Skin Cancer- Is Keratoacanthoma a Distinct Entity or Squamous Cell Carcinoma?

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“Under the microscope, keratoacanthoma very closely resembles squamous cell carcinoma-non-melanoma skin cancer. In order to differentiate between the two, almost the entire structure needs to be removed and examined

Dear Cancer Coach:

Picture of Keratoacanthoma (1 of 2)

 I had a growth on my leg that was determined to be keratoacanthoma. A dermatologist cut it out and sent it to pathology. I haven’t received the pathology report myself yet. The dermatologist wants me to get a shot of 5FU instead of Mohs surgery. His comment was he didn’t want it to bite me 10 years down the road. I’m 75 and not sure I’ll be alive 10 years from now. If it isn’t SCC (non-melanoma skin cancer), should I have the 5FU or should I leave it alone? If it is SCC, then what?

Thanks for a reply. Sue


Hi Sue-

Let me ask you a few questions before we settle on your next steps.

1) When you say that your dermatologist “cut it out” are you saying that he/she removed the entire KC? If so the pathologist should be able to make a complete report. A report that you should be able to use to make better decisions.

2) Ask you can read from the bold face below, your decision-making may be influenced by a) KC or SCC b) specific diagnosis based on “the entire structure”

Under the microscope, keratoacanthoma very closely resembles squamous cell carcinoma. In order to differentiate between the two, almost the entire structure needs to be removed and examined. While some pathologists classify KA as a distinct entity and not a malignancy, about 6% of clinical and histological keratoacanthomas do progress to invasive and aggressive squamous cell cancers; some pathologists may label KA as “well-differentiated squamous cell carcinoma, keratoacanthoma variant”, and prompt definitive surgery may be recommended.[3][4][5][6]”

Finally, your instincts are accurate. 5-FU is chemotherapy and chemotherapy can mean collateral damage. It is difficult for any 75 year old to worry too much about the 10 year picture.

How do you feel about emailing me again once you receive the pathologist’s report?

thanks

David Emerson

  • Cancer Survivor
  • Cancer Coach
  • Director PeopleBeatingCancer

Keratoacanthoma

Keratoacanthoma (KA) is a common low-grade (unlikely to metastasize or invade) skin tumour that is believed to originate from the neck of the hair follicle.[1]

Under the microscope, keratoacanthoma very closely resembles squamous cell carcinoma. In order to differentiate between the two, almost the entire structure needs to be removed and examined. While some pathologists classify KA as a distinct entity and not a malignancy, about 6% of clinical and histological keratoacanthomas do progress to invasive and aggressive squamous cell cancers; some pathologists may label KA as “well-differentiated squamous cell carcinoma, keratoacanthoma variant”, and prompt definitive surgery may be recommended..

 

 

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