This month's news from across the specialty

January 1, 2022

In this monthly column, members of the DermWorld Editorial Advisory Workgroup identify exciting news from across the specialty.  

Diagnostic conundrums are often presented at dermatology teaching conferences in which the presenter asks the audience for a differential diagnosis. After the audience fails to come up with the “correct” diagnosis, despite an exhaustive list, the presenter reveals the “correct” diagnosis. Often, this is an exceedingly rare entity (“only X number of cases ever reported,” or “I found a case report of this,” or “this is a rare presentation of this extremely rare disease”). The audience members then leave the conference with the excitement of thinking they just saw a platypus, when, in reality, it was just a duck. This scenario is rampant: diagnosing a zebra and ignoring the horse galloping in plain sight.

What are the cognitive errors that lead to favoring a rare (and oftentimes erroneous) diagnosis over the more common or likely one? One source of error is base rate neglect — ignoring the probability of seeing a certain disease. Are we really that lucky to be seeing a platypus? A second potential source of error is overconfidence bias — the unjustified faith in the reliability of one’s knowledge, skills, or judgment. Frequently, dermatologists place excessive confidence in the pathology report, describing disorders as “biopsy-proven,” when accurate diagnosis depends on clinicopathologic correlation and follow up.

We need to minimize mistakes that result from cognitive bias. Patients entrust themselves to our care and presume that we are knowledgeable and experienced enough to overcome common sources of diagnostic error. Our patients look to us for something that (at least for the present) computers, algorithms, and checklists cannot replace: our judgment (AJOG. 2020; 222(5): 469-70).

There’s room for improvement. The dermatologist and dermatopathologist have a close relationship in the goal of good patient care. Smith et al eloquently remind us of this in their recent JAMA Derm viewpoint article (2021. 157(9):1033-4). Specifically, they highlight the importance of providing accurate clinical information when submitting biopsy specimens to the pathology laboratory. While electronic medical records have increased efficiency for some, it has led to the use of “stock” clinical descriptions and diagnoses that can be misleading. Additionally, some electronic health record systems save pull-down descriptions and differentials that carry forward to the next patient pathology requisition. For example, on one day, our laboratory received three biopsies from three different patients from the same clinician stating that the patient had sarcoidosis. While this may be true, it is likely due to the electronic record forwarding the information to the next patient. This type of issue can lead to unnecessary special stains and delay of the pathology report. It is also important to remember that many benign entities can mimic malignancy and vice versa. This is highlighted in a recent case report of lichen aureus with pseudolymphomatous infiltrate (J Cutan Pathol. 2020. 48:669-73). This report reminds us that benign entities such as pigmented purpura may have an infiltrate that resembles cutaneous lymphoma. In this case, the clinical diagnosis and description are of paramount importance. With the recent implementation of the Cures Act Final Rule, and patients having immediate access to their reports, one can imagine the consequences of getting a pathology report of cutaneous lymphoma in someone who has lichen aureus. There will always be a little room for improvement, and we should continue to work together for the best patient outcomes.

Topical ruxolitinib, a Janus kinase (JAK) inhibitor, is now FDA-approved for the treatment of atopic dermatitis. Ruxolitinib selectively inhibits JAK1 and JAK2, which mediate signaling for both hematopoiesis and immune function. JAK signaling is thought to be linked to the inflammation, pruritus, and barrier disruption in atopic dermatitis.

The medication is applied to affected areas twice daily, and per label recommendations, is intended for patients with <20% BSA. The efficacy of topical ruxolitinib is demonstrated in two randomized clinical trials which enrolled over 1,200 patients with mild-to-moderate atopic dermatitis (<20% BSA affected) not controlled by previous prescription topicals. More individuals in the ruxolitinib group achieved clear or almost clear skin, as well as reduced pruritus, as compared to vehicle. There were no significant adverse events or side effects of the medication. Systemic absorption appears to be minimal. There are no contraindications on the manufacturer’s label (J Am Acad Dermatol. 2021;85(4): 863). Of note, topical ruxolitinib is also being used as off-label treatment for both vitiligo and alopecia areata.

Rates of anal cancer and anal-cancer mortality have been rising for years. In the United States in 2021, according to American Cancer Society (ACS) estimates, 9,090 new cases and 1,430 deaths from anal cancer will occur, mostly among women. Risk factors include oncogenic-type human papillomavirus (HPV) infection; anal warts; cervical, vaginal, or vulvar cancer; HIV infection; having multiple sex partners; engaging in receptive anal sex; smoking; and immunosuppression. White women and Black men are more commonly affected.

It’s also been known for years that anal-cancer screening, with cytology followed by anoscopy, can identify precancerous lesions. What hasn’t been known is whether that screening improves outcomes. Screening is recommended and done at certain institutions, but the Centers for Disease Control and Prevention (CDC), citing insufficient data, has not recommended it, although it suggests screening by digital anorectal exam for some individuals.

But it now looks like data indeed show that anal-cancer screening works. In October 2021, the Anal Cancer/HSIL Outcomes Research (ANCHOR) study was halted early, after interim results showed that, compared with observation, treatment of high-grade squamous intraepithelial lesions (HSIL) reduced progression to anal cancer.

While results are being prepared for publication in a peer-reviewed journal, the ANCHOR investigators summarized the findings, citing their public-health importance, in a press release.

These results might lead CDC and other organizations to recommend anal-cancer screening for certain individuals. (HPV vaccination, effective against certain oncogenic HPV types and routinely recommended, likely also reduces anal-cancer risk.) Recommendations regarding anal-cancer screening (like those for HPV vaccination) will likely apply to many patients seen in general dermatology practices.

Additional DermWorld Resources