Concurrent interfollicular Hodgkin's disease and metastatic breast carcinoma in lymph nodes

The clinical and pathological findings are reported concerning a 73-year-old woman with progressive metastatic carcinoma of the left breast, who developed interfollicular Hodgkin's disease within the right cervical lymph nodes. Metastatic carcinoma and Hodgkin's disease were present concurrently as a 'collision tumor' in the lymph nodes examined. To the best of the authors' knowledge, this is the first description of a collision tumor with these particular histologic components in this tissue. The factors influencing the coexistence and the order of appearance of the two pathologies in the present case remain unknown.