Good news! It's not cancer.

 I had a scary looking thing on my hand that was growing like wildfire and pretty much matched the description of squamous cell carcinoma. Six weeks ago it was just a flat brown spot pretty much like all the other age spots on my hands except larger than most (about 1 cm). Then sometime in mid-October a small scaly patch appeared, getting a little bigger each day.

By last week the scaly patch covered most of the brown spot, had thickened a lot and developed a depression in the middle. All of this is characteristic of squamous cell, including that dimple in the middle, so I decided I'd better get it looked at. Health Partners online scheduling is useless when you actually need care within the next 3 weeks and they don't answer the phone any more, but my clinic responds well to online messaging and I managed to get an appointment for the next day. Without any prompting from me, the doctor said it looked like squamous cell and did a biopsy. She also put an "urgent referral" in my chart which allowed me to get an appointment with a dermatologist for just 6 days later (even she was surprised that worked!). And she somehow prioritized the biopsy request so I would actually get a result before the dermatology appointment. I guess that worked too, because I got the results today.

I wasn't familiar with many of these words, but the word benign stood out.

 

Sections show a lichenoid tissue reaction.  The differential diagnosis includes a benign lichenoid keratosis as well as a lesion of lichen planus. There is no evidence of a melanocytic proliferation in the sections examined.

 

Of course I looked up the rest of it and learned that a lichenoid tissue reaction is an "auto-immune attack by T cells on the epidermis" that can manifest in all sorts of forms, very few of which look at all like the thing on my hand. It's most commonly caused by a reaction to various medications and vaccines, in which case it is referred to as Lichenoid Drug Eruptions (LDE). When the precipitating factor is a vaccination, it is sometimes called V-ILE (Vaccine-Induced Lichenoid Eruption). Memorable acronym. 

There has been no change in my medications for at least 18 months, but ... 

• October 8 I had an RSV vaccination, which was (naturally) new to me
• The keratosis on my hand appeared about a week later. 

Smoking gun? Maybe. I'll mention it to the dermatologist and see what she thinks. V-ILEs have been associated with a number of vaccines: influenza, hepatitis, shingles, COVID, and others. So far not the RSV shot, but it's brand new. And although this is apparently a well-documented vaccine side effect, it is described as "uncommon."