Sudden appearance and spontaneous regression of diffuse large B cell lymphoma in a man with a broken arm.

An elderly, demented man with stable κ bi-clonal gammopathy of unknown significance suffered a severe displaced right humeral fracture in a fall. One week later a rapidly enlarging head, neck and axillary adenopathy first appeared, including a 2 cm tonsillar node that partially obstructed the oropharynx. A left cervical node biopsy demonstrated diffuse large B cell lymphoma with CD20+, bcl-2+, κ+, CD3-, Epstein-Barr virus negative malignant cells. During the next month lymphadenopathy regressed more than 90% in the absence of treatment with chemotherapeutic agents, radiation or glucocorticoids. Following 2 months of clinical improvement, he died of pneumonia 95 days after the injury. An autopsy demonstrated residual right hilar and mediastinal malignant lymphadenopathy. These unusual events may be related to immunosuppressive and other systemic effects of acute injury on tumour behaviour.