Detection of clonality with kappa and lambda immunohistochemical analysis in cutaneous plasmacytomas.
BACKGROUND
Cutaneous plasmacytomas rarely occur in the setting of multiple myeloma. However, since poorly differentiated lesions may resemble other neoplasms, such as carcinoma, melanoma, and lymphoma, the diagnosis of cutaneous plasmacytoma may be difficult.


OBJECTIVE
To demonstrate clonality using kappa and lambda immunohistochemical analysis in cutaneous plasmacytomas and to ascertain whether or not interpretation is hindered by background staining.


METHODS
Pathology reports of all patients with the diagnosis of multiple myeloma were reviewed. Twelve patients had cutaneous lesions diagnosed as plasmacytoma, and these lesions were analyzed for light chain restriction with kappa and lambda immunohistochemical analysis.


RESULTS
In most cases (11 of 12), monoclonality was demonstrated. In the remaining case, monoclonality could not be established because most cells did not stain for either kappa or lambda.


CONCLUSIONS
Light chain restriction can be demonstrated in most multiple myeloma-related cutaneous plasmacytomas, establishing the neoplastic nature of the infiltrate.
Bayer-Garner
Ilene B
IB
Department of Pathology, Marshfield Clinic, Marshfield, Wis 54449, USA. garner.ilene@marshfieldclinic.org
Prieto
Victor G
VG
Smoller
Bruce R
BR
D002999:Clone Cells; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000032:analysis*; D007146:Immunoglobulin lambda-Chains / Q000032:analysis*; D007150:Immunohistochemistry; D009101:Multiple Myeloma / Q000473:pathology; D010954:Plasmacytoma / Q000175:diagnosis* / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology
D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains