoatrophy in the extremities presenting with muscle pain has been reported, but those cases were confirmed to be myositis on MR images.9 However, the electromyogram and MR images of the patient in case 1 showed no specific pathologic findings associated with his facial and masticatory muscles. Although his left cheek had completely lost its subcutaneous fat tissue and his skin was slightly thinned, the ipsilateral masseter muscle maintained its original volume and showed a normal signal compared to that on the right side. The parotid gland on the affected side showed inflammatory and atrophic changes as its volume decreased, and the hilar region was contrast-enhanced on the CT images. Moreover, also on the CT images, the left Stensen duct was thickened and contrast-enhanced, which is a sign of sialodochitis.10 According to previous research, significant and rapid fat loss may cause increased tightness, with the skin positioned directly on the facial bone.3 An individual may feel discomfort due to this abnormal tension of the skin.3 This inflammatory changes of the duct and gland may be due to stenosis of the main duct caused by facial skin tension. The presence of tenderness when chewing may also be explained by these inflammatory changes in the duct and gland. Still, whether this explanation is relevant to this case is uncertain, because the patient felt that the frequency of involuntary muscle spasms in the masseter muscle decreased after an injection of anesthetic into the masseteric branch of the mandibular nerve. This suggests that his symptoms may have been neurogenic. Progressive facial hemiatrophy, which is known as Parry-Romberg syndrome, is a neurocutaneous syndrome involving the progressive loss of the subcutaneous adipose tissue in the facial region innervated by the fifth cranial nerve.11,12 The disease varies from mild to severe. In the mild type, the facial depression is barely perceptible, while in the severe type, facial disfigurement is prominent and involves the underlying bone and muscle.12 The pathogenesis of this disease is not well known. Genetic alterations during embryogenesis, viral or bacterial infections, and traumatic nerve injury have been proposed as etiologies. In a previous study, 45% of patients exhibited migraine and/or facial pain due to trigeminal neuralgia.12 Some patients have been reported to exhibit lipoatrophic changes involving the salivary gland, as in one of the present cases.13 Parry-Romberg syndrome is very rare (1 case per 700,000 individuals) and usually occurs in the first or second decade of life, whereas our patient was older.12 However, the clinical manifestations of our patient were similar to those of this disease, meaning that this syndrome cannot be completely ruled out and further clinical observation is required.

In conclusion, lipoatrophy of the face is an uncommon disease that seems to be associated with various inherited or acquired systemic diseases. A system for the diagnosis and grading of this disease has been established recently, although a framework for treatment is still absent. Thus, oral and maxillofacial specialists should be aware of this entity and perform careful examinations to determine if it is related to an unknown systemic or infectious disease in affected patients. Patients should be carefully followed up with because lipoatrophy may interrupt renal function. Additionally, it is important to correct the disfigurement, since asymmetric facial contour can lead to social stigma and negative psychological effects on patients.

Footnotes

References