OBJECTIVE: To report a case of unilateral plasmocytoma of the tonsil and compare tonsillectomy with tonsillar biopsy for initial management. CASE REPORT: An 18-year-old Caucasian female presented herself to the otorhinolaryngology emergency clinic with fever, lymphadenopathy, and sore throat for the past 3 days. There was no personal or family history of any disease. Physical examination revealed purulent exudate over both tonsils, which showed significant asymmetry in size with the right tonsil bigger than its counterpart. The patient was advised to return after completing the course of prescribed antibiotics; examination on follow-up showed no change in tonsillar size, and there was no lymphadenopathy. Therefore, the right tonsil was biopsied for histopathological examination, which showed plasmocytoma, a rare tumor characterized by monoclonal proliferation of plasma cells. Multiple myeloma was ruled out with laboratory tests and radiological examination. Most patients do not have true asymmetry of the tonsils, especially in the absence of other symptoms such as weight loss and cervical lymphadenopathy. The majority of cases of apparent asymmetry are caused by a distortion of the local anatomy that makes one tonsil appear larger than the other. There is no consensus about the desirability of biopsy over tonsillectomy in such situations, because non-representative biopsies can be misleading. On the other hand, there is concern about the failure to achieve tumor-free surgical margins after tonsillectomy, especially when there is a suspicion of malignant disease. CONCLUSION: There is no consensus in the literature about the best course of action in cases of tonsillar asymmetry, but the majority of the articles support the choice of tonsillectomy.