Welcome back to the journal review. This is the February twenty twenty-six issue of Dermatologic Surgery, and we've got four pieces worth your time today — a diagnostic case report on acral melanoma versus postgraft pigmentation, an original survey study looking at the international state of Mohs training, a data-driven needs assessment from the American Board of Dermatology's certification program, and a case series on myopericytomas. Let's get into it.

First up is a case report titled Acral Melanoma Recurrence Versus Postgraft Pigmentation in a Darker Skin Patient. This is a single case, but it's the kind of diagnostic puzzle that's genuinely useful to have in your back pocket. A forty-one-year-old woman, Fitzpatrick type five, had a history of acral melanoma on the medial plantar foot, treated with wide local excision and a full-thickness skin graft from her thigh. She then developed a biopsy-proven recurrent melanoma in situ at that site, underwent Mohs micrographic surgery with clear margins, and was repaired again with a full-thickness graft — this time from her inner arm. Seven months later, a new hyperpigmented macule showed up right at the graft margin. Biopsy called it an atypical melanocytic proliferation favoring melanoma in situ, understandably given her history, so she went back to Mohs. Here's where it gets interesting: hematoxylin and eosin staining showed confluent melanin pigment along the basal keratinocytes, which on its own could easily be over-read as recurrent disease. But MART-1 staining — that's melanoma antigen recognized by T cells-1, the immunohistochemical marker Mohs surgeons commonly use intraoperatively for melanoma margin assessment — was negative for atypical melanocytes. The pigment was confined to melanin caps within basal keratinocytes, and there was a clean transition zone between the graft and the native acral skin. All of that argued for benign postgraft pigmentation rather than recurrence.

The authors' discussion is really the heart of this piece. Grafting pigment-rich donor skin — arm or thigh — onto acral sites which normally have much lower baseline melanin can produce exactly this kind of asymmetric hyperpigmentation, through either postinflammatory change or migration of melanocytes from the graft itself. This has been described before, including a similar skin type six case with a chest-derived graft on acral skin, and dermoscopy has been proposed as an adjunct to help distinguish the two scenarios. The teaching point for practice is straightforward: MART-1 is a great tool during Mohs for melanoma, but it stains benign melanocytes too, so in densely pigmented or sun-damaged skin you can get a false read toward malignancy if you're not also assessing the architecture — specifically, whether melanin is confined to basal keratinocyte caps versus infiltrating atypical melanocytes, and whether there's a sharp graft-to-recipient transition zone. Practically, if you're placing full-thickness grafts from pigmented donor sites onto acral or other low-pigment recipient beds in patients with skin of color, counsel them up front that hyperpigmentation at the graft margin is a known phenomenon, and make sure whoever's reading the frozen or permanent sections down the line knows the graft's donor origin — that context alone can prevent an unnecessary over-call.

Next is an original study, An International Perspective on Mohs Surgical Training, out of Stanford. This is a cross-sectional survey, and the gap they're addressing is pretty simple to state: Mohs micrographic surgery is the gold standard here in the States, but nobody has ever actually pulled together an aggregate picture of how it's taught and practiced globally. The authors built a forty-seven question online survey covering certification pathways, practice patterns, and barriers to growth, and distributed it over ten months, from August twenty twenty-three through May twenty twenty-four, both by direct email and through partnering international surgical societies. Why a survey, and why this design? The authors don't spell out an elaborate justification, but it's worth teaching the logic here — when no registry or aggregated dataset exists anywhere in the world, a self-reported cross-sectional survey is really the only feasible first step to generate any denominator at all. You're not testing a hypothesis so much as mapping unknown terrain, and that's a legitimate and common rationale for descriptive survey methodology as a foundational, hypothesis-generating step before anything more rigorous, like a formal registry, can follow.

