역형성 골수종은 이형성 골수종, 침습적 골수종 혹은 골수아세포육종 등으로 알려진 질환으로 골수종의 전형적인 형태를 띄지않아 진단이 늦어지는 경우가 있다. 본 저자들은 악성 세포의 비특이적인 형태로 인해 초기진단에 어려움이 있었던 45세 남자 환자가 면역표현형 검사상 CD38, CD56, HLA-DR 등에 양성을 보였고 혈청 단백전기영동에서 단클론성 peak를 나타내어 역형성 골수종으로 진단된 예를 경험하였다. 고식적인 화학 치료에도 불구하고 진단 후 7개월여만에 폐침윤과 패혈증으로 악화되어 사망한예를 문헌 고찰과 함께 보고하는 바이다.

Anaplastic myeloma has various synonyms such as dysplastic myeloma, aggressitve phase myeloma, or immunoblastic sarcoma. This is known to be an extremely aggressive subentity of plasma cell myeloma, and the diagnosis can usually be delayed because of the lack of the typical morphologic characteristics of myeloma. We describe here a 45-year-old man with anaplastic myeloma, whom we had difficulties with in initial diagnostic workup. The patient was admitted to the hospital due to gum bleeding for 2 weeks. A few abnormal cells were found in the peripheral blood. In bone marrow aspiration smears, the normal hematopoietic cells were replaced by numerous anaplastic cells. An immunophenotype study showed only a dim expression of CD56 antigen, while other routine surface antigens as well as CD45 were all negative. Additional studies showed a moderate positivity of CD38 and cytoplasmic lambda light chain. Serum immunoelectrophoresis confirmed monoclonal lamda light chain production, which led to the diagnosis of anaplastic myeloma. Because the morphologic feature is confused with other lymphoproliferative disorders, the diagnosis of anaplastic myeloma could be delayed unless a high degree of suspicion is made. Cytoplasmic light chains as well as CD56 will be helpful in initial immunophenotyping workup when the neoplastic cells show anaplastic features. (Korean J Lab Med 2004; 24: 203-6)

Anaplastic myeloma has various synonyms such as dysplastic myeloma, aggressitve phase myeloma, or immunoblastic sarcoma. This is known to be an extremely aggressive subentity of plasma cell myeloma, and the diagnosis can usually be delayed because of the lack of the typical morphologic characteristics of myeloma. We describe here a 45-year-old man with anaplastic myeloma, whom we had difficulties with in initial diagnostic workup. The patient was admitted to the hospital due to gum bleeding for 2 weeks. A few abnormal cells were found in the peripheral blood. In bone marrow aspiration smears, the normal hematopoietic cells were replaced by numerous anaplastic cells. An immunophenotype study showed only a dim expression of CD56 antigen, while other routine surface antigens as well as CD45 were all negative. Additional studies showed a moderate positivity of CD38 and cytoplasmic lambda light chain. Serum immunoelectrophoresis confirmed monoclonal lamda light chain production, which led to the diagnosis of anaplastic myeloma. Because the morphologic feature is confused with other lymphoproliferative disorders, the diagnosis of anaplastic myeloma could be delayed unless a high degree of suspicion is made. Cytoplasmic light chains as well as CD56 will be helpful in initial immunophenotyping workup when the neoplastic cells show anaplastic features. (Korean J Lab Med 2004; 24: 203-6)

Anaplastic myeloma, Complex chromosomal abnormalities, CD56, Immunophe-notyping