- Megalerythema (epidermicum) (infectiosum) 057.0
- Megalia, cutis et ossium 757.39
- Megaloappendix 751.5
- Megalocephalus, megalocephaly NEC 756.0
- Megalocornea 743.41
- Megalocytic anemia 281.9
- Megalodactylia (fingers) (thumbs) 755.57
- Megaloduodenum 751.5
- Megaloesophagus (functional) 530.0
- Megalogastria (congenital) 750.7
- Megalomania 307.9
- Megalophthalmos 743.8
- Megalopsia 368.14
- Megalosplenia (see also Splenomegaly) 789.2
- Megaloureter 593.89
- Megarectum 569.49
- Megasigmoid 564.7
- Megaureter 593.89
- Megrim 346.9
- Meibomian
- Meibomitis 373.12
- Meige