lexus-is2

While doing my first oil change on my RWD IS250 yesterday, i noticed dirt stuck on one edge of the oil pan. It was along one of the edge and alot of dirt was stuck on it. It seemed a little greasy like there was a little oil there and dirt stuck to the oil. It wasnt wet or anything and there isnt any sort of dripping leak. Just wondering if this is and oil leak around this small section of the oil pan gasket. I've cleaned it up but will need to give it a good scrub and degrease so that i can carefully monitor it.

anyone noticed anything similar?