most plasma cell neoplasms form multiple tumors in the bone and cause a generalized marrow plasmacytosis . these neoplasms rarely present as identified most frequently in the upper respiratory tract and have also been recorded in other organs , including lymph nodes and spleen , skin , gastrointestinal tract , and thyroid . on the other hand , extramedullary involvement in the course of multiple myeloma , in the form of macroscopic and or microscopic plasma cell infiltrates , is observed in approximately 2/3 of the patients with myeloma and who are subject to autopsy . the localization can be limited to the paraskeletal areas or involve distant organs and tissue - the spleen , liver , lymph nodes and kidney , in particular . in addition , most of them were detected at autopsy and symptomatic plasma cell neoplasms of the testis were only a few . kapadia detected the presence of microscopic infiltration of extraosseous tissues in 67% of patients with multiple myeloma at autopsy and testicular involvement appeared in only 6 cases . primary testicular plasmacytoma is even more rare ; corwin reviewed 288 cases with solitary plasmacytoma involving various organs . the prognosis of plasma cell neoplasm invading extramedullary soft tissues , solitary or otherwise , is poor . we therefore report a patient with multiple myeloma , presenting as a testicular mass , who expired only 6 months after diagnosis in spite of chemotherapy . a 49-year old man was admitted to our hospital because of painless swelling of both testes and multiple bone pain . the enlargement of the right testis progressed slowly and , a few weeks later , the left testis was enlarged also . on admission his heart beat was regular and no murmur was heard . on abdominal palpation , liver , spleen or kidney were not palpable . both testes were nearly the same in size and were palpable as nontender , hard , movable masses . the size of the right and left testes were about 10 cm15 cm and 10 cm12 cm in diameter , respectively . laboratory findings were as follows ; complete blood counts were hemoglobin 9.5 gm / dl , hematocrit 28% , leukocyte 14,000/mm and platelet 140,000/mm . blood chemistry tests showed ca 11.7 mg / dl , p 6.4 mg / dl , total protein 9.5 g / dl , albumin 2.9 g / dl , ldh 509 iu / i , bun 55 mg / dl , creatinine 7.1 mg / dl , igg 3,460 mg / dl , igm 64 mg / dl , iga 43 mg / dl , igd 1.1 mg / dl . he had proteinuria ( 5,905 mg/24 hours ) and creatinine clearance was measured as 9 ml / min . serum protein electrophoresis showed m - peak in -region and m - component was measured as 43.4% . testicular needle biopsy showed diffuse infiltration of atypical large lymphoid cells with feature of poorly differentiated plasma cell nature between seminiferous tubules and inside of them as well ( fig . 1 ) . immunohistochemical studies revealed positivity for l26 ( cd20 ) and ig k predominance on infiltrating neoplastic plasmacytoid cells ( fig . after the 2nd cycle of treatment , the testicular enlargement was not decreased and multiple bone pain was aggravated . after that , he was treated with combination chemotherapy of vincristine , adriamycin and dexamethasone . one month later , however , numerous soft tissue nodules newly appeared on the left forearm , both lower legs , and chest wall . somewhat later , follow - up chest x - ray showed multiple , variable sized round opacity in both whole lung fields with pleural effusion . the patient had a rapidly progressive downhill course and died 6 months after initial diagnosis . the reported incidence of extramedullary lesions in multiple myeloma ranges from 11 to 73% , with the liver , spleen , lymph nodes , kidney and lung being the most frequently involved organs . the incidence of testicular involvement in patients with multiple myeloma is rare and it has been reported to between 1 and 3 percent . however , levin and mostofi found only 7 cases of surgically resected plasmacytomas in approximately 6000 cases ( 0.1% ) of testicular and peritesticular primary and secondary tumors on file in the american testicular tumor registry . the diagnosis of testicular tumor must be made taking into consideration the classic morphological and immunohistochemical aspects ; these are first obtained by not very aggressive techniques , such as fine needle aspiration , which will reveal the plasmocytic and malignant nature of the cells . the appearance of extraosseous localization in the course of multiple myeloma usually means poor prognosis , expressing an accelleration of the malignant process . this is the case of testicular plasmacytoma , characterized by an average survival of 34 months . typically , an insensitivity to chemotherapy is observed . the extreme is the  terminal aggressive phase  of myeloma and it is associated with high fever of unknown cause , appearance of rapidly spreading extramedullary tumor masses , reduction of the monoclonal component , no response to chemotherapy and a rapidly fatal course , ultimately . because testicular involvement in multiple myeloma is rare , there is no uniformity in the choice of treatment yet . although the combined treatment of radiotherapy and chemotherapy has produced acceptable results in one report , it may not well be established yet and further study will be required .
primary testicular plasmacytoma is extremly rare and only a few cases have been reported15 ) . 
 testicular involvement in the course of multiple myeloma is just as rare and it implies a poor prognosis , expressing an acceleration of the malignant process69).we present the case of a patient with multiple myeloma presenting as a testicular mass . 
 the literature is reviewed and testicular involvement in plasma cell neoplasms is discussed .