A pilot study of p53 immunohistochemistry in atypical squamous lesions, using a vulvar scoring system

BACKGROUND

Histopathologic overlap between cutaneous squamous cell carcinoma (cSCC) and its indolent mimics likely leads to the overdiagnosis of cSCC.

OBJECTIVE

To perform a pilot study of the p53 immunohistochemical scoring system developed on vulvar squamous lesions in cSCC.

METHODS

The consistency and reliability of p53 immunostaining using a scoring system developed on vulvar cases, as compared with TP53 genomic sequencing, was studied in an initial cohort of 28 cutaneous cases. p53 labeling was further assessed in an additional 63 cases of atypical squamous lesions, including 20 atypical squamous lesions classified by the authors as benign, 22 cases diagnosed as cSCC without high-risk features, and 21 cases of high-risk cSCC (cSCC-HR).

RESULTS

The concordance of p53 labeling and TP53 sequencing was 82.1%. Four positive patterns of p53 mutation were identified: basal, parabasal/diffuse, null, and cytoplasmic. p53 positivity in atypical, benign squamous lesions (10%) was significantly lower than that of low-risk cSCC (63.6%, p = 0.0004) or cSCC-HR (90.5%, p < 0.0001). p53 positivity in low-risk cSCC versus cSCC-HR was not statistically significant (p = 0.07).

CONCLUSION

p53 Labeling may be a helpful biomarker to support the diagnosis of cSCC and distinguish cSCC from atypical but benign mimics.

Cognitive Bias in the Patient Encounter: Part I. Background and significance

Cognitive bias may lead to diagnostic error in the patient encounter. There are hundreds of different cognitive biases, but certain biases are more likely to affect patient diagnosis and management. As during morbidity and mortality rounds, retrospective evaluation of a given case, with comparison to an optimal diagnosis, can pinpoint errors in judgment and decision-making. The study of cognitive bias also illuminates how we might improve the diagnostic process. In Part 1 of this series, cognitive bias is defined and placed within the background of dual process theory, emotion, heuristics, and the more neutral term judgment and decision-making bias.

Cognitive Bias in the Patient Encounter: Part II. Debiasing using an adaptive toolbox

Cognitive bias may lead to medical error, and awareness of cognitive pitfalls is a potential first step to addressing the negative consequences of cognitive bias (see Part 1). For decision-making processes that occur under uncertainty, which encompass most physician decisions, a so-called "adaptive toolbox" is beneficial for good decisions. The adaptive toolbox is inclusive of broad strategies like cultural humility, emotional intelligence, and self-care that help combat implicit bias, negative consequences of affective bias, and optimize cognition. Additionally, the adaptive toolbox includes situational-specific tools such as heuristics, narratives, cognitive forcing functions, and fast and frugal trees. Such tools may mitigate against errors due to cultural, affective, and cognitive bias. Part 2 of this two-part series covers metacognition and cognitive bias in relation to broad and specific strategies aimed at better decision-making.

Spiny Keratoderma: Clinical and Histopathological Findings in a Series of 3 Cases

ABSTRACT

Spiny keratoderma is a rare entity presenting with minute keratotic spines on the palms and soles. Spiny keratoderma can be inherited or acquired, and the acquired form may be associated with underlying malignancy or systemic disease. Clinically, the differential diagnosis includes other digitate keratoses on acral sites, most notably arsenical keratosis, filiform verruca, and punctate porokeratosis. Biopsy findings typically include a column of parakeratosis overlying a diminished granular cell layer. In this article, we present 3 cases of acquired spiny keratoderma in patients with various systemic diseases, but no underlying malignancy.

Pitfalls of PRAME Immunohistochemistry in a Large Series of Melanocytic and Nonmelanocytic Lesions With Literature Review

ABSTRACT

Preferentially expressed antigen in melanoma (PRAME) immunohistochemistry is currently used to facilitate distinction of benign and malignant melanocytic proliferations. We hypothesized that evaluation of 1 institution's experience with PRAME labeling in a large number of consecutive cases might elucidate additional strengths and potential pitfalls and reveal base rates of positivity versus negativity in 1 academic practice. Pathology reports for all specimens on which PRAME labeling was performed at our institution between January 2021 and May 2022 were retrieved from