Anaplastic large cell lymphoma (ALCLs) are a group CD30-positive mature T-cell lymphomas, an uncommon subtype of non-Hodgkin lymphomas, characterized by diverse clinical and genetic features. Among the types of ALCL, anaplastic lymphoma kinase (ALK)-negative ALCL, though typically involves the lymph nodes, can infrequently invade other tissues. When soft tissue involvement occurs, it may mimic the clinical presentation of infectious diseases, leading to potential misdiagnosis. Therefore, a histological examination is necessary to differentiate between ALK-negative ALCL and similar phenotypes associated with infectious conditions. This paper reports a case of ALCL, initially misdiagnosed as an infection.