A 16-year-old female presents with a gradually enlarging, painless orbital swelling that has persisted for 10 years. What is the most likely diagnosis?
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Painless, slowly enlarging orbital swelling since childhood or adolescence = dermoid cyst.
Step 1: Understanding the Question:
A slow-growing, painless mass in the orbit of a young patient points toward a benign developmental origin rather than a malignancy or acute vascular tumor. Step 2: Detailed Explanation:
Dermoid Cysts: These are developmental choristomas arising from surface ectoderm trapped during suture closure.
Location: They are most commonly found at the superolateral orbital margin near the frontozygomatic suture.
Clinical Features: They present as firm, smooth, painless swellings. They grow very slowly over decades, matching the "10 years" history in the stem.
Capillary Hemangioma: These appear at birth, grow rapidly for a year, and then spontaneously regress. They would not present as a 10-year progressive mass in a 16-year-old.
Lacrimal Gland Carcinoma: This is a rapidly growing, painful, and aggressive tumor of middle-aged adults, not a decade-long painless swelling in a teen.
Osteoma: While slow-growing, these are hard, bony masses usually arising within the sinuses, not soft orbital swellings.
Step 3: Final Answer:
The age, location, and slow growth pattern are classic for an orbital Dermoid Cyst.
