Unusual presentation of primary T-cell lymphoblastic lymphoma: description of two cases

T-cell lymphoblastic lymphoma comprises approximately 85-90% of all lymphoblastic lymphomas. It often arises as a mediastinal mass, and with bone marrow involvement. Presentation at other sites without nodal or mediastinal localization is uncommon.

We describe clinical, histologic, immunohistochemical, and molecular features of two cases of primary T-cell lymphoblastic lymphoma arising respectively in uterine corpus and testis. The tumors were composed by medium to large cells, exhibiting a diffuse pattern of growth but sometimes forming indian files or pseudo-rosettes. The neoplastic cells strongly expressed TdT and T-cell markers in both uterine corpus and testis. However, the testis case also showed aberrant expression of B-cell markers, thus molecular biology was necessary to achieve a final diagnosis. T-cell receptor gene rearrangement analysis identified a T-cell origin.

To the best of our knowledge, only one doubtful previous case of primary uterine T-cell lymphoblastic lymphoma and no previous cases of primary testicular T-cell lymphoblastic lymphoma have been reported. Due to the morphology of neoplastic cells, a challenging differential diagnosis with all the tumors belonging to the so-called small round blue cell tumor category is mandatory. In ambiguous lineage cases, molecular biology may represent an adequate tool to confirm diagnosis.

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