Collision Hodgkin lymphoma and Warthin tumour. Report of a case and review of the literature

Association between Warthin tumour (WT) and lymphoma is extremely uncommon and the latter are generally B-cell type non-Hodgkin lymphoma. We describe a case of collision of WT and Hodgkin's lymphoma (HL) of the parotid gland. A 60-year-old man complained of slow progressive swelling of the right parotid gland. The ultrasound (US) examination detected a well-defined, bilobated hypoechoic mass located in the anterior lobe of the parotid gland. A US-guided fine-needle cytology (FNC) was performed and a cytological diagnosis of WT was made. The histological sections revealed two nodules: the main one showed a classical WT and the smaller, adjacent to the WT and separated from the later by a fibrotic band, showed residual gland and lymphoid tissue with microscopic and phenotypic features of HL. This is the third report in the literature describing a collision of WT and HL, likely representing a simple coincidence rather than a possible association between the two entities.