IHC Immunostains:
Diagnosis:
Hyaline vascular Castleman disease
Indolent T-lymphoblastic proliferation (iT-LBP)
Diagnostic features of iT-LBP:
(1) confluent groups of TdT+ T cells in a biopsy specimen, (2) relative preservation of surrounding normal lymphoid architecture, (3) TdT+ T cells without morphologic atypia, (4) absence of thymic epithelium, (5) nonclonal TdT+ T cells, (6) immunophenotype of developmentally normal immature thymic T cells, and (7) clinical evidence of indolence (follow-up >6 mo without progression). Indolent T-lymphoblastic proliferation (iT-LBP) is a non-clonal benign condition of extrathymic proliferation of T-lymphoblasts with normal thymocyte phenotype. Commonly seen in coexisting conditions such as Castleman disease, follicular dendritic cell tumors, angioimmunoblastic T-cell lymphoma, myasthenia gravis, and other malignancy such as hepatocellular carcinoma, acinic cell carcinoma (ACC).
The clinical course of iT-LBP is indolent, and no therapy is usually required. A major concern is misdiagnosis as T-lymphoblastic lymphoma.
Adv Anat Pathol. 2013 May;20(3):137-40. doi: 10.1097/PAP.0b013e31828d17ec.
Hyaline vascular Castleman disease
Indolent T-lymphoblastic proliferation (iT-LBP)
Diagnostic features of iT-LBP:
(1) confluent groups of TdT+ T cells in a biopsy specimen, (2) relative preservation of surrounding normal lymphoid architecture, (3) TdT+ T cells without morphologic atypia, (4) absence of thymic epithelium, (5) nonclonal TdT+ T cells, (6) immunophenotype of developmentally normal immature thymic T cells, and (7) clinical evidence of indolence (follow-up >6 mo without progression). Indolent T-lymphoblastic proliferation (iT-LBP) is a non-clonal benign condition of extrathymic proliferation of T-lymphoblasts with normal thymocyte phenotype. Commonly seen in coexisting conditions such as Castleman disease, follicular dendritic cell tumors, angioimmunoblastic T-cell lymphoma, myasthenia gravis, and other malignancy such as hepatocellular carcinoma, acinic cell carcinoma (ACC).
The clinical course of iT-LBP is indolent, and no therapy is usually required. A major concern is misdiagnosis as T-lymphoblastic lymphoma.
Adv Anat Pathol. 2013 May;20(3):137-40. doi: 10.1097/PAP.0b013e31828d17ec.