A 66-year-old woman with multiple cutaneous and nodal relapses of marginal zone lymphoma presented with a painful oral ulceration. A biopsy showed an ulcerated squamous mucosa (panel A; hematoxylin and eosin stain, 2× objective [20× total magnification]) with a polymorphous inflammatory infiltrate composed of small lymphocytes, histiocytes, eosinophils, and scattered large atypical lymphoid cells with vesicular chromatin and prominent nucleoli (panel B; hematoxylin and eosin stain, 100× objective [1000× total magnification]), which were positive for CD30 and subset positive for T-cell antigens CD3 and CD2 (panels C-E; 100× objective [1000× total magnification]; red arrows, positive cells; green arrows, negative cells). An in situ hybridization for Epstein-Barr virus-associated RNA was negative. The polymerase chain reaction-based T-cell receptor γ gene rearrangement studies were polyclonal (panel F). A diagnosis of traumatic ulcerative granuloma with stromal eosinophilia (TUGSE) was made.TUSGE is a unique, benign, self-limiting oral lesion primarily caused by mucosal trauma on the lateral tongue, which clinically and morphologically mimics lymphoma because of its rapid development and delayed healing, and the presence of large atypical CD30 + T cells associated with clonal T-cell receptor gene rearrangements in ∼25% of cases. It is essential to recognize this entity, especially in immunocompromised patients with a prior history of malignancy, as despite a 12% to 30% local recurrence rate, these lesions do not progress to a systemic lymphoproliferative disorder and undergo spontaneous regression with no additional therapy.