A 58-year-old woman presents with a rapidly enlarging, pink, fleshy nodule on the upper back that bleeds on touch. It lacks any pigment clinically and dermoscopically shows atypical vessels rather than a pigment network. Which feature is MOST important in avoiding a missed diagnosis?
- A Pink colour indicates a benign angioma and observation is appropriate
- B Absence of pigment excludes melanoma and biopsy is unnecessary
- C Amelanotic melanoma should be considered in any rapidly growing vascular-appearing nodule that fails to behave like a pyogenic granuloma ✓
- D Amelanotic lesions are always metastatic deposits from an internal primary
Correct answer: C. Amelanotic melanoma should be considered in any rapidly growing vascular-appearing nodule that fails to behave like a pyogenic granuloma
Explanation
Amelanotic melanoma, comprising roughly 2 to 8 percent of melanomas, lacks clinically detectable pigment and mimics pyogenic granuloma, non-pigmented BCC, or a vascular lesion. Any new or changing pink nodule with atypical dotted or polymorphous vessels warrants biopsy. Absence of pigment does not exclude melanoma because these tumours still contain melanosomes demonstrable by immunohistochemistry.
Reference: Fitzpatrick's Dermatology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.