Reactive Follicular & Paracortical Immunoblastic Hyperplasia in Tonsils

Siba El Hussein, MD
2 min readJul 18, 2022

Lessons From the Friday Unknowns

The patient presented with severe throat pain, cold-like symptoms and headache. COVID and influenza testing was negative.

The tonsils show reactive follicular hyperplasia and expansion of the interfollicular regions by plasma cells and immunoblasts. In some areas the immunoblasts form clusters and sheets. Surrounding the tonsils are areas of acute inflammation, necrosis and hemorrhage that are particularly prominent surrounding the right tonsil.

The follicles are composed mostly of B cells positive for CD20 and PAX-5. There are many interfollicular T cells positive for CD3 and CD5. T cells are a mixture of CD4 positive and CD8 positive cells.

The antibody specific for CD30 highlights many larger cells within the tonsils consistent with immunoblasts. These immunoblasts are negative for CD15, and many are positive for CD20 and PAX-5. Plasma cells are positive for CD138. The results for ALK and pankeratin are noncontributory.

The antibody specific for Ki-67 shows a very high proliferation rate within follicles and a lesser but brisk proliferation rate within the interfollicular regions. No evidence of Epstein–Barr virus encoded RNA (EBER) is identified.


In summary, both tonsils show acute tonsillitis with necrosis associated with reactive lymphoid hyperplasia and peritonsillar acute inflammation which is prominent surrounding the right tonsil. There is no morphologic evidence of lymphoma.

Link to digital slides: | Case 5



Siba El Hussein, MD

Hematopathology | Cytopathology | Molecular pathology | Digital pathology | Data science | Machine learning