The results: a hundred fifty-eight respondents from thirty-one countries, with the heaviest representation from Brazil, the UK, Switzerland, and the Netherlands. The vast majority — better than nine in ten — trained primarily in dermatology. About two-thirds completed their Mohs training in their home country, and of the ones who didn't, the overwhelming majority said it simply wasn't available there. Certification requirements were all over the map: roughly a third required a minimum of a hundred Mohs cases as primary surgeon, and about a quarter required a hundred repairs, but nearly a sixth of respondents reported no formal requirements at all. Formally accredited fellowships — the kind recognized by the ACGME, the Accreditation Council for Graduate Medical Education, or the Australasian College of Dermatologists — exist in only six countries worldwide: the US, Canada, Australia, New Zealand, the UK, and Israel. In terms of practice patterns, most respondents work in private or academic settings, and here's a number that should give you pause — about two-thirds are doing zero to five Mohs cases a week, which is a dramatically lower volume than typical US practice. Standard American-technique Mohs was the dominant margin-control method, used by about ninety percent, though a meaningful minority also use slow Mohs or the Tübingen-Torte technique. Only about a quarter perform Mohs for melanoma. Sixty percent interpret their own slides independently, while about a third co-interpret with a pathologist. And the barriers to growth were consistent and structural: lack of public awareness, limited infrastructure, and poor or absent reimbursement each cited by roughly a third to two-fifths of respondents. Strikingly, almost three-quarters of respondents said their country has no formal Mohs surgery society at all, and only about eight percent are ACMS members.

The authors' discussion frames this as evidence of real global disparity in training standardization, and they call for a more formal international registry going forward. The obvious limitations here are the ones inherent to any voluntary survey — self-selection bias, uneven response rates by country, and no way to know how representative these hundred fifty-eight respondents are of the true global population of Mohs practitioners, which the authors themselves acknowledge remains unknown. For your practice, this one is genuinely interesting rather than practice-changing — it doesn't change what you do Monday morning in clinic — but it's valuable context if you're involved in international fellow exchange, mentorship, visiting observerships, or society-level advocacy work, and it's a useful data point for anyone thinking about global standardization efforts in our field.

The third article is another data-driven piece: Cosmetic and Surgical Dermatology Learning Needs Identified Through Continuing Certification Program Assessments of the American Board of Dermatology. This isn't a clinical study, it's essentially a structured educational needs assessment, and it's built on the American Board of Dermatology's CertLink platform — the continuing certification program's web-based quarterly testing system. The rationale, and this one the authors do state explicitly, is that the American Board of Medical Specialties now requires member boards to identify recurring knowledge deficits and feed that back to specialty societies to guide continuing education. So the ABD mined its own test performance data from October twenty twenty-one through September twenty twenty-three to find out where board-certified dermatologists are systematically struggling.

Methodologically, this is worth pausing on because it's a nice example of applying psychometrics rather than just raw pass-fail counting. Every question went through what's called key validation first — ABD psychometricians looked at difficulty, essentially the percent answered correctly, and discrimination, whether the question actually separated stronger from weaker performers — and any question that seemed flawed rather than genuinely diagnostic of a knowledge gap was pulled before analysis. Only after that filtering did they rank questions by frequency of incorrect response and generate thematic groupings. That's a meaningfully different process than just reporting raw miss rates, because it tries to isolate true knowledge gaps from poorly written test items.

The scale here is substantial — over five hundred fifty thousand diplomate responses across three hundred forty-four questions, plus more than a hundred fifty thousand selected article reviews from a hundred thirty-eight articles. For cosmetic dermatology specifically, there were about twenty-two thousand responses across thirty-six concentration questions, with incorrect response rates ranging widely but averaging around fifteen percent. The top cosmetic knowledge gaps clustered almost entirely around safety: neurotoxin contraindications and side effects, deoxycholic acid injection side effects, filler rheology, facial vascular anatomy as it relates to filler injection risk, laser and light device tissue reactions, and antibiotic and antiviral prophylaxis around laser procedures. For surgical dermatology, about forty-eight thousand responses across another thirty-six questions, averaging around twelve percent incorrect. The top surgical gaps were signs of typical and atypical postoperative infection, facial nerve anatomy and injury, management of Kaposi sarcoma, prognostic features in Merkel cell carcinoma, ocular emergencies, suture properties, local anesthetic precautions, dermoscopic pattern recognition, indications for preoperative antibiotic prophylaxis, and counseling around hedgehog pathway inhibitors. Both groups, interestingly, converged on an interest in alopecia management.

