- Grading of histological parameters for the assessment of suspected mycosis fungoides.
| Histological criteria | Grade 0 | Grade 1 | Grade 2 | Grade 3 |
|---|---|---|---|---|
| Epidermotropism | (-) | Focal (1-5/HPF) | Moderate (6-10/HPF) | Marked (> 10/HPF) |
| Pautrier’s microabscess | (-) | (+) | NA | NA |
| Spongiosis* | (-) | Mild (focal) | Moderate | Severe |
| Parakeratosis | (-) | Focal (<10%) | Moderate (10-50%) | Marked (>50%) |
| Pigment incontinence | (-) | (+) | NA | NA |
| Dermal infiltrates | (-) | Mild perivascular | Lichenoid pattern | Dense with adnexal structure |
| Dermal fibrosis | (-) | (+) | NA | NA |
| Atypical lymphocytes | (-) | 1–5/100 cells | 6–10/100 cells | >10/100 cells |
| Large cerebriform lymphocytes | (-) | 1–3/10 HPF | 4–5/10 HPF | >5/100 HPF |
| Adnexal involvement | (-) | (+) | NA | NA |
HPF: high-power field, NA: not applicable
↵* Spongiosis was assessed as follows: mild=degree of intercellular edema mildly greater than what would be typically expected for the interface change displayed within the specimen, moderate=moderate spongiotic change, severe=severe spongiotic change with vesicle or bullae formation.