Melanoma accounts for the majority of deaths resulting from skin cancer. It is an aggressive malignancy of the pigment-producing melanocytes. | Medcomic/Jorge Muniz
Contents
Melanoma, also known as malignant melanoma, is a type of cancer that develops from the pigment-containing cells known as melanocytes.
BRAF (proto-oncogene, somatic mutation): Also found in non-Hodgkin lymphoma, papillary thyroid carcinoma
CDKN2A (Tumour suppressor gene, germline mutation): Also found in pancreatic cancer
The Calgary Guide | http://calgaryguide.ucalgary.ca/
Presentation
ABCDE rule:
ABCDE rule, encompasses several clinical features of melanoma, including Asymmetry, Border irregularity, Color variation (both intralesional color variation as well as a color that is different from the patient’s other nevi), Diameter > 6mm, and Evolving (a new or changing lesion).
Asymmetry
Border: Irregular
Colour: Multiple
Diameter: > 6 mm
Enlarging or evolving
ABCD rule illustration: On the left side from top to bottom: melanomas showing (A) Asymmetry, (B) a border that is uneven, ragged, or notched, (C) coloring of different shades of brown, black, or tan and (D) diameter that had changed in size. The normal moles on the right side do not have abnormal characteristics (no asymmetry, even border, even color, no change in diameter). | By Unknown creator; six images merged by User:Stevenfruitsmaak – National Cancer Institute via Skin Cancer Foundation, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5582818
Ugly duckling sign:
The Ugly Duckling Sign – SkinCancer.org. (2017). Skincancer.org. Retrieved 4 September 2017, from http://www.skincancer.org/skin-cancer-information/melanoma/melanoma-warning-signs-and-images/the-ugly-duckling-sign
Little Red Riding Hood sign:
Melanoma is observed to differ from naevi only when seen close-up – the sharp teeth of the wolf
Indicator for patients with fair skin and light-colored hair that are likely to suffer from amelanotic melanomas, which can be difficult to see and, therefore, diagnose
Numerous neurofibromas and one café au lait spot on the trunk. The black arrow indicates a light brown nodule with a pinkish halo. | Giuffrida, R., Uranitsch, M., Schmid, K., Deinlein, T., Favero, F., & Zalaudek, I. (2017). Hypomelanotic melanoma detected by the “little red riding hood sign” in a patient with neurofibromatosis type 1. Dermatology practical & conceptual, 7(4), 71–73. https://doi.org/10.5826/dpc.0704a14
Morphological types:
Superficial spreading
Nodular
Lentigo maligna
Acral lentiginous (highest prevalence in African-Americans and Asians)
Clinical spectrum of cutaneous melanoma morphology | Klebanov, N., Gunasekera, N. S., Lin, W. M., Hawryluk, E. B., Miller, D. M., Reddy, B. Y., Christman, M. P., Beaulieu, D., Rajadurai, S., Duncan, L. M., Sober, A. J., & Tsao, H. (2019). Clinical spectrum of cutaneous melanoma morphology. Journal of the American Academy of Dermatology, 80(1), 178-188.e3. https://doi.org/10.1016/j.jaad.2018.08.028
This image depicts a patient’s chest, which displays numerous darkly-pigmented cutaneous lesions, which had been diagnosed as malignant melanoma (MM). When diagnosing MM from a gross pathologic perspective, i.e., with the naked eye, a physician must keep in mind the “ABCDE” rule, which represents: – A = Asymmetry – Is the shape of the lesion(s) symmetrical, evenly distributed/shaped? – B = Border Irregularity – Is the border of the lesion(s) smooth or rough? – C = Color Variability – Is the lesion(s) multicolored, or of a single color? – D = Diameter – Is the lesion(s) greater than 6mm (0.24in.)? – E = Evolution – How did the lesion(s) evolve over time, i.e., did it appear, or change, quickly, or over a long period of time? | CDC/ Carl Washington, M.D., Emory Univ. School of Medicine; Mona Saraiya, MD, MPH – CDC PHIL, #13444, Public Domain, https://commons.wikimedia.org/w/index.php?curid=16362051A melanoma of approximately 2.5 cm by 1.5 cm | National Cancer Institute (AV Number: AV-8500-3850; Date Created: 1985; Date Entered: 1/1/2001), http://visualsonline.cancer.gov/details.cfm?imageid=2184, Public Domain, https://commons.wikimedia.org/w/index.php?curid=859342
Common sites:
Most common sites for melanoma to spread
| Cancer Research UK – Original email from CRUK, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34334124Where melanoma is most likely to develop
| Cancer Research UK – CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34334343
Case study:
Diagnosis
Punch biopsy:
Cellular atypia
Mitosis
Melanocyte cyst
Dermal invasion
a) Picture of a nevus presenting regular border. b) Picture of a dysplastic nevus presenting irregular border and microstructures. c) Histopathological cut of a melanoma presenting melanoma nests. d) Picture of a nodular melanoma. Figures a), b) and d) were kindly given by Dr. Pascale Guitera. Figure c) was taken from the work of Viros | Balois, T., Amar, M. Morphology of melanocytic lesions in situ. Sci Rep 4, 3622 (2014). https://doi.org/10.1038/srep03622
Breslow thickness:
Depth of tumor (Breslow thickness) correlates with risk of metastasis:
Tis: Melanoma only in epidermis
T1: Melanoma is ≤ 1 mm thick
T2: Melanoma is 1.1-2 mm thick
T3: Melanoma is 2.1-4 mm thick
T4: Melanoma is > 4 mm thick
Staging of melanoma—TNM staging and Breslow thickness. (n.d.). Retrieved July 26, 2022, from https://www.macmillan.org.uk/cancer-information-and-support/melanoma/staging-of-melanoma
Management
Primary treatment:
Excision with appropriately wide margins
Metastatic or unresectable melanoma (BRAF V600E mutation):
