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Patient Case: Melanocytic Naevi (Moles)

Patient Case: Melanocytic Naevi (Moles)

Discussion

A 34-year-old woman visits a dermatology clinic for evaluation of multiple dark brown spots on her back and arms. She mentions that these spots have been present since childhood but have slightly increased in number over the years. The lesions are round to oval, smooth, and uniformly pigmented with well-defined borders. She denies any pain, itching, bleeding, or rapid growth.

Her medical history is unremarkable, but she reports frequent sun exposure during her teenage years due to outdoor sports. She has no family history of melanoma or other skin cancers. On physical examination, several small (3-6 mm) pigmented macules and papules are observed, all appearing symmetrical and evenly colored. A dermoscopic exam confirms the absence of concerning features such as irregular borders, color variegation, or ulceration.

Given the benign appearance of the naevi, the patient is reassured and educated on self-monitoring using the ABCDE criteria (Asymmetry, Border irregularity, Color variation, Diameter >6mm, and Evolution). She is advised to use sunscreen regularly and return for follow-up if any changes occur.

Questions
  1. What is the most likely diagnosis in this patient?
    a) Seborrheic keratosis
    b) Melanocytic naevi
    c) Actinic keratosis
    d) Malignant melanoma
  2. Which of the following features would be most concerning for malignant transformation in a melanocytic naevus?
    a) Symmetry and uniform color
    b) Increase in size, irregular borders, and color variation
    c) Presence since childhood without changes
    d) Lesions smaller than 6 mm with well-defined borders
  3. What is the most important risk factor for the development of melanocytic naevi?
    a) Family history of diabetes
    b) Frequent sun exposure during early life
    c) Fungal skin infections
    d) Contact with irritants like detergents
  4. Which of the following is the best management approach for this patient?
    a) Immediate excision of all lesions
    b) Reassurance, sun protection, and self-monitoring for changes
    c) Cryotherapy to remove the moles
    d) Topical steroid application for symptomatic relief
Reveal answers

Answers

  1.  (b) Melanocytic naevi
    • The patient's lesions are well-defined, symmetrical, and uniformly pigmented, which are characteristic of benign melanocytic naevi. Seborrheic keratosis has a "stuck-on" appearance, actinic keratosis presents with rough, scaly patches, and melanoma often shows asymmetry and color variation.
  2.  (b) Increase in size, irregular borders, and color variation
    • These are warning signs of malignant transformation based on the ABCDE criteria for melanoma. The patient’s naevi lack these concerning features, making malignancy unlikely.
  3.  (b) Frequent sun exposure during early life
    • UV exposure, particularly in childhood, is a major risk factor for the development of melanocytic naevi and melanoma. Genetic predisposition also plays a role, but factors like diabetes and skin irritants are not significant contributors.
  4.  (b) Reassurance, sun protection, and self-monitoring for changes
    • Since the naevi are benign with no alarming features, the best approach is to educate the patient about self-examination, sun protection, and monitoring for new or changing lesions. Routine excision is unnecessary unless there are concerning features.