P3–010 - Testicular and Leptomeningeal Relapse as Myeloid Sarcoma in a Patient Initially Diagnosed with T Lymphoblastic Lymphoma

Abstract

Background: T lymphoblastic lymphoma (T-LBL) is a neoplasm of lymphoblasts committed to the T-cell lineage. Although the tumor cells are usually TdT-positive, occasional cases of TdT-negative and CD99-positive T-LBL have been reported. Myeloid sarcoma (MS) is a rare subtype of acute myeloid leukemia involving extramedullary anatomic sites. It may be difficult to distinguish such a rare case of T-LBL from MS. Here we report a patient who was initially diagnosed as having T-LBL and later developed testicular and leptomeningeal recurrence as MS during intensive chemoradiotherapy including central nervous system (CNS) prophylaxis.Case reportA 48-year-old man was referred to our hospital because of a supraclavicular mass. FDG-PET/CT showed increased FDG uptake in the supraclavicular and axillary lymph nodes, and a bulky mediastinal tumor. Fine needle biopsy from the mediastinal tumor was performed. Histopathologically, diffuse infiltration of medium-sized tumor cells with scant cytoplasm and dense chromatin, which was accompanied by nuclear fragmentation, was observed. Immunohistochemistry demonstrated that the tumor cells were negative for CD1a, CD3, CD8, CD20 and TdT, and positive for CD4, CD43, CD56 and CD99. Bone marrow examination revealed no evidence of the infiltration of tumor cells. He was diagnosed as having T-LBL at clinical stage II and underwent an ALL-type chemotherapy regimen. After the induction chemotherapy, he achieved partial response, and received subsequent post-remission and CNS prophylaxis therapies according to the treatment schedule. Because he noticed painless right testicular swelling, right orchiectomy was performed for diagnosis. The flow cytometric analysis of cell suspensions of the biopsied specimen revealed positivities for CD13, CD33, CD34 and MPO, and the tumor was diagnosed as MS. Cerebrospinal fluid examination showed infiltration of myeloid blasts. We started high-dose cytarabine therapy.Conclusions: We report a rare case of testicular and leptomeningeal recurrence as MS during intensive chemoradiotherapy in a patient initially diagnosed as having T-LBL. We should take the possibility of MS into consideration in cases of T-LBL having atypical features, and we strongly recommend re-biopsy to obtain an accurate diagnosis upon relapse. Background: T lymphoblastic lymphoma (T-LBL) is a neoplasm of lymphoblasts committed to the T-cell lineage. Although the tumor cells are usually TdT-positive, occasional cases of TdT-negative and CD99-positive T-LBL have been reported. Myeloid sarcoma (MS) is a rare subtype of acute myeloid leukemia involving extramedullary anatomic sites. It may be difficult to distinguish such a rare case of T-LBL from MS. Here we report a patient who was initially diagnosed as having T-LBL and later developed testicular and leptomeningeal recurrence as MS during intensive chemoradiotherapy including central nervous system (CNS) prophylaxis. Case reportA 48-year-old man was referred to our hospital because of a supraclavicular mass. FDG-PET/CT showed increased FDG uptake in the supraclavicular and axillary lymph nodes, and a bulky mediastinal tumor. Fine needle biopsy from the mediastinal tumor was performed. Histopathologically, diffuse infiltration of medium-sized tumor cells with scant cytoplasm and dense chromatin, which was accompanied by nuclear fragmentation, was observed. Immunohistochemistry demonstrated that the tumor cells were negative for CD1a, CD3, CD8, CD20 and TdT, and positive for CD4, CD43, CD56 and CD99. Bone marrow examination revealed no evidence of the infiltration of tumor cells. He was diagnosed as having T-LBL at clinical stage II and underwent an ALL-type chemotherapy regimen. After the induction chemotherapy, he achieved partial response, and received subsequent post-remission and CNS prophylaxis therapies according to the treatment schedule. Because he noticed painless right testicular swelling, right orchiectomy was performed for diagnosis. The flow cytometric analysis of cell suspensions of the biopsied specimen revealed positivities for CD13, CD33, CD34 and MPO, and the tumor was diagnosed as MS. Cerebrospinal fluid examination showed infiltration of myeloid blasts. We started high-dose cytarabine therapy. Conclusions: We report a rare case of testicular and leptomeningeal recurrence as MS during intensive chemoradiotherapy in a patient initially diagnosed as having T-LBL. We should take the possibility of MS into consideration in cases of T-LBL having atypical features, and we strongly recommend re-biopsy to obtain an accurate diagnosis upon relapse.