How can there be a systolic murmur in mitral stenosis without regurgitation in the mitral area?

Mitral stenosis: Aha! sophisticated question! you are correct in that mitral stenosis produces a loud s1, opening snap, followed by a diastolic rumble. It would be unusual to have the typical findings of mitral stenosis with significant mitral insufficiency. However! there can be associated abnormalities such as aortic stenosis which would produce a systolic murmur!

Pulmonary HTN: You're correct. Mitral stenosis produces a diastolic rumble or murmur. However, as mitral stenosis worsens patients develop pulmonary hypertension. This in turn will increase the pressure in the right ventricle which could induce a normal tricuspid valve to leak. This murmur would be systolic.