Member-only story
Lymphoplasmacytic Lymphoma Involving Nasal Sinuses
Lessons From the Friday Unknowns
Neoplastic cells are predominantly of small and intermediate size and show overt plasmacytoid differentiation. Many have nuclear pseudoinclusions (Dutcher bodies). Lymphoepithelial lesions are not detected.
![](https://miro.medium.com/v2/resize:fit:700/1*HeUix7tD8hXffeoW15EMLw.png)
![](https://miro.medium.com/v2/resize:fit:700/1*fBpt6XE8Yc_kSCEoxi-2sQ.png)
![](https://miro.medium.com/v2/resize:fit:700/1*rWM21Z2fZIeaMBJvw2obGA.png)
The neoplastic cells are positive for CD20, CD45 and PAX-5. Immunoperoxidase stains for kappa and lambda immunoglobulin light chains show monotypic lambda positivity of neoplastic cells, which are present in a background of polytypic plasma cell cells.
Neoplastic cells are non-immunoreactive for CD3, CD5, CD10, BCL-6 and cyclin D1. A subset of plasmacytoid cells appears to show weakly positive expression of CD43. Plasma cells that are admixed with neoplastic cells show positive immunostaining for CD138.
![](https://miro.medium.com/v2/resize:fit:700/1*c4tNa65dJxsgtXyT5HqMww.png)