14th July 2026

Diagnosis

History and examination

Rapidly enlarging, shiny, smooth-surfaced solitary red nodule. Commonly seen on the head and neck. Ulceration is rare and typically only occurs in advanced stages. Metastasis and lymph node spread are common.

AEIOU can be used to aid diagnosis:

• A: asymptomatic/non-tender
• E: expanding rapidly (≤ 3 months)
• I: immunosuppressed
• O: older than 50 years
• U: UV-exposed sites

Dermoscopy:

• Linear, irregular, and polymorphous vessels, poorly focused vessels, milky pink/white areas, and architectural disorder. 

Immunohistochemistry: 

• Positive immunostaining with low molecular weight cytokeratins, e.g., cytokeratin 20 (CK20), and neuroendocrine markers such as neuron-specific enolase, Chromogranin A and synaptophysin are typically positive. 
• Thyroid transcription factor (TTF1) is usually negative.

Histopathology: 

• Uniformly small, round blue cells with scanty cytoplasm and vesicular nuclei