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+A 18-year-old man presented with a history of a palpable lump in the presternal area, which was found incidentally after weight reduction.
+The patient had no other relevant medical or trauma history.
+On physical examination, the lesion was found to be a nonmovable, firm mass with no tenderness or associated skin changes, detected at the midline position over the sternum (at the manubrium level).
+There was no visible fistulous opening or discharge from the lesion.
+On ultrasonography, we detected a well-circumscribed, oval, anechoic mass, with posterior acoustic enhancement, that measured about 3.3 × 1.7 × 3.1 cm, and was located in the subcutaneous fat layer over the sternum.
+In the dependent portion of the mass was an internal, well-circumscribed, heterogeneously hypoechoic, egg-shaped lesion (Fig.1A and B) showing a movement according to patient movement.
+The mass could be compressed using the linear transducer (Fig.2A and B).
+A color Doppler study showed no vascularity within the cystic mass or the internal hypoechoic lesion (Fig.1C).
+Surgical excision of the mass was performed without postoperative complications.
+Grossly, the excised mass was a well-defined, ovoid, cystic mass gray-tan in color.
+On section, it was found to be a unilocular cyst filled with whitish mucous material.
+Microscopically, the mass was lined with ciliated pseudostratified columnar epithelium suggestive of respiratory type-mucosa (Fig.3).
+There was nonspecific collagenous fibrosis around the cyst.
+The differential diagnosis of subcutaneous cyst included epidermal inclusion cyst, thyroglossal duct cyst, branchial cleft cyst, and dermoid cyst.
+There was no histological evidence of squamous epithelium, keratin, thyroid tissue, or skin appendage in the cystic wall of the present case.
+The mass was diagnosed as a bronchogenic cyst.