Rationale: Thyroglossal duct cyst (TGDC), the most common midline neck mass, has several histological diagnoses other than cyst in the literature. We present the first case of thyroglossal duct lipoma.
Patient concerns: A 63-year-old woman presented with a painless soft midline neck mass for more than 3 years, which enlarged in size and caused a lump sensation during swallowing.
Diagnoses: Sonography revealed a 3.5 × 3.0 × 3.0-cm homogenous isoechoic oval lesion without an acoustic shadow beyond the thyroid glands. An ultrasound-guided biopsy revealed abundant sheets of fat cells with infiltration of some lymphocytes and histiocytes. Computed tomography revealed a 3.5 × 3.0 × 3.0-cm well-circumscribed ovoid mass with Hounsfield unit (HU) between -50 and -100 and a thyroglossal duct remnant. All these findings supported the diagnosis of thyroglossal duct lipoma.
Interventions: The patient underwent Sistrunk operation for excision of the neck tumor, and pathological examination revealed an adipose tumor surrounded by benign thyroid tissue, confirming the diagnosis of thyroglossal duct lipoma.
Outcomes: Neither postoperative complication nor recurrence was noted at the 18-month follow-up.
Lessons: This is the first case of thyroglossal duct lipoma in the literature. Our study extends the disease spectrum of thyroglossal duct mass and suggests that clinicians should consider thyroglossal duct lipoma in the differential diagnosis of a midline neck mass.