In situ follicular lymphoma associated with nonlymphoid malignancies.

In situ follicular lymphoma (FL) is usually an incidental finding in otherwise reactive lymph node. This report describes two cases of lymph nodal in situ FL complicated by the association with nonlymphoid neoplasms. In case 1, in situ FL was discovered incidentally on a biopsy performed for an unexplained cervical lymphadenopathy 6 months after the resection of a carotid body paraganglioma. In case 2, in situ FL was detected incidentally during surgery for radical resection of prostatic carcinoma. In the lymph nodes, the in situ FL foci were characterized immunohistologically by strong coexpression of BCL2 and CD10 in the involved GCs. FISH study demonstrated BCL2 rearrangement in one of the two tested cases. These data extend the spectrum of the clinical situations that may be associated with in situ FL, but the biological and clinical significance of the association of in situ FL with nonlymphoid neoplasms deserves further investigation. Important fields of investigation should include: (1) how to approach these patients who have a risk of progression to overt lymphoma; (2) is the association of in situ FL with concurrent nonlymphoid neoplasia incidental, related to immunosuppression or to previous treatment?