"What are the Breslow Depth Criteria and Clark Levels for Classifying Melanoma?"

1.20.24 Quick Review #96 - #pathology #oralpathology #doctorgallagher #oralsurgery #oralsurgeon #dentist #dentistry #dental #surgery #surgeon #omfs The Breslow Depth Criteria and Clark Levels are two methods used to describe the depth of invasion of melanoma in the skin, each with its own classification parameters: Breslow Depth: Breslow depth measures the vertical thickness of the melanoma from the top layer of the skin (the granular layer of the epidermis) down to the deepest point of tumor invasion. The Breslow depth has become the preferred classification because it is a more standardized method to measure melanoma depth. It requires an optical micrometer fitted to the ocular position of a standard microscope. It's expressed in millimeters and is divided into 4 categories: - 95% with excision. - 1.01 to 2.0 mm: Represents an intermediate thickness. - 2.01 to 4.0 mm: Considered a thick melanoma, associated with a higher risk of metastasis. - >4.0 mm: Very thick melanoma, indicates a higher risk of spread and a worse prognosis. Clark Level: The Clark level describes the anatomic layer of skin that the melanoma has penetrated and is less commonly used in current clinical practice: - Level I (Melanoma in situ): Confined to the epidermis (outer layer of skin). - Level II: Penetrates through the basement membrane and invades the papillary dermis (upper layer of the dermis). - Level III: Fills the papillary dermis and may encroach but not invade the reticular dermis (deeper layer of the dermis). - Level IV: Invades the reticular dermis. - Level V: Extends into the subcutaneous tissue. Breslow depth is generally considered a more accurate predictor of melanoma prognosis than the Clark level, as it is more directly correlated with the risk of melanoma metastasis. However, both systems can provide valuable information in assessing and managing melanoma. References: 1. Breslow, A. (1970). Thickness, cross-sectional areas and depth of invasion in the prognosis of cutaneous melanoma. Annals of Surgery, 172(5), 902-908. doi:10.1097/00000658-197011000-00017 2. Clark Jr, W. H., From, L., Bernardino, E. A., & Mihm, M. C. (1969). The histogenesis and biologic behavior of primary human malignant melanomas of the skin. Cancer Research, 29(3), 705-726. 3. Balch, C. M., Gershenwald, J. E., Soong, S. J., Thompson, J. F., Atkins, M. B., Byrd, D. R., ... & Coit, D. G. (2009). Final version of 2009 AJCC melanoma staging and classification. Journal of Clinical Oncology, 27(36), 6199-6206. doi:10.1200/JCO.2009.23.4799 4. McCarter, M. D. (2018). In H. M. Abernathy (Ed.), Abernathy's Surgical Secrets (7th ed.). Elsevier Inc. 5. ChatGPT. 2024.