Spongy tissue is a psychological disorder of the mango (and you thought only humans could be sensitive). The mango looks good from outside, but is spongy inside.
Spongy tissue cannot be identified in an unripe mango. However as the mango ripens, the area with spongy tissue will not ripen and will remain devoid of any nutrients- it will generally be white and spongy, hence the name.
We try our best to filter out the mangoes with spongy tissue at the source, but it is still an imperfect art and mango with spongy tissue does come through.
Generally, if a small portion exhibits this, it can safely be scooped away without affecting the remainder.
Sometimes the spongy area can change color with time and becomes black. The tissue which is good will always feel, taste and look good.
Picture1 shows a little spongy tissue which can be safely scooped away, Picture2 shows a spongy tissue that has become black.
Picture3 shows a full spongy tissue- nothing can be salvaged.