Pathogenesis of Pseudocheckerboard Pattern in Mechanic's Hands.

Area of Science:

• Dermatology
• Immunology
• Pathology

Background:

• Mechanic's hands are a common dermatomyositis manifestation.
• The pseudocheckerboard pattern is a characteristic histopathological finding.
• The underlying mechanism of mechanic's hands remains unclear.

Purpose of the Study:

• To investigate the histopathological features and underlying mechanisms of mechanic's hands in dermatomyositis.
• To analyze the role of inflammatory cells and cytokines in the pathogenesis.

Main Methods:

• Collected tissue samples from 14 dermatomyositis patients with mechanic's hands.
• Reviewed clinical presentations and histopathological features.
• Analyzed lymphocyte infiltration and cytokine expression (IL-17).

Main Results:

• Confirmed the pseudocheckerboard pattern in mechanic's hands.
• Observed CD4+ and CD8+ lymphocyte infiltration in the papillary dermis and suprapapillary epidermis.
• Found IL-17 expression in lymphocytes, comparable to psoriatic lesions.

Conclusions:

• Th17-mediated epidermal hyperplasia is implicated in the pathogenesis of mechanic's hands.
• The findings provide insights into the inflammatory pathways involved in this dermatomyositis feature.