A 59-year-old man with a history of HIV presented with a 6 cm mass involving the left palatine tonsil. Biopsy of the mass showed the histologic findings seen below. Initial immunohistochemical stains including pankeratin, p63, and S100 were negative.
Additional immunohistochemical stains revealed the following immunophenotype:
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Rosalind Sharain, M.D. Fellow, Cytopathology Mayo Clinic |
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Linda Dao, M.D. Consultant, Anatomic Pathology Mayo Clinic Assistant Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine |