|Year : 2018 | Volume
| Issue : 1 | Page : 15-17
Parapharyngeal space lipoma mimicking cystic hygroma
Aditya Pratap Singh, Ramesh Tanger, Arun Kumar Gupta
Department of Pediatric Surgery, SMS Medical College, Jaipur, Rajasthan, India
|Date of Submission||13-Nov-2016|
|Date of Decision||13-May-2019|
|Date of Acceptance||18-Dec-2019|
|Date of Web Publication||20-Jan-2020|
Dr. Aditya Pratap Singh
Near the Mali Hostel, Main Bali Road, Falna, Pali, Rajasthan
Source of Support: None, Conflict of Interest: None
Parapharyngeal space (PPS) tumors constitute only 0.5%–0.8% of all tumors of which lipoma is the rarest. In general, lipoma is found just beneath the subcutaneous tissues. Here, we present a case of a 2-year-old female child with lipoma of the right PPS extending into the neck mimicking cystic hygroma on presentation.
Keywords: Lipomas, parapharyngeal space tumors, soft-tissue tumor, tumors in children
|How to cite this article:|
Singh AP, Tanger R, Gupta AK. Parapharyngeal space lipoma mimicking cystic hygroma. Niger J Surg Sci 2018;28:15-7
| Introduction|| |
Lipoma is a benign neoplasm of adipose cells and constitutes 16% of all the soft-tissue neoplasms. It is mesenchymal in origin and rarely found in deep areas. The presence of lipoma in the head and neck is rare and contributes to 0.5% of all parapharyngeal space (PPS) tumors. Only 10 cases have been reported so far of lipoma in PPS.,,,,,
| Case Report|| |
A 2-year-old girl presented with a 4-month history of slowly progressive, painless swelling of the right side of the neck. There were no associated symptoms. The patient had visited another hospital-based facility where she was diagnosed to have cystic hygroma and was referred to our center. On examination, a soft, fluctuant, mobile, painless, nontender mass was observed on the right side of the neck. The mass was extending superiorly to the submandibular region and inferiorly to the mid of the neck having approximately 4 cm × 5 cm size. The overlying skin was normal without any signs of discoloration or abnormal vascularization. Facial nerve function was intact.
Initial differential diagnosis on the basis of clinical appearance and examination consisted of cystic hygroma and lipoma. The ultrasound revealed a well-defined, 4 cm × 6 cm isoechoic mass seen between the right parotid and submandibular glands suggestive of lipoma or epidermoid cyst.
The patient underwent magnetic resonance imaging (MRI) which suggested a well-defined altered signal intensity lesion in the anterior triangle of the neck on the right side. It measured approximately 30 mm × 26 mm × 46 mm likely to represent lipoma. The lesion was superficial to the sternocleidomastoid muscle. Superiorly, the lesion was extended to the parotid gland and closely abutting on it with a maintained fat plane. It was extended medially to the parapharyngeal region. The lesion appeared hyperintense on both T1- and T2-weighted images with signal suppression on short tau inversion recovery images [Figure 1] and [Figure 2]. Few thin internal septations were noted within the lesion. The mass was excised under general anesthesia through an extended submandibular incision below the mandible [Figures 3], and the wound was closed primarily. The postoperative recovery was good, and the sutures were removed on postoperative day 7. Overall outcome was good, and histopathological findings were consistent with lipoma.
|Figure 1: Magnetic resonance coronal images of the parapharyngeal space lipoma|
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|Figure 2: Magnetic resonance saggital image of the parapharyngeal space lipoma|
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| Discussion|| |
Lipoma is a benign tumor composed of mature white adipocytes and is the most common mesenchymal neoplasms in adults and rarest in children. It is known to preferentially affect the following sites: Anterior neck, infratemporal fossa, oral cavity, hypopharynx, larynx, parotid gland, and PPS.,
Singh et al. reported a female preponderance in the Asian subcontinent with highest in patients from 20 to 40 years. However, no case was reported in children <10 years of age. Other reports also suggested that lipomas commonly affect adults in 40–60 years of age,, but the index case was a 2-year-old female child.
Lipoma size remains small but may reach a huge size and weight over the years. Small lipomas could be asymptomatic while large may be symptomatic due to compression of surrounding structure as well have cosmetic concern. Its different variants include angiolipomas, neomorphic lipomas, spindle cell lipomas, and adenolipomas. Liposarcoma which is the malignant variant is difficult to differentiate from a simple lipoma on the basis of physical examination and radiology. Therefore, every lesion suspected to be lipoma with >5 cm should raise a suspicion of malignancy, and biopsy should be done to exclude liposarcoma. Liposarcoma contributes to 15%–20% of head-and-neck sarcomas with only 10%–20% affecting children.
In the PPS, it can cause oropharyngeal swelling, odynophagia, difficulty in breathing, cervical swelling, neurological deficit like hoarseness, slurring of speech, weakness of the shoulder, blurring of vision, and multiple cranial nerve palsies. Our case was asymptomatic. Computed tomography (CT) scan, MRI, and fine-needle aspiration cytology fine needle aspiration cytology (FNAC) are diagnostic tools for lipomas.
The area is tricky and approach is based on location, size, vascularity, and malignant potential though rare. Typically, these tumors are well circumscribed, encapsulated (often by a fibrous shell), tend to be smooth or lobulated, easy to remove, and rarely reoccur.
CT scan proved to be 88% accurate in helping to clinch a concurrent diagnosis. Comprised mature adipose tissue, a classic lipoma has CT and MRI signal intensity characteristics similar to those of subcutaneous fat. The deep lipomas are variable in shape likely because they adopt shape according to the surrounding structures.
MRI provides better tumor delineation because it has superior soft-tissue contrast resolution and clear definition of the location and longitudinal extent of the mass (giant infiltrating). It is particularly important in the orofacial region where the margins of lipoma are ill-defined because these lesions are often surrounded by normal fat tissue and have a very thin capsule.
A review of the literature revealed that the index case is unique because of its gigantic size in a 2-year-old girl, asymptomatic, and the site of involvement at presentation. The appearance was deceiving mimicking cystic hygroma which was the initial diagnosis. After the ultrasound and MRI, differential diagnosis of lipoma and liposarcoma was made. Postoperatively, the lesion was sent for histopathology which confirmed the diagnosis of benign lipoma.
| Conclusion|| |
Lipoma is a rare lesion affecting the PPS in children. Though benign, it may attain a huge size and may or may not cause symptoms. Approaching PPS lipoma is tricky, especially in children, and CT and MRI are very helpful in making the final diagnosis. Since lipoma and liposarcoma are clinically similar, it is important to make a final diagnosis either on the basis of fine-needle assisted cytology (FNAC) or excisional biopsy. Treatment is surgical removal of the complete lesion. Recurrences are rare.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to b'e reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]