Traumatic ulcerative granuloma with stromal eosinophilia (TUGSE) is an ulcerative lesion of the oral mucosa with unknown pathogenesis. A few recent case reports have demonstrated molecular evidence of T-cell clonality in TUGSE and CD30 immunoreactivity in the large atypical mononuclear cells, raising the possibility that a TUGSE subset may represent the oral counterpart of primary cutaneous CD30+ T-cell lymphoproliferative disorders. We examined the immunoreactivity for CD30 and T-cell receptor (TCR) gamma gene rearrangement in 37 TUGSE cases. Clonal TCR gene rearrangements were demonstrated in 7 (24%) of 29 cases with amplifiable DNA, and the morphologic features and CD30 immunoreactivity of these cases did not differ from those with polyclonal TCR gene rearrangements. Clinical follow-up was available for 5 of 7 TUGSE cases with clonal TCR gene rearrangement for an average period of 1.75 years after the initial biopsy or excision, and there was no evidence of local recurrence or development of systemic T-cell lymphoproliferative disorder. Without morphologic and/or clinical evidence of lymphoma, T-cell clonality and/or CD30 positivity in these lesions is not indicative of malignancy and should be interpreted with caution.