Follicular Granular Parakeratosis: A Case Report, Literature Review, and Proposed Classification.

Area of Science:

• Dermatology
• Histopathology

Background:

• Granular parakeratosis (GP) is an acquired keratotic dermatosis typically affecting intertriginous areas.
• Follicular involvement in GP can extend from interfollicular epithelium or originate primarily from the follicular epithelium.

Observation:

• Follicular GP is an extremely rare variant of GP, with only one prior case reported in medical literature.
• This study presents the second reported case of follicular GP.
• The patient was a 52-year-old Thai male who developed facial papules after using anti-melasma cream.

Findings:

• The patient presented with multiple tiny, filiform hyperkeratotic papules on his face.
• The condition, follicular GP, was diagnosed based on clinical presentation and histopathological findings.

Implications:

• This case expands the understanding of follicular GP presentation and potential triggers.
• A proposed classification for GP based on clinical and histopathological features is introduced.
• Further research may elucidate the pathogenesis and optimal management of follicular GP.