Congenital infiltrating lipomatosis of the face: A case report with review of literature.

Congenital infiltrating lipomatosis of the face (CIL-F) has been described as a disorder in which mature lipocytes invade adjacent tissues in the facial region. Its etiology and pathogenesis is unknown. The tumor is congenital in origin and occurs in infancy or early childhood. It is unencapsulated and characterized by diffuse infiltration of mature adipose tissue over normal muscle fibers, rapid growth, associated osseous hyperplasia, and a high recurrence rate postsurgical intervention. Due to its diffuse infiltration and involvement of important facial structures, complete surgical excision is often impossible. CIL-F is rare and there are only a few cases reported in the available literature. We present the case of a 17-year-old female, who reported with the complaint of recurrent unilateral facial swelling, with a history of two previous resections.

INTRODUCTION

Congenital infiltrating facial lipomatosis (CIL-F) of the face is a subgroup of lipomatous tumours. It is characterized by diffuse infiltration of mature adipose cells over facial soft tissue, rapid growth, and osseous deformity.[1] They may occur anywhere in the body, being rare in the head and neck.[2] The incidence of congenital infiltrating lipomatosis on the face is rare, and only a few cases have been reported. It was first described as a distinct clinicopathological entity by Slavin et al. in 1983 in a patient with a unilateral swelling over the parotid region.[3] Most reported cases are in the first three decades of life.[1] The condition shows a wide phenotypic and histopathological variation.[4] All reported cases had uncertain prognosis with high rates of recurrence and variable postoperative cosmetic improvement.[5] Due to its diffuse infiltration and involvement of important facial structures, complete surgical excision is often impossible.[1]

CASE REPORT

A 17-year-old female patient presented with the chief complaint of swelling over the left side of the face since birth. The swelling gradually progressed in size over a period of time. No defects associated with vision, respiration, swallowing or other movements were reported by the patient. The patient had undergone surgical interventions for the swelling on two previous occasions, at the age of 13 and 15 years respectively. Gradual recurrence was reported two to three years after the procedure. On examination, diffuse swelling was present on the left side of the face, extending superiorly from the infraorbital area up to the lower border of the mandible, inferiorly, and medially from the midline of the face up to the preauricular area laterally. The borders were ill-defined, with a scarred surface due to previous surgeries [Figure 1a]. On palpation the swelling was soft in consistency, nontender, nonpulsatile, and non-compressive. A nevus measuring about 7 cm in size with irregular borders was noticed along the midline of the skin over the neck [Figure 1b]. Unilateral macroglossia and enlarged ipsilateral hypertrophy of the maxillary and mandibular alveolar process [Figure 1c] were observed. A previous surgical scar with an infraorbital nevus extending up to the hairline was also present [Figure 2d]. A computed tomography (CT) scan revealed hypertrophy of the left cranial vault, in the left frontal and parietal region, and a zygomatic complex with ipsilateral enlargement of the maxillary sinus and soft tissue hypertrophy on the left lower third of the face was also observed [Figure 3e]. The axial section also revealed hypertrophy of the medial pterygoid and masseter on the left side [Figure 3f]. Three-dimensional reconstruction tomography revealed left condylar hypertrophy [Figure 4g and 4h]. An incisional biopsy from the buccal mucosa, through the intraoral approach, revealed mature adipocytes, sparse myxoid areas, and inflammatory cells [Figure 5i]. Due to the recurrent nature of the swelling, the patient was referred to a higher centre for further treatment.

Figure 1

Clinical photographs—Nevus, Hyperplasia, and Macroglossia

Figure 2

Previous surgical scars and infraorbital nevus extending to the hairline

Figure 3

CT scan reveals hypertrophy of the left cranial vault in the a b left frontal and parietal region, and zygomatic complex with ipsilateral enlargement of the maxillary sinus and soft tissue hypertrophy

Figure 4

Three-dimensional reconstruction tomography reveals left condylar hypertrophy

Figure 5

Histopathology report reveals mature adipocytes, sparse myxoid areas, and inflammatory cells-H and E, ×1000

DISCUSSION

Congenital infiltrating facial lipomatosis (CIL-F) of the face is a subgroup of lipomatous tumours and diffuse neoplastic or non-neoplastic proliferation of the mature fat cells.[1] It is characterized by diffuse infiltration of mature adipose tissue over the normal muscle fibers and a rapid growth rate with associated osseous hyperplasia.[2] The term, ‘congenital infiltrating lipomatosis of the face’, was first used in 1983, when Slavin et al., reported three cases of congenital proliferating and infiltrating lesions of the adipose tissue involving the face. They described the following characteristic histomorphological findings: Infiltration of fat into the adjacent soft tissue and hypertrophy of the underlying skeleton, absence of malignant characteristics, absence of lipoblasts, presence of fibrous elements, increased number of vessels with unifocally thickened muscular walls, and increased number of nerve bundles of variable size, with focal fibrosis.[3] The etiology of this unusual tumor remains unknown.[1] Trauma, chronic irradiation, muscular metaplasia, degenerative processes with fatty transformation, multipotential cells of embryogenic origin under the influence of hormones, congenital cytomegalovirus infection, and alteration in chromosome 12, have been proposed as possible mechanisms for the lipomatous change.[3]

Unlike lipoma, CIL-F is non-encapsulated; it extensively involves the deep soft tissue, muscle, nerve, or synovium.[4] Enzinger and Weiss classified lipomatosis into three different entities: Symmetrical lipomatosis (usually in the neck), pelvic lipomatosis, and diffuse lipomatosis of the limbs and trunks.[6] This classification failed to include facial lipomatosis. Slavin et al. described the following characteristic histomorphological findings, infiltration of fat into the adjacent soft tissues and hypertrophy of the underlying skeleton, absence of malignant characteristics, absence of lipoblasts, presence of fibrous element, increased number of vessels, with unifocally thickened muscular walls, and increased number of nerve bundles of variable size with focal fibrosis.[3] Lipomatous degeneration of the face may occur at any site. Infiltrating lipomatosis of the face has been found on the cheek, buccal sulcus, tongue, lips, floor of the mouth, mental area, and parotid gland.[1] A biopsy is indicated to obtain an accurate histological identification before definitive surgery.[1] CT and magnetic resonance imaging (MRI) remain the most helpful tools for preoperative radiographic evaluation. Lipomatoses contain a large amount of fat, usually 75% of their volume, and resemble lipomas on both CT and MR imaging; but their internal septa may be broader and more nodular than those seen in lipomas. A thorough pathological examination may be required to establish the diagnosis.[7] It must be noted that an inaccurate preoperative impression may be made due to the rarity of the disease and the features of local facial swelling.[5] The differential diagnosis of lipomatosis includes several other conditions like hemifacial hypertrophy, lymphangioma, and neurofibromatosis of von Recklinghausen, with its typical café au lait spots.[7] A high rate of recurrence, ≤60% of the reported head and neck cases, is perhaps attributable to the difficulties in radical excision.[8] Kamal et al. have stated that no surgical procedure must be performed until the end of the facial growth period and mention that delaying definitive surgery has other advantages such as minimizing the chances of damage to the facial nerve, decreasing the total number of procedures, and having a mature contralateral cheek contour to match.[5]

In conclusion, complete excision is most likely to cause regrowth if done below the age of adolescence, due to the effect of growth hormones. Restoration of full facial symmetry is unlikely and the patient should be informed about the high rate of recurrence and that surgery is accompanied with a high complication rate.