The authors are appropriately careful about limitations, and there are several worth naming. The gaps identified only reflect the specific question pool approved by ABD committees during this two-year window, not the full universe of practice-relevant topics. Different diplomates receive different proportions of cosmetic versus surgical questions, so exposure wasn't equal across topics, and some genuinely low-performing questions didn't make the top ten list simply because they were tested less often. There's also a real caveat that poor performance on a given question might reflect a badly worded stem or a confusing image rather than a true knowledge deficit, even after validation. And diplomates' choice of which articles or concentration areas to pursue may sometimes be exploratory curiosity rather than a signal of a true clinical practice gap. So take the specific rank ordering with some humility. For your own practice, this is squarely a needs-assessment paper rather than a management-changing one — but it's a legitimate signal of where the broader dermatologic community, including surgically-focused colleagues, tends to underperform: filler and neurotoxin complication recognition, postoperative infection pattern recognition, rarer malignancy prognostics like Merkel cell, and hedgehog inhibitor counseling. If you're involved in resident or fellow education, or building CME content, this table is basically a curriculum blueprint.

Last one is a case series, Myopericytomas: A Rare Entity the Dermatologic Surgeon Should Recognize. Four cases, all in women, which the authors note is actually atypical since myopericytoma more classically occurs in men. Patient one was a seventy-three-year-old woman with a rapidly growing, painful, ulcerated nodule on the dorsal thumb, clinically worrisome for keratoacanthoma or squamous cell carcinoma, that turned out on biopsy to be plump spindle cells positive for smooth muscle actin and negative for desmin — the classic myopericytoma immunoprofile. She went to hand surgery for complete excision and has had no recurrence. Patient two had a tiny, asymptomatic papule on the fifth webspace present for over a decade, biopsied incidentally, showing a small circumscribed spindle cell proliferation with myxoid stroma and focal smooth muscle actin positivity; since margins were clear on the biopsy itself, she's simply being monitored. Patient three is the more concerning case — a fifty-eight-year-old woman with a year of a painful, bleeding, friable exophytic nodule on the heel, two and a half centimeters, removed by surgical oncology, again smooth muscle actin positive and desmin negative, with CD34 and CD31 staining only the surrounding endothelium rather than the tumor cells themselves. Complete excision was recommended, but she was unfortunately lost to follow-up. Patient four is a thirty-three-year-old woman with a small, painful, growing subcutaneous papule on the lateral leg, biopsy-confirmed myopericytoma, with treatment still pending.

The discussion walks through the entity itself: the term was coined back in 1998 by Granter and colleagues, and the World Health Organization places myopericytoma within the broader family of pericytic neoplasms alongside angioleiomyoma and glomus tumor. Pathogenesis is still not well understood — BRAF mutations were once proposed but more recent data don't really support that association, while alterations in PDGFR-beta have been implicated, particularly in patients who present with multiple lesions, a variant called myopericytomatosis. Clinically these tumors are usually solitary, most common on the extremities, especially the lower extremity, though head, neck, and trunk locations occur too, and the clinical appearance is genuinely variable, from a quiet scaly papule to a friable, painful, bleeding plaque, which is exactly why they get misdiagnosed clinically as everything from verruca to dermatofibroma to nonmelanoma skin cancer. Histologically, the giveaway is well-circumscribed nodules of plump, ovoid myoid spindle cells arranged concentrically around vessels — the so-called catherine wheel pattern — and the immunohistochemical signature is smooth muscle actin positive, desmin negative.

There's no formal methods or limitations section here since this is a case series with a focused review, not a designed study, so I won't force that framing on it. What the authors do offer as guidance is management-relevant: surgical excision is the treatment of choice, and while narrow margins have been associated with low recurrence in prior reports, there's no established margin protocol specific to this tumor. Recurrence, when it happens, is generally attributed to incomplete excision, more often an issue with deeper soft tissue lesions. And while the overwhelming majority of these tumors are benign, malignant variants exist and have been associated with metastasis and death, with deeper, multinodular tumors being the ones flagged as higher risk. The practical takeaway for you: keep myopericytoma on the differential for a circumscribed spindle cell lesion on an extremity, especially one with that perivascular concentric growth pattern and an SMA-positive, desmin-negative profile, since that combination helps separate it from other spindle cell mimickers like angioleiomyoma or glomus tumor. Standard management is complete surgical excision, and given the rare but real potential for aggressive behavior in deeper or multinodular lesions, routine postoperative clinical observation is a reasonable standard to build into your follow-up plan, even though there's no data to dictate a specific margin.

That wraps up this month's review. Between the graft-pigmentation case, the global training survey, the ABD's certification data, and the myopericytoma series, the throughline this month is really about pattern recognition — knowing when pigment, spindle cells, or a knowledge gap is telling you something different than it first appears. Thanks for listening, and we'll see you next month.