In Situ Follicular B-Cell Neoplasm Presenting as Miliary Facial Papules: A Unique Clinical Presentation and Spontaneous Regression.

In situ follicular B-cell neoplasm (ISFN) is a variant of follicular lymphoma, presenting as an incidental histologic finding in lymph node biopsy or excisional specimens. ISFN presents with a B-cell population that strongly expresses BCL2 and CD10 within the germinal centers of a lymph node or extranodal site. Genetic analysis shows t(14;18) translocation. Herein, we report a case of ISFN presenting as military and agminated facial papules in a young woman, which resolved spontaneously in the postpartum period. To our knowledge, this is the only report of a cutaneous site of involvement of this rare entity.