An otherwise healthy 63-year-old white male presents with a bump on the left posterolateral neck (Lesion B). He went to his primary care physician to examine this lesion after being diagnosed with an unknown type of skin cancer near the right lateral eye several years ago. The bump on the neck may have changed, but it is difficult for the patient to see the area. He does not use sun protection and reports one severe sunburn as a child. He denies tanning bed use.
What is your best and most important next course of action?
A. Excisional biopsy or deep shave biopsy of Lesion A
B. Excisional biopsy or deep shave biopsy of Lesion B
C. Cryodestruction of Lesion A
D. Cryodestruction of Lesion B
E. Monitoring of Lesions A and B
ANSWER:
A. Excisional biopsy or deep shave biopsy of Lesion A
DISCUSSION
Lesion B (Figure 1) is the patient's primary complaint; it is relatively benign appearing and is likely a seborrheic keratosis, and although it may be sampled simultaneously, it should not take priority over Lesion A. Lesion A (Figure 1) shows several concerning clinical features of a melanocytic lesion. Whereas Lesion B may be concerning, the pigmentary changes of Lesion A are more concerning and must be investigated promptly.
Clinical findings that suggest regression can be a first clue to the diagnosis of melanoma, and they differ from the typical criteria used to identify melanoma. Although the absolute prognostic implications are not definitive, the diagnostic potential is critical and can be easily mistaken if the practitioner is not familiar with the findings of regression. The blue and white scar-like changes vary greatly from the traditionally hyperpigmented papule or the more atypical erythematous amelanotic melanoma but are a critical diagnostic feature to not be missed on a physical examination. Although addressing the patient's complaints is important, prioritizing concern for a melanocytic lesion should be the dermatologic provider's priority.
The hypopigmentation seen in Lesion A is concerning for the regression of an atypical melanocytic lesion. The bluish hue in a melanocytic lesion may represent significant melanin within the dermis, either as melanocytes or within melanophages (Bassoli et al., 2011). Some dermoscopic clues to melanoma regression (blue-white structures in general) can be seen in up to 80% of melanoma in situ cases, making them helpful clinical clues to the provider (Bassoli et al., 2011). Reticular patterning of blue regression is particularly helpful, as are the white scar-like areas with blue granularity, which are particularly concerning for melanoma (Ribero et al., 2016). Regressed melanomas are more often macular (Aung, Mutyambizi, Danialan, Ivan, & Prieto, 2015). It has been reported that the risk of melanoma is higher when the blue-white regression structures represent over 50% of the entire lesion (Ribero et al., 2016).
In a large study of 664 patients with melanoma, 25.5% showed regression. These patients were more likely to be men, and tumors were more likely to have a Breslow depth of less than 2 mm and be of the superficial spreading subtype (Tas & Erturk, 2016). Regression characteristics were not seen to correlate with age, mitotic rate, or vertical growth phase. Ultimately, this series showed no statistically significant association between regression and prognosis or survival (Tas & Erturk, 2016). However, complete regression of a primary melanoma with metastases may have a poor prognosis (Aung et al., 2015). Partial regression has a less clear effect on outcomes with tumor thickness being a more influential marker for sentinel lymph node metastasis (Fontaine, Parkhill, Greer, & Walsh, 2003). Vitiligo presenting secondary to immunotherapy for melanoma, although rare, is associated with increased survival (Teulings et al., 2015), suggesting a positive effect of regression on prognosis.
The typical histopathology of a regressed lesion shows a lichenoid, lymphoplasmacytic infiltrate with many lymphocytes and plasma cells at the dermal-epidermal junction. There are many melanophages within the fibrosed papillary dermis, with or without an atrophic, hypopigmented epidermis (Aung et al., 2015). This is what was seen in this patient's pathology with a melanoma in situ seen within the epidermis, and Melan-A staining showed pigment as deep as 0.5 mm into the dermis. The dermal component and staging of a potential melanoma encourage a deeper excisional biopsy of concerning lesions.
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