Primary uterine lymphoma: The Yokohama Cooperative Study Group for Hematology (YACHT) study.

AIM: Primary malignant lymphomas arising from the female genital tract are very rare, with an incidence rate of 0.5%. Because of its rarity, its clinical characteristics, prognosis and optimal treatment are still unclear. Here, we retrospectively evaluated female patients with uterine lymphoma.

METHODS: Between January 2000 and October 2016, 4362 patients were newly diagnosed with malignant lymphoma by the participating institutions of YACHT. Among these 4362 patients, we retrospectively evaluated 14 adult patients with primary uterine lymphoma.

RESULTS: The median follow up time was 41 months. The median age at diagnosis was 68 years. Of 14 patients, 10 (72%) were diagnosed with diffuse large B-cell lymphoma. Seven patients presented with vaginal bleeding and three with abdominal pain. Eleven patients (79%) had advanced stages at diagnosis. Three patients (21%) had ovarian involvement and 2 (14%) had vaginal involvement. Induction chemotherapy regimens were R-CHOP in seven patients (50%), CHOP in three (21%) and other regimens in four (29%). Among 14 patients, 12 patients (86%) achieved a complete response and 2 (14%) experienced disease progression. Three patients (21%) showed relapse. Five patients (36%) died because of malignant lymphoma. The 3-year overall survival rate was 57.9%. Soluble interleukin-2 receptor levels > 5000 U/mL, anemia, a bulky mass and the presence of > 1 extranodal sites, B symptom at diagnosis were associated with a poor prognosis.

CONCLUSION: Female genital lymphoma is very rare, and further study of more cases is warranted.