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Clinical Problem Solving: Pathology
August 2002

Pathology Quiz Case

Author Affiliations


Arch Otolaryngol Head Neck Surg. 2002;128(8):975. doi:10.1001/archotol.128.8.975

A PREVIOUSLY healthy 16-year-old girl presented with a 1-year history of increasing right ear pain and hearing loss. Her medical history was otherwise noncontributory, and she was taking no medication. Examination of the right ear revealed a bluish mass located superiorly in the middle ear. The findings of the rest of the physical examination were normal except for the presence of generalized obesity. Computed tomographic scans revealed opacification and sclerosis involving the right mastoid air cells and middle ear cavity. Mild retraction of the eardrum was also noted. During a right tympanomastoidectomy, the mass noted on physical examination was found in the antrum. The base of the skull was intact. Surgical removal of the mass was performed. A representative hematoxylin-eosin–stained section of the mass is shown in Figure 1.

Immunohistochemical analysis of the mass revealed that its cells were immunoreactive for epithelial membrane antigen (EMA) and S100 protein. Figure 2 shows 2 high-power fields of the mass, demonstrating the expression of EMA by the tumor cells in nests and condensed around psammoma bodies. The tumor cells also demonstrated strong nuclear immunoreactivity for progesterone receptors and weak nuclear immunoreactivity for estrogen receptors. Probing with anti-Ki67 (MIB-1) revealed that very few cells (<1%) expressed this proliferation antigen.

What is your diagnosis?