Perforating Granuloma Annulare with Cysts and Comedones

Area of Science:

• Dermatology
• Pathology

Background:

• Granuloma annulare is a benign inflammatory skin condition.
• Actinic granuloma annulare is a rare variant typically affecting sun-exposed areas.

Observation:

• A 71-year-old woman presented with arcuate plaques on her elbows showing raised erythematous edges and central clearing.
• Lesions exhibited comedones and cysts, with dermatoscopy revealing pores and granuloma annulare changes.
• Biopsies confirmed granuloma annulare with granulomas adjacent to comedones and cysts, and elastophagocytosis by multinucleated giant cells.

Findings:

• Histopathology demonstrated transepithelial elimination of elastic fibers within cysts, a feature not previously reported in similar cases.
• The presence of comedones and cysts is highly unusual in granuloma annulare.
• This case uniquely showed transepithelial elastic fiber elimination, distinguishing it from prior reports.

Implications:

• The findings suggest a potential role for diabetes mellitus in the pathogenesis of this actinic granuloma annulare variant.
• Lesion improvement after diabetes mellitus control in most cases supports this association.
• This case expands the understanding of rare granuloma annulare variants and their potential associations.