[Indolent T-lymphoblastic proliferation in association with localized Castleman disease: A case report].

Herein we report the case of a 41-year-old woman who presented with pelvic pain. Magnetic Resonance Imaging exhibited a single pelvic mass, measuring 50mm long axis, alongside the right iliac vessels. Histological examination of the excision specimen showed a lymphoid tumor with features of localized Castleman disease, hyaline vascular type. Moreover we identified multiple interfollicular dark clusters, composed of cells morphologically resembling cortical thymocytes. Their immunophenotype was consistent with an intermediate stage of T-cell differentiation, with the expression of CD3, CD4, CD8, TdT, CD1a, CD99, CD2, CD5, CD7 and CD10, with 40% Ki67. After integration of clinical and molecular data, the retained diagnosis was an indolent T-cell lymphoblastic proliferation associated with hyaline vascular localized Castleman disease. The clinical course confirmed the indolent nature of the proliferation, despite a late local recurrence at 7 years of the initial diagnosis, without histological modification, due to an incomplete initial resection surgery.