Pericardial cysts make up 6-7% of all mediastinal masses. They can present at any age, but are most commonly diagnosed between the third and fifth decade of life. Females and males have approximately equal incidences of pericardial cysts. History
Pericardial cysts were first reported on during autopsies in the 19th century by pathologists. As the field of radiology progressed, pericardial cysts could be identified in living patients. In 1931, the first surgical resection of a pericardial cyst was performed by Otto Pickhardt at Lenox Hill Hospital in New York using a thoracoscopy. In 1943, Greenfield and his colleagues coined the term "spring water cysts" for pericardial cysts since the cysts contain clear fluid. == References ==
T-cell acute lymphoblastic leukemia may refer to:

T-lymphoblastic leukemia/lymphoma, a form of lymphoid leukemia and lymphoma
Adult T-cell leukemia/lymphoma, a rare cancer of the immune systems own T-cells