Immunophenotyping of mature T/NK cell neoplasm presenting as leukemia.

Introduction : Mature T/NK cell lymphomas (MTNKL) presenting as leukemia are rare and show considerable overlapping of clinical, morphological and immunophenotypic features. AIM: Critical analysis of the morphology and immunophenotypic profile of MTNKL. Materials and Methods : We reviewed 380 consecutive cases of mature lymphoid neoplasm that presented as leukemia and were diagnosed on morphology and immunophenotyping of bone marrow and/or peripheral blood samples. Results : Peripheral blood and bone marrow involvement was seen in all cases. MTNKL constituted 4% (nine cases) of all mature lymphoid neoplasms presenting as leukemia. It included four cases of T-large granular leukemia (T-LGL), two of T-cell prolymphocytic leukemia small cell variant (T-PLL), two of adult T-cell leukemia/lymphoma (ATLL) and one of primary cutaneous gamma delta T-cell lymphoma (PCGDTCL). T-LGL revealed CD4-/CD8+ phenotype in three, and CD4+/CD8+ phenotype in one case. CD56 was absent in all the cases of T-LGL. One case of T- PLL small cell variant showed CD4+/CD8- phenotype, while the other revealed CD4-/CD8+ phenotype. Both cases of ATLL showed CD4+/CD8+/CD25+ phenotype. The single case of PCGDTCL showed CD4-/CD8- phenotype pattern. CD3 and CD5 were expressed in all MTNKL. CD7 was absent in three cases of T-LGL. TCRα/β was performed in three cases of T-LGL and was positive in all. TCRα/β was also seen in both the cases of T-PLL small variant. However, TCRα/β was seen in the single case of PCGDTCL. Conclusion : Mature nodal T/NK cell neoplasms are rare and MTNKL presenting as leukemia are even rarer. There is an overlap between the immunophenotypic profiles of different MTNKL subtypes and elaborate T/NK cell panels are required for their evaluation.

CD4+CD56+Lineage Negative Hematopoietic Neoplasm: So Called Blastic NK Cell Lymphoma

Blastic natural killer (NK) cell lymphoma is a rare neoplasm characterized by blastoid tumor cells expressing CD4 and CD56, with predominant skin involvement. Although this tumor has been regarded as a neoplasm related to NK cell, recent studies suggested that it is derived from plasmacytoid dendritic cells, but not from NK cell. Herein we report 4 cases of CD4+CD56+ lineage marker- blastic NK cell lymphomas with a review of literatures. The patients were 3 men and one woman. Three of them were young (17, 18, and 22 yr old). Three patients had skin lesions, at initial presentation in two patients and during the course of disease in other patient. Histologically, tumors consisted of monotonous medium to large blastoid cells showing no necrosis, angiocentric growth or epidermotrophism. All four tumors were CD4+ and CD56+. Three expressed CD68 antigen. Lineage specific markers for B- and T cell were negative. All tumors did not express myeloperoxidase. T-cell receptor gene rearrangement, EBV, CD13 and CD33 were negative. In one patient, tumor cells arranged in Homer-Wright type pseudorosette and expressed terminal deoxynucleotidyl transferase(TdT). Despite the standard lymphoma chemotherapy, the tumors, except one lost during follow-up, progressed and relapsed. The patients died 8-60 months after diagnosis.

Intravascular lymphomatosis of the T cell type presenting as interstitial lung disease--a case report

Intravascular lymphomatosis (IL) is a rare and generally fatal disease characterized by proliferation of large lymphoma cells almost exclusively within the lumen of small blood vessels. The skin and central nervous systems are typically affected, but involvement of other organs, such as lung, has been described. Predominant lung involvement without cutaneous and neurologic manifestation is very rare and difficult to diagnose. Originally considered as an endothelial disorder, IL has recently been reclassified as lymphoma. Most of the cases reported are of B cell lineage with a few cases of T cell type. We describe a case of the T-cell type IL manifested clinically as an interstitial lung disease without involvement of skin and central nervous systems. Immunohistochemical studies showed the T-cell nature of the neoplastic cells in open lung biopsy sample.