USMLE® Step 1 style questions USMLE
A 63-year-old woman comes to the clinic with painless, firm, mobile mass in her left cheek. She does not take any medications. She denies fever. Physical examination is unremarkable. Parotid gland biopsy shows cystic spaces surrounded by two uniform rows of epithelial cells and lymphoid stroma with germinal centers. Which of the following is the most likely diagnosis?
Normally, the parotid gland has glandular cells that make enzymes that help to break down food, as well as tiny ducts lined by epithelial cells that carry those enzymes towards the mouth.
Warthin tumor’s other name, papillary cystadenoma lymphomatosum, is long and technical but describes the disease pretty well.
Cystadenoma refers to the fact that the ducts grow in size and fill up with serous fluid and cellular debris which forms a large cyst.
Papillary refers to the fact that the layer of epithelial cells start to fold into the duct which forms a finger-like projection, called a papilla.
Finally, lymphomatosum refers to the fact that the epithelium layer gets infiltrated by lymphocytes which organize themselves into what look like germinal centers, which is something you’d would expect to find if you looked at the cross section of a lymph node.
Looking at histology, we can see the papilla, the lymphocytes, and the cystic space where the serous fluid and cellular debris are.
Now, Warthin’s tumor isn’t malignant, meaning that it doesn’t break through the basement membrane layer of the tissue, although there is a connective tissue capsule usually forms around the growing tumor, which clearly demarcates it from the rest of the parotid gland.
Also, the parotid gland start to not function normally, since the ducts turn into cysts and normal epithelial cells stop functioning.
- "Robbins Basic Pathology" Elsevier (2017)
- "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
- "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
- "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
- "Benign Parotid Tumors" Otolaryngologic Clinics of North America (2016)