A Case of a Rare Cutaneous Manifestation of IgH::BCL2-Translocation Negative Splenic Follicular Lymphoma

Summary: Paraneoplastic dermatoses (PD) are rare skin conditions linked to underlying malignancies, and can appear before, during, or after a malignancy develops. We present an unusual presentation of a cutaneous manifestation of splenic follicular lymphoma. A 58-year-old female with no prior medical history presented with a rash that began on her left thigh and spread to her trunk. Imaging confirmed splenomegaly with lymphadenopathy. A punch biopsy showed a dermal perivascular lymphohistiocytic infiltrate with focal spongiosis and extravasated erythrocytes. Superficial and deep lymphocytes were primarily T-cells positive for CD3, CD4, CD8, CD5, CD30, and TCR Betaf1. Sections of the splenectomy showed atypical nodular lymphoid proliferation composed of mixed centrocytes and centroblasts (>15 per high power field). The atypical B-cell follicles showed weak expression of BCL6 and LMO2, and were negative for CD5, CD10, CD43, BCL2 and MUM1, with a high Ki-67. FISH studies revealed the presence of a BCL6 rearrangement; no IgH::BCL2 translocation was identified. NGS testing identified variants in CCND3, CD274, TET2, TNFRSF14 and CREBBP. A diagnosis of grade 3A and 3B follicular lymphoma was rendered. This was a challenging case of a splenic follicular lymphoma that highlights the diverse presentation and importance of recognizing paraneoplastic cutaneous manifestations for early detection.