An 'aunt minnie' is a radiographic appearance diagnostic for a specific condition without much of a differential diagnosis.
(It is to the best of my knowledge a quote from some RSNA session in the pleiozaen of radiology. I don't recall who is quoted, but it goes something like: 'If I see an elderly lady coming through my front door, I can start to describe her hair, her clothing, the features of her face. But in the end it just IS aunt minnie because she LOOKS like aunt minnie')