[Solitary plasmacytoma: a clinicopathologic and immunophenotypic analysis of 43 cases].
OBJECTIVE
To investigate the clinicopathologic and immunophenotypic features of solitary plasmacytoma and discuss the diagnosis and differential diagnosis of the tumor.


METHODS
Clinicopathological study and follow up study were made on 43 cases of solitary plasmacytoma, including 24 cases of extramedullary plasmacytoma (EMP) and 19 cases of solitary plasmacytoma of bone (SPB). Immunohistochemical staining was performed by SP method using antibodies CD20, CD79a, PC, Ig kappa, Ig lamda, IgA, IgD, IgE, IgG and IgM.


RESULTS
Rgarding EMP, the male/female ratio is 2.5 to 1, the age ranges from 3 to 70 years (mean 49). Clinically, the neoplasms of 22 cases were located in nasal cavity or nasosinus, 2 cases were located in lung and tonsil respectively. Rgarding SPB, the male/female ratio is 1:1, the age ranges from 36 to 72 years (mean 53). Clinically, the neoplasms of 8 cases were located in vertebrae, 3 cases in pelvis, 6 cases in clavicle, rib and femur respectively, 2 case in radius and tibia respectively. Histopathological examination revealed tumor cells diffuse infiltration with necrosis and ulceration; the well-differentiated tumor cells were similar to the normal plasmacyte in shape; the poorly-differentiated tumor resembled centroblasts; there were a few interstitial tissues with plenty of vessels or formation of blood lakes; and there was deposition of amyloid materials. Immunophenotypic analysis showed that all tumor cells were positive for CD79a and negative for CD20; that plasma cell marker (VS38C) was expressed in 41 cases; that light chain restriction was detected in all 43 cases( 31 for lamda and 12 for kappa), and that heavy chain expression was detected in 39 for IgG, 1 for IgA, 2 for both IgG and IgM, and 1 for IgA/IgG.


CONCLUSIONS
The special histopathology in this group of solitary plasmacytomas is presented. The well-differentiated tumors should be distinguished from reactive plasmacytosis and MALT. And, when poorly-differentiated solitary plasmacytomas were tentatively diagnosed, large cell lymphoma, melanoma and poorly differentiated carcinoma should be considered in differential diagnosis.
Yang
Fan
F
Department of Pathology, West China Hospital, Sichuan University, Chengdu 610041, China.
Liu
Wei-ping
WP
Jiang
Li-li
LL
Li
Feng-yuan
FY
Liao
Dian-ying
DY
Li
Gan-di
GD
D000293:Adolescent; D000328:Adult; D000368:Aged; D018951:Antigens, CD20 / Q000032:analysis*; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology; D051925:CD79 Antigens / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis*; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D010954:Plasmacytoma / Q000378:metabolism / Q000473:pathology*
D018951:Antigens, CD20; D051925:CD79 Antigens; D007136:Immunoglobulins