Differential Diagnosis for Black 1cm Discoloration in Posterior Part of Auricle in 1.5 Years Old Boy

• Single Most Likely Diagnosis
  • Hematoma: This is a common condition in children, especially after minor trauma, which could lead to a collection of blood under the skin, presenting as a black discoloration.
• Other Likely Diagnoses
  • Ecchymosis: Similar to hematoma, ecchymosis refers to bruising that could occur due to trauma, and its appearance can vary from blue to black.
  • Melanocytic Nevus (Mole): Although less common in this specific location and age group, a mole could present as a black discoloration.
  • Pyogenic Granuloma: Although typically more vascular in appearance, a pyogenic granuloma could potentially present with a dark coloration, especially if there's significant bleeding or scabbing.
• Do Not Miss Diagnoses
  • Malignant Melanoma: Although extremely rare in children, missing a diagnosis of malignant melanoma could be catastrophic. It's essential to consider this, especially if the lesion has irregular borders, is asymmetrical, has multiple colors, or is rapidly changing.
  • Angiosarcoma: Another rare but aggressive tumor that could present with a blue-black discoloration due to its vascular nature.
• Rare Diagnoses
  • Congenital Melanocytic Nevus with Atypical Features: While congenital nevi are not uncommon, those with atypical features or located in unusual areas like the posterior auricle might be considered rare.
  • Dermatofibroma: Typically presents as a firm, brown to purple nodule, but could potentially appear black, especially if there's significant hyperpigmentation.
  • Kaposi's Sarcoma: Extremely rare in children, especially without immunocompromisation, but could present with pigmented lesions.

Each diagnosis is considered based on the clinical presentation of a black discoloration on the auricle of a young child, with an emphasis on distinguishing between common, less common, critical, and rare conditions. The justification for each includes the typical presentation, age considerations, and the potential for the condition to mimic the described symptoms.