Melanoma and satellite blue papule

Area of Science:

• Dermatology
• Dermatopathology
• Medical Imaging

Background:

• Dermoscopic color interpretation depends on chromophore location within skin layers.
• Blue coloration in skin lesions can originate from both melanocytic and nonmelanocytic sources.
• Differentiating blue skin lesions requires careful clinical and dermoscopic evaluation.

Purpose of the Study:

• To present a case study of a blue skin lesion with an unusual etiology.
• To highlight the diagnostic challenges and differential diagnoses for blue lesions.
• To emphasize the role of integrated diagnostic approaches, including non-invasive imaging techniques.

Main Methods:

• Clinical presentation and patient history.
• Dermoscopic examination of hyperpigmented patch and blue papule.
• Reflectance confocal microscopy and high-definition optical coherence tomography.
• Histopathological examination post-excision.

Main Results:

• A hyperpigmented patch was diagnosed as melanoma in situ.
• A blue papule, initially concerning for malignancy, was identified as a foreign body reaction from a 75-year-old grenade injury.
• Histopathology confirmed the final diagnoses for both lesions.

Conclusions:

• The diagnostic evaluation of blue skin lesions necessitates integrating clinical, dermoscopic, and histopathological data.
• Non-invasive imaging modalities like RCM and HD-OCT can assist in the differential diagnosis of blue lesions.
• Foreign body reactions can present as blue papules, mimicking other pigmented lesions.