A “Logarithmic Spiral” in the Brain: Images of an Intracranial Dermoid Cyst

Abstract

A logarithmic spiral is a self-similar spiral curve, which often appears in nature, e.g., mollusk shells. In the normal tissues of the human body, the cochlea is also an approximate logarithmic spiral. However, approximate logarithmic spirals are rarely, if ever, reported in tumors. Recently, we treated a 26-year-old woman with a one-year history of headache. Preoperative magnetic resonance imaging showed a possible brain tumor with radiological characteristics similar to a typical logarithmic spiral, which has seldom been observed before. Because of the obvious clinical symptoms and discomfort, as well as the possible presence of an intracranial tumor, we performed a craniotomy and tumor resection. Perioperatively, we found an intact tumor capsule, with contents that appeared like egg-drop soup mixed with hairs. A postoperative pathological diagnosis of a dermoid cyst was made. However, more interestingly, the logarithmic spiral could be described mathematically with a high goodness of fit. In this paper, we present this case with various clinical images.