Bilobed lipoma of submandibular region: an unusual presentation.

Abstract

A 55-year old male patient presented to the Department of Oral and Maxillofacial Surgery with a swelling of the right submandibular region since four years [Table/Fig-1]. Swelling was painless asymptomatic and gradually increasing in size. On palpation swelling was firm with well-defined margins approximately (7x4 cm), swelling was mobile not fixed to overlying skin and no sign of inflammation. Patient was systemically normal. A tentative diagnosis was formed based on clinical examination which includes non-specific enlargement of right submadibular gland, lipoma, and lymphoma. [Table/Fig-1]: Clinical picture of lipoma in right submandibular region Contrast CT of right submandibular region showed a well circumscribed bilobed mass with mild extension into the parapharynegal space [Table/Fig-2] which was suggestive of benign lipomatous condition. A decision was made to surgically explore the lesion. [Table/Fig-2]: Contrast CT scan of the right submandibular region revealing the bilobed Tumour mass with mild extension into the parapharyngeal space After obtaining pre anaesthetic clearance, patient was admitted for excision of mass under GA [Table/Fig-3]. A submandibular incision was given to create access to soft tissue mass blunt dissection was done preserving marginal mandibular branch of facial nerve and a yellowish bilobed soft encapsulated mass was excised [Table/Fig-4,​,5].5]. Postoperative recovery was uneventful. Histological examination under 5 x magnifications showed sheets of mature adipocytes and lobules of adipose tissue separated from the surface epithelium by fibrous connective tissue stroma. The adipocytes were loosely arranged in large areas which showed presence of empty cytoplasm and small nuclei. Tumour cells were arranged in lobules. These lobules were separated from each other by fibrovascular connective tissue septae [Table/Fig-6]. [Table/Fig-3]: Outline of submandibular incision along with marking of inferior border of the mandible in order to save the marginal mandibular nerve during dissection [Table/Fig-4]: Intraoperative view of bilobed lesion separated from surrounding structures [Table/Fig-5]: Completely excised lesion along with parapharyngeal extension [Table/Fig-6]: Depicting the mature adipocytes and fat lobules separated by fibrous septae The presence of lipoma in the submandibuar region is extremely rare and it accounts for only 1-2% of all lipomas of the body. Angiolipomas and infiltrating lipomas are rarely found in the oral cavity [1] . There have been reports of deep intra muscular lipoma in the submandibular region by Adachi et al., [2] . Pusiol e t al., reported an oncocyticsialo lipoma of submandibular gland [3] . Diagnostic imaging techniques such as ultrasonograpghy, MRI and CT help to differentiate lipomas from other soft tissue lesion. And helps to identify the nature and exact location of lesion. However, the soft tissue characterization with ultrasonography is less specific than CT or MRI. When the mass is difficult to identify on ultrasonogram, CT or MRI is necessary. On CT scan it shows a high density from 83 to 143 Hounsfield units with well or poorly defined margins depending on the capsule [4].