Cutaneous Involvement of Angioimmunoblastic T-Cell Lymphoma Masquerading as B-Cell Reactive Lymphoid Hyperplasia.

A 59-year-old woman presented with a persistent eruption manifested as multiple agminated miliary facial papules. Histopathological examination showed prominent nodular dermal lymphoid infiltrates with hyperplastic follicles that were initially interpreted as B-cell reactive lymphoid hyperplasia. Several years later, an additional biopsy showed a dense perifollicular infiltrate with reactive primary and secondary follicles. Accompanying T cells corresponded to CD3/CD4/PD1/CXCL13-positive cells and scattered Epstein-Barr virus-positive B cells were identified by in situ hybridization. A monoclonal T-cell population was demonstrated by TCRγ and TCRβ Polymerase Chain Reaction amplification, as well as a minor abnormal circulating T-cell population by flow cytometry (0.62% of the white blood cells, CD4+CD3s-CD7-). A biopsy specimen from an enlarged right supraclavicular lymph node disclosed nodal involvement by angioimmunoblastic T-cell lymphoma. The observation of B-cell dermal nodular infiltrates with well-demarcated lymphoid aggregates forming primary lymphoid follicles may lead to overlook the T-cell component in some cases of angioimmunoblastic T-cell lymphoma. In such cases, a careful assessment of the apparently minor T-cell component is important to establish a correct diagnosis.