Answer
D. Plasmacytoma
Discussion
Tumors composed of atypical plasma cell proliferation without any association with multiple myeloma are not that uncommon.
The upper respiratory tract is one of the sites where these tumors can occur; however, they have been described in the lower respiratory tract as well.
The use of immunohistochemical stains to determine the ratio of kappa and lambda light chains may help in the diagnosis.
