Intrasinusoidal HHV8-EBV-Positive Large B-Cell Lymphoma With Features of Germinotropic Lymphoproliferative Disorder

Germinotropic lymphoproliferative disorder (GLPD) is a poorly characterized lymphoproliferative entity, recently included in the World Health Organization classification of hematolymphoid neoplasms. The histological pattern of this disease comprises monotypic plasmablasts that involve the germinal centers of the lymphoid follicles (germinotrophism), forming confluent aggregates positive for both human herpes virus type 8 (HHV8) and Epstein-Barr virus. Currently, after 17 years of its first description, only 18 cases have been reported. In this article, we describe a case of a GLPD presenting in an immunocompetent 79-year-old woman with localized axillary lymphadenopathy, showing a prominent sinusoidal growth pattern, with no evidence of germinotrophism or extrasinusoidal spread. Stinking pleomorphism in tumor cells was also noted. An extension study has not revealed involvement of other groups of lymph nodes or extralymphoid sites. The patient is alive and has shown no relapse after 8 years follow-up (the longest follow-up reported period for this entity). This previously unrecognized pure sinusoidal growth pattern along with the striking pleomorphism in neoplastic cells closely mimics the appearance of an anaplastic large cell lymphoma. GLPD is not usually considered in such a setting, but it should be included in the differential diagnosis of sinusoidal proliferations. Our findings contribute to the expansion of the morphological spectrum of HHV8-associated lymphoproliferative lesions and aids in the characterization of the very infrequent GLPD entity.