Amelanotic Malignant Melanoma of Unknown Primary Origin Metastasizing to the Bone Marrow: A Case Report and Review of the Literature

作者：Suzuki Tomotaka^*; Kusumoto Shigeru; Iida Shinsuke; Tada Toyohiro; Mori Fumiko

来源：Internal Medicine, 2014, 53(4): 325-328.

DOI：10.2169/internalmedicine.53.1412

• malignant melanoma
• unknown primary origin
• bone marrow
• amelanotic
• CD56

We herein describe the case of a 77-year-old Japanese man who presented with progressive thrombocytopenia. No lymphadenopathies, bone lesions, hepatosplenomegaly or masses within any internal organs were detectable. Bone marrow smears revealed diffuse infiltration of large atypical cells morphologically resembling mature lymphoid neoplasms. A flow cytometric analysis showed that the tumor cells strongly expressed CD56 without myeloid or lymphoid antigens, suggesting that they were non-hematologic in origin. Ultimately, amelanotic malignant melanoma of unknown primary origin was diagnosed based on positive immunostaining for S100 proteins, HMB-45 and Melan-A. This case illustrates the usefulness of flow cytometric analyses for making such diagnoses. We also review the available literature on similar cases.

• 出版日期2014