Anti-CD5 monoclonal antibody, clone 3-287 [FITC]

Chronic lymphocytic leukemia (CLL) is one of the most common hematological neoplasms and is the most common leukemia in western industrial nations. According to the World Health Organization classification, CLL is an indolent B-cell non-Hodgkin's lymphoma (NHL). Diagnosis requires an increase of B-lymphocytes to more than 5.0 & x202f;G/l as well as detection of CD5- and CD19-positive B-lymphocytes. Symptoms can be B symptoms, fatigue or frequent infections. Therapy is only required if there are pronounced symptoms or changes in the blood count, such as a relevant drop in hemoglobin and/or platelets. The prognosis strongly depends on the individual molecular and cytogenetic risk factors. For a long time, the first-line treatment was characterized by chemotherapy in combination with CD20 antibodies. In recent years, the approval of new targeted drugs has changed the treatment landscape significantly and has led to a shift towards chemotherapy-free regimens.

The association of mediastinal germ cell tumor (GCT) and hematological malignancy is a well-documented but extremely rare phenomenon. This syndrome is characterized by the occurrence of nonseminomatous mediastinal germ cell tumor and an associated hematological neoplasm that usually involve the megakaryocytic lineage. The hematopoietic malignancies can involve the mediastinum or present as infiltration of bone marrow or lymphoid organs. In majority of cases, the hematological malignancy was detected in the bone marrow simultaneously or within 6months after the detection of mediastinal germ cell tumor. There are very few limited case reports on the presence of hematopoietic or leukemic cells within the germ cell tumor itself and mass formation due to myeloid sarcoma is exceptionally rare. Herein we report the case of a 36-year-old male patient with a large mediastinal mass, excision biopsy of which showed areas of yolk sac tumor, immature teratoma and a separate round cell component. On immunohistochemical examination, the round cell component showed positivity for CD45 (dim), CD43, MPO, CD11c, and CD68 and were negative for CD117, CD20, CD5, CD34, Tdt, CD30, CD123, and CD61. A diagnosis of mediastinal germ cell tumor with yolk sac tumor and immature teratoma components and associated myeloid sarcoma was given. Peripheral smear and bone marrow examination showed no evidence of leukemic involvement.