Lichen myxedematosus: diagnostic criteria, classification, and severity grading.
BACKGROUND
Lichen myxedematosus (LM) is a rare, chronic idiopathic disorder characterized clinically by waxy, closely set papules and histopathologically by diffuse dermal mucin deposition and fibroblast proliferation. The most recent classification of LM was proposed in 2001; however, it seems to be complex, confusing, and imprecise. Herein, we present seven cases of LM to evaluate the validity of the current classification, to propose new diagnostic criteria and classification, and to suggest a clinically relevant severity grading system for this rare disorder.


METHODS
The study included seven patients with different presentations and severities of LM. All patients were subjected to thorough dermatological and systemic examination, routine laboratory tests, evaluation of thyroid function, protein electrophoresis, and detailed investigations to detect systemic involvement.


RESULTS
The current classification does not meet the requirements of proper diagnosis of different presentations of LM. Subtyping of the studied patients differs greatly according to the old classification and the newly proposed one. New diagnostic criteria, classification, and grading are consequently suggested.


CONCLUSIONS
We propose two sets of diagnostic criteria to define the disease more precisely and to avoid confusion associated with the other classification. The first set comprises constant clinical and histopathological features that are always present in every case, and the second set includes associated features that were variably reported in some patients. LM is then subclassified according to the presence or absence of systemic manifestations into a systemic severe form (scleromyxedema) and a non-disabling, pure cutaneous form.
Department of Dermatology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Ahmad
A
Nofal
Al-Haud Al-Marsoud Dermatology Hospital, Cairo, Egypt.
Hala
H
Amer
Department of Dermatology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Rania
R
Alakad
Department of Dermatology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Eman
E
Nofal
Department of Dermatology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Fatma El
FE
Desouky
Department of Dermatology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Ayman
A
Yosef
Department of Dermatology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Waleed
W
Albalat
Department of Dermatology, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
Khaled
K
Gharib
Department of Dermatology and Andrology, Faculty of Medicine for Girls, Al-Azhar University, Cairo, Egypt.
Inass
I
Mostafa
Al-Haud Al-Marsoud Dermatology Hospital, Cairo, Egypt.
Sahar
S
Fathy
Al-Haud Al-Marsoud Dermatology Hospital, Cairo, Egypt.
Monira
M
Waked
Al-Haud Al-Marsoud Dermatology Hospital, Cairo, Egypt.
Eman
E
Ragheb
Al-Haud Al-Marsoud Dermatology Hospital, Cairo, Egypt.
Hanan
H
Gammaz
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010265:Paraproteinemias / Q000209:etiology*; D053718:Scleromyxedema / Q000145:classification / Q000150:complications / Q000175:diagnosis* / Q000473:pathology*; D012720:Severity of Illness Index; D013959:Thyroid Diseases / Q000209:etiology*; D055815:Young Adult