Signet ring cell lymphoma: a rare variant of follicular lymphoma.

A case of signet ring cell lymphoma, the eighth in published reports is recorded. This rare tumour is a variant of follicular lymphoma which may be mistaken for metastatic carcinoma. The case has been studied by light microscopy, immunohistochemistry and electron microscopy and confirms that this sub-group has rather uniform characteristics. Observations on the possible origins of the vacuoles are presented.