Pseudocyst of the auricle: case reports and its biochemical characteristics.

Pseudocyst of the auricle is a rare, asymptomatic cystic swelling of the auricle resulting from accumulation of yellow viscous fluid with unknown cause. We herein report 3 such patients in whom biochemical study of the aspirated fluid revealed markedly elevated activity of lactate dehydrogenase (LDH) and a preponderance of LDH-4 and LDH-5. We postulate that pseudocyst formation is due to the disruption of the auricular cartilage and that LDH in the fluid is released from the auricular cartilage. This observation supports that the lesions represent a pattern of chondromalacia. It is hypothesized that the cause of such pseudocysts is repeated minor trauma.