\[ \boxed { {x}^{2} \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}-2\,xy \left ( x \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) + \left ( y \left ( x \right ) \right ) ^{2} \left ( -{x}^{2}+1 \right ) -{x}^{4}=0} \]
Mathematica: cpu = 0.034504 (sec), leaf count = 26 \[ \left \{\left \{y(x)\to -x \sinh \left (x-c_1\right )\right \},\left \{y(x)\to x \sinh \left (c_1+x\right )\right \}\right \} \]
Maple: cpu = 1.809 (sec), leaf count = 59 \[ \left \{ y \left ( x \right ) =-ix,y \left ( x \right ) =ix,y \left ( x \right ) =-{\frac {{\it \_C1}\,x}{2\,{{\rm e}^{x}}} \left ( {\frac { \left ( {{\rm e}^{x}} \right ) ^{2}}{{{\it \_C1}}^{2}}}-1 \right ) },y \left ( x \right ) ={\frac {x \left ( \left ( {{\rm e}^{x}} \right ) ^{2} {{\it \_C1}}^{2}-1 \right ) }{2\,{{\rm e}^{x}}{\it \_C1}}} \right \} \]