A histopathologic study of mechanic's hands associated with dermatomyositis: a report of five cases.
BACKGROUND
Mechanic's hand is a defined specific skin eruption associated with dermatomyositis; there are few reports concerning its histopathology. As mechanic's hand clinically resembles hand eczema, it is important to distinguish between these two conditions.


OBJECTIVE
To determine the characteristic clinical and histopathologic features of mechanic's hand, and to clarify whether these two conditions can be differentiated by histopathologic findings.


METHODS
We analyzed clinicopathologically five patients with mechanic's hands who visited our clinic between 2006 and 2007.


RESULTS
The clinical features of mechanic's hands were discrete hyperkeratotic erythema on the ulnar aspect of the thumbs and the radial aspect of the fingers. In all five cases, the histologic findings included marked hyperkeratosis, focal parakeratosis, psoriasiform acanthosis, and colloid bodies in the epidermis. There were mononuclear cell infiltrates around the blood vessels, and mucin deposition was observed in the dermis.


CONCLUSIONS
The histopathologic findings of mechanic's hands are specific and different from those of eczema. A histopathologic examination is useful for the diagnosis of mechanic's hands associated with dermatomyositis and a high incidence of interstitial pneumonia.
Mii
Sumiyuki
S
Department of Dermatology and Section of Allergy and Rheumatology, St. Luke's International Hospital, Tokyo, Japan. miisumi@med.kitasato-u.ac.jp
Kobayashi
Ritsuko
R
Nakano
Toshiaki
T
Harada
Harumi
H
Okada
Masato
M
Matsui
Yukio
Y
Fujii
Takao
T
Eto
Hikaru
H
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood; D001706:Biopsy; D001943:Breast Neoplasms / Q000150:complications; D003882:Dermatomyositis / Q000150:complications / Q000188:drug therapy / Q000473:pathology*; D005260:Female; D006229:Hand Dermatoses / Q000150:complications / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000473:pathology; D008025:Ligases / Q000276:immunology; D017563:Lung Diseases, Interstitial / Q000150:complications; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000150:complications
D000305:Adrenal Cortex Hormones; D000974:Antibodies, Antinuclear; D008025:Ligases