Anaplastic large cell lymphomas (ALCLs) represent a subset of peripheral T-cell lymphomas (PTCLs), defined by a proliferation of large lymphoid cells, referred to as hallmark cells, with strong expression of CD30. If the Immunohistochemistry (IHC) result for ALK is positive, it corresponds to systemic ALCL. If the IHC result for ALK is negative, it can be divided into systemic ALCL (sALCL) and primary cutaneous ALCL (cALCL). We report a case of a 66 - year - old man with solitary erythematous mass in his arm who was diagnosed with ALCL as a histologic examination and was diagnosed with systemic ALCL as a radiological and nuclear medical examination. The IHC test of the patient’s tissues showed ALK negative and MUM positive lymphomas. MUM-1 is known as a marker for identification of B cell lineages. However, this case confirmed that MUM-1 could be positive in ALCL. In addition, we found through literature reviews the fact that although ALK negative sALCL and ALK negative cALCL cannot be distinguished in MUM-1, it is possible to distinguish between ALK negative sALCL and ALK negative cALCL by FISH on IRF-4, a gene expressing MUM-1.