Question about appropriate biopsy type

I'm not an expert, so maybe I'm wrong, but a shave is not the right biopsy for melanoma.  If it's believed to be melanoma, a full excision is recommended and if that's not possible for some reason, a punch biopsy is second best.

If you don't believe it to be melanoma and/or are concerned about the cosmetics of a scar would be a couple of reasons for doing a shave.

A derm that does shave biopsies on suspected melanoma is lazy and not doing their job properly. Punch biopsies for small moles that a derm suspects melanoma is most common. For larger lesions, and the answer your question about this subcutaneous situation, excisional biopsy would be best.

From now on, tell your derm you refuse shave biopsies, if she says too bad that's all I do, then get a different derm. 

Some derms will argue that a deep shave is totally appropriate for melanoma – especially if the lesion is a larger one.  I'm not a fan.  Shaves can bisect a lesion which compromises staging.  But for me, shaves are also more painful healing and look worse afterwards.  A punch is a full skin thickness biopsy – so better for assessing depth if something were melanoma.  But punches cannot get really large lesions.  Excisional biopsy is also appropriate but most docs won't do that unless they are really positive it is melanoma.  It's a more invasive surgery.  Each biopsy type has its pros and cons depending on the lesion being removed and what is suspected.  Your description of "slightly subcutaneous" reminds me more of a dermatofibroma.

Discuss the biopsy types with your doc.  This is your body.  For me, a simple punch biopsy (which requires 1-2 stitches to close and possibly a followup appt to remove) heal much cleaner and hurts less.  As for determining the nature of what is being removed, any biopsy type will most likely be fine. 

If I am wrong about this, I hope someone will correct me. I have wondered about the whole shave biopsy thing since my surgical oncologist made an offhand remark that "he didn't know why all the South Florida derms prefered shave biopsies". I wonder if extra insurance payment hassle, return scheduling and the more time required to educate the patient (+ complications, etc.) about something the MD would prefer not to do anyway color this alleged preference.

The discussion followed my noting to him that there are clinical trials that require preservation of tumor mass. Point 1 for excision. Unusual, but possibly of consequence.

Point 2 is really what I wonder about.  Since reading about Decision Dx, my understanding is that with tumor mass you can determine class I or class II metastatic status, which may be of enormous consequence in future decision making.

I don't know if you are talking about measurable tumor mass (which you hopefully won't find) or if this test would apply to you personally. But it's for I's and II's and maybe ask the MD about it and what is required. Clearly there are regular experiences where the "standard of care for a dermotological practice" is already sub-optimal for the undiagnosed melanoma population.

Being previously diagnosed, previously metastatically "un-classed", and facing possible reoccurance of capturable tumor mass, I wonder if excision isn't "indicated", as they say.

Good luck with your benign cyst….