This case describes a 58-year-old Fitzpatrick II White male with no significant past medical history who presented to the office for a skin check. He grew up in Florida and has had significant sun exposure throughout his life. Additionally, he works outside in construction and only intermittently uses sunscreen. He has had many spots frozen but has never been diagnosed with a skin cancer. His father had many moles removed and he believes he had skin cancer, but he is not sure what kind. 

At the beginning of the exam, he pointed out a new spot that he first noticed 2 years ago. He says the spot occasionally itches and has bled a few times in the past year. He also notes that it has gotten progressively bigger over the last two years. On exam, on the left lateral neck there is 5.1 cm x 3.4 cm erythematous plaque with scale and a 3 cm x 1.5 cm central ulceration. He previously tried using over-the-counter hydrocortisone 1% cream without any improvement. 

Physical Exam, Lab Results and Medical History 

A biopsy was performed which showed a poorly differentiated squamous cell carcinoma (SCC). Given that the tumor had several high-risk features, the specimen was sent to Castle Biosciences for DecisionDx-SCC testing to further assess the tumor’s risk of metastasis. 

Diagnostic Review 

Important considerations when diagnosing this patient included the location of the lesion, the patient’s personal history of sun exposure, and his family history of skin cancer. Additionally, the progression of the lesion over time and its persistence and growth with occasional bleeding raise suspicion for a malignancy. 

Once the biopsy confirmed a diagnosis of SCC, it was critical to assess the patient’s prognosis. While SCC typically has an excellent prognosis and 5-year cure rates greater than 90%, up to 6% of these tumors will metastasize.^1,2 Metastasis significantly worsens survival, with the 5-year survival rate dropping to 50% to 83% for regional metastasis and below 40% for distant metastasis.³ 

There are 2 commonly used staging systems for SCC, the Brigham and Women’s Hospital (BWH) classification and the American Joint Cancer Committee eighth edition (AJCC8) staging system. These systems use pathologic data to stage SCC but have several limitations that lead to a low sensitivity (23%-46%) and positive predictive value (12%-13%).⁴ Utilizing genomic testing through the 40-gene expression profile (GEP) test has been shown to be an independent and accurate predictor of metastatic risk. Additionally, using this test in conjunction with the BWH and AJCC8 staging systems has also been shown to further improve prognostic assessment.⁵ 

Thus, for a very large SCC such as the one seen in this case, or any tumor with at least 1 other high-risk feature, the 40-GEP test (DecisionDx-SCC) is a helpful way to assess a patient’s risk of metastasis and adjust management decisions accordingly.