Acinic cell carcinoma with primary presentation in an intraparotid lymph node.

A rare case of a poorly-differentiated acinic cell carcinoma with primary presentation in a hyperplastic intraparotid lymph node, is reported. As the tumour mainly consisted of ductular and undifferentiated cells growing in solid cords, diagnosis was rendered difficult. Typical acinic cells were only rarely observed. In the multiple sections reviewed a single tumour nodulus occurred in salivary gland tissue outside the lymph node capsule. The possibility of a microscopic clinically occult primary acinic cell carcinoma that metastasized and presented primarily in an intraparotid lymph node, is mentioned. A multifocal origin in salivary tissue within and outside the intraglandular lymph node is another assumption, which is discussed. Differential diagnoses are mentioned and results of immuno- and histochemical studies are reported.