Congenital infiltrating lipomatosis of the face

Congenital infiltrating lipomatosis of the face is a very rare congenital, non-hereditary disease manifesting with prominent unilateral facial overgrowth and deformity.

Clinical presentation

Facial asymmetry is always noted at birth. Other findings on the affected side include:

• unilateral skeletal hypertrophy

• capillary blush in the skin

• macrodontia

• early eruption of permanent/deciduous teeth

• macroglossia

• mucosal neuromas

Pathology

The pathogenesis of congenital infiltrating lipomatosis of the face is unclear. Recent studies proved a somatic mutation in the PIK3CA gene, which is also observed in cancers and overgrowth disorders ².

Microscopic appearance

Histological findings include:

• non-encapsulated diffuse infiltration of mature adipose tissue into the adjacent muscles and soft tissue

• presence of fibrous component

• presence of nerve bundles in different sizes, and vessels with thickened wall

• absence of lipoblasts

Associations

In rare cases, associated ipsilateral brain malformations have been described ³, including:

• ipsilateral hemimegalencephaly

• band heterotopia

• hemihypertrophy of the ipsilateral brainstem and cerebellum

Radiographic features

Plain radiograph

• hypertrophy of facial bones

• soft tissue swelling

• dental anomalies

CT

CT can demonstrate the lipomatous nature of the mass, its relationship to adjacent structures and osseous changes. Diffuse fat tissue infiltration (−60 HU to −120 HU) and maxillofacial bone hyperplasia can be seen. Fatty infiltration can be inhomogeneous, with a feathery appearance due to intervening fibrous elements.

MRI

MRI is also very specific for identification of fat tissue and provides a better delineation of the extent of infiltration.

Inhomogeneous high signal intensity of the lesion on T1 and T2 weighted images and low signal intensity on fat-suppressed T2 images can be seen.

Treatment and prognosis

Treatment is usually with surgical excision with a high propensity for recurrence.

History and etymology

This entity was first described by Slavin et al. in 1983 ¹.

Differential diagnosis

The differential diagnosis for unilateral facial enlargement includes:

• encephalocraniocutaneous lipomatosis

• Proteus syndrome

• congenital hemifacial hyperplasia

• vascular malformations

• benign and malignant tumors

• congenital lymphedema

• segmental odontomaxillary dysplasia