- Leukopenia 288.0
- Leukopenic - see condition
- Leukoplakia 702.8
- Leukopolioencephalopathy 330.0
- Leukorrhea (vagina) 623.5
- Leukosarcoma (M9850/3) 207.8
- Leukosis (M9800/3) - see Leukemia
- Lev's disease or syndrome (acquired complete heart block) 426.0
- Levi's syndrome (pituitary dwarfism) 253.3
- Levocardia (isolated) 746.87
- Levulosuria 271.2
- Lewandowski's disease (primary) (see also Tuberculosis) 017.0
- Lewandowski-Lutz disease (epidermodysplasia verruciformis) 078.19
- Lewy body dementia 331.82
- Lewy body disease 331.82
- Leyden's disease (periodic vomiting) 536.2
- Leyden-Möbius dystrophy 359.1
- Leydig cell
- Leydig-Sertoli cell tumor (M8631/0)
- LGSIL (low grade squamous intraepithelial lesion) 795.03
- Li-Fraumeni cancer syndrome V84.01
- Liar, pathologic 301.7
