‘Premycotic’ Eruptions
© Dr. Maged N. Kamel Boulos - MediCAD Multimedia, 1995-98. All rights reserved.
Mycosis fungoides (MF) does not develop from other dermatoses. Names like parapsoriasis en plaque, parapsoriasis variegata and poikiloderma atrophicans vasculare are simply descriptive terms of large patch lesions of MF. Such antiquated and confusing terms are better abandoned.
Classification of ‘premycotic’ eruptions (terms in italics are the recommended new nomenclature):
Parapsoriasis en plaque: not all types are ‘premycotic’
Prereticulotic (large plaque type): when the histology is not (yet) confirmatory, the condition can be designated ?MF stage T0 or premycosis.
Benign (small plaque type): chronic superficial scaly dermatitis or persistent superficial dermatitis (other names: digitate dermatosis, xanthoerythroderma perstans).
Poikiloderma atrophicans vasculare (PAV): not all types are premycotic
MF-associated, prereticulotic poikiloderma (parapsoriasis variegata): the histological picture is usually diagnostic of MF (more pronounced infiltrate than in ordinary non-MF-associated poikiloderma, MF or Lutzner cells may be seen as well as epidermotropism); the condition can be designated poikilodermatous MF—MF T1 or stage IA.
Non-MF-associated poikiloderma: poikiloderma totally unrelated to MF found in association with lupus erythematosus, dermatomyositis, drug eruptions, some genodermatoses, etc.
Prereticulotic eruption ?MF stage T0 or premycosis |
Persistent superficial dermatitis |
Often faintly yellowish |
Erythematous, pink, brown or slightly yellow |
The lesions are fewer but larger, having irregular bizarre or angular shapes; they are less sharply defined |
The patches are more numerous, about 2.5 cm across and have regular round, oval or finger-like shapes |
Fine scales |
Slightly scaly patches showing coarser scale |
Poikilodermatous changes may develop (poikilodermatous MF—MF T1 or stage IA—old name: parapsoriasis variegata) |
The lesions are all the same colour. Mild atrophy may develop, but not frank poikilodermatous changes (if reticulate pigmentation or frank atrophy develop, reclassify as prereticulotic eruption) |
May be irritable/itchy |
Little or no irritation/itching |
Progresses to cutaneous lymphoma |
Does not become malignant |
Histology: |
|
Absence of epidermal eczema; epidermotropism |
May be eczematous changes (spongiosis, exocytosis) |
Dermal infiltrate |
Little or no perivascular dermal infiltrate |
© Dr. Maged N. Kamel Boulos - MediCAD Multimedia, 1995-98. All rights reserved.