Squamous Cell Carcinoma: Diagnosis and Management

00:01 The clinical presentation overall for cutaneous squamous cell carcinoma.

00:04 It can occur on any surface.

00:07 And it can also occur in oral and anogenital mucosa.

00:10 And it doesn't necessarily require prior UV exposure.

00:14 Clearly, fair-skinned individuals with lots of UV are going to have the most common kind of predilection for disease, and it will be in those sun-exposed areas.

00:26 In dark-skinned individuals who have good melanin protection against UV damage, the majority of the cutaneous squamous cell carcinomas will appear in non-sun exposed areas driven by other kind of risk factors, and up to 40% in those individuals will arise from chronic scarring lesions.

00:46 Again, because chronic inflammation is going to drive proliferation of epidermal keratinocytes, but also is going to create an environment where there are reactive oxygen species that can induce mutations in those proliferating cells. A squamous cell carcinoma can be well differentiated.

01:05 And I'll show you an example of what that looks like. Meaning that as as we look down the microscope at it, it looks very much like kind of normal skin just it is funky. Funky is one of those very important medical terms. It doesn't quite look normal, but it looks a lot like skin that's well differentiated and grossly, that's reflected by more indurated areas of the skin.

01:31 There may or may not be ulceration as we exceed the the ability of the vasculature to, to provide nutrition to the lesions.

01:42 On the other end of the spectrum is poorly differentiated.

01:45 The cells in those tumors do not look like normal keratinocytes at all. And those will have a slightly different kind of characteristics.

01:54 Grossly. This is not 100%.

01:57 I ultimately calling something well or poorly differentiated is going to come down to looking down the microscope and and pronouncing them as they look kind of normal or they look very bizarre.

02:10 Um, commonly, uh, squamous cell carcinomas of the skin are asymptomatic. However, if there is perineural invasion, if there is an elaboration of cytokines from inflammatory cells trying to destroy them, they may be painful or pruritic.

02:27 And then with very high-risk squamous cell carcinomas of the skin, um, that where there is a lot of perineural invasion, you may actually cause dampening of the of the sensation and have paresthesias. I promised that I would show you what a marjolin's ulcer looked like. Remember, this is squamous cell carcinoma arising in a chronic area of inflammation or chronic non-healing wound.

02:54 It initially looks like, gee, that wound is just not healing.

02:59 But in fact, what you are beginning to see over time is the evolution of a fairly aggressive squamous cell carcinoma.

03:08 Variants on this overall theme.

03:10 So keratoacanthomas shown there.

03:13 It's a very well-differentiated cutaneous squamous cell carcinoma in some textbooks not here but in some places you may see this as a completely separate entity.

03:24 It's just a well differentiated squamous cell carcinoma.

03:27 They're dome-shaped . It looks like they have a central crater or ulceration. That's just a central core of keratin being made by these well-differentiated tumor cells.

03:38 You can also have verrucous that looks like a big wart, kind of a large cauliflower lesion.

03:45 And verrucous carcinomas are again basically well-differentiated versions. They occur in the around the oral area, you know, genital area or as shown here, plantar lesions.

03:58 The diagnosis. So you don't I mean you should always get a good clinical history but you don't need it.

04:05 Physical exam. What does it look like including dermoscopy.

04:10 And then the for the gold you go for the biopsy.

04:14 You need to perform that for a definitive diagnosis.

04:18 Squamous cell carcinomas can look like a variety of other things including benign things. So you need to take it off, send it off to pathology and get the definitive diagnosis. Your way of sampling that can be a shave, it can be a punch or it can be completely excisional.

04:34 So the morphology. So when a squamous cell carcinoma in situ, just the layer of the epidermis from the basal layer up to the surface shows malignant cells, cells that are exceptionally atypical.

04:48 And it. And the important part about squamous cell carcinoma in situ is that it is not invaded beyond the basement membrane.

04:55 Okay. So atypical keratinocytes no invasion and excision will be entirely curative.

05:04 Now invasive squamous cell carcinoma shown here.

05:07 This is a very well differentiated tumor.

05:11 There are these big whorls and pearls of keratin.

05:14 Yeah. These cells are still thinking their skin cells.

05:17 And they're trying to make keratin for a stratum corneum layer. But they're making it in the middle of a collection of cells.

05:26 So it's, it is a little bit abnormal maturation.

05:30 Yep. And the cells are not quite like normal keratinocytes.

05:34 Again I'm not trying to turn you into a dermatopathologist just yet, but hopefully you would recognize this because of the keratin as something that is pretty well differentiated, but also quite invasive.

05:47 We can look for perineural invasion that typically signifies a bad acting tumor that's likely to metastasize, and we can do staining for other sorts of things where it's not obvious in poorly differentiated tumors that we're dealing with a squamous cell carcinoma.

06:02 How do we manage these.

06:04 Well first line treatment is get rid of it.

06:07 And in in areas say on the middle of the face where you want to be not so aggressive in terms of lopping off a nose or something.

06:15 We'll do Mohs micrographic surgery.

06:18 What is that? So you do a thin slice, you send it to pathology and say, is there tumor or is there not tumor? If there's tumor, you do another thin slice and basically you just shave off until the pathologist says there's no more tumor.

06:33 That is the best way to not take more than what you need.

06:37 And for areas that are, um, are very sensitive or can be disfiguring. Like the face. That's what we'll do.

06:44 Alternatives to surgery include zapping it using cryotherapy, liquid nitrogen, and topical chemotherapies. Radiation may be used for, uh, for disease in certain areas.

07:01 Interestingly, we said radiation can cause squamous cell carcinomas.

07:04 Yes, it can, but you can also treat it by causing increased numbers of DNA breaks. And eventually the cells become so weird that they just kill themselves. Uh, immunotherapy is useful, and chemotherapy are very important for more systemic disease, metastatic disease, and sometimes for locally and advanced disease. And with that, we've covered the second most common cause of cancer in the entire world.

07:35 Uh, squamous cell carcinoma.

07:37 Thank you.