A case of lipoma of the submandibular region extending into parapharyngeal space

INTRODUCTION Lipoma is one of the most common forms of benign non-epithelial tumor found anywhere on the body. In the head and neck, it comprises 10% of all lipoma. It arises mainly in the posterior cervical triangle and forehead. Reports of lipoma extending into the parapharyngeal space, are extremely rare: in fact they represent only 1-2% of all of the parapharyngeal space tumor. We present a case of lipoma that extended into the parapharyngeal space which was removed with small invasion using a transcervical approach. CASE REPORT A 62-year-old Italian male consulted our department complaining symptoms such as dysphagia particularly for solid foods and disphonia of 4 months duration. Physical examination revealed a swelling of the right submandibular region which was elastic, soft, mobile. A TC without contrast showed a low density homogeneous mass with sharp margins in the right retropharyngeal space extending into the parapharyngeal one until to the belly of the right sternocleidomastoid muscle. The mass was the same density as fatty tissue. Within this space, the major vascular structures were displaced to laterally. A fine needle aspiration cytology (FNAC) was conclusive for the presence of “homogeneous proliferation of mature adipocytes”, compatible with lipoma. We performed tumor excision via a transcervical incision under general anesthesia. Intraoperatively, a large mass was located adjacent to the front part of the major neurovascular structures. The tumor comprised a yellow, soft, fatty mass covered with a thin fibrous capsule. Tumor extension into the parapharyngeal space was confirmed. It was easily removed without injury of any major neurovascular structures. Histopathological diagnosis was lipoma characterized by sharply demarcated with thin fibrous connective tissue and comprised of homogeneous proliferation of mature adipocytes lobulated with a fine fibrous septa. DISCUSSION Lipoma of the head and neck extending into the parapharyngeal space is extremely rare and usually progresses asymptomatially until reaching a large size. Today TC, MRI and FNAC provided early detection of these lesions. TC is useful to reveal link between the tumor and neurovascular structures and helps to suggest tumor origin by dislocation of the fat tissue and major vessels. On MRI, lipoma demonstrate homogeneous lesions with sharp margins and signal hyperintensity on T1-weighted imaging and moderate intensity on T2-weighted imaging, similar to subcutaneous fat. Management of lipoma involves surgical excision. Many approaches to these tumors have been reported. However, such as in our case, the transcervical incision is considered the most appropriate approach from many authors, for reason that is possible to obtain a wide exposure of important neurovascular structures, contained into the parapharyngeal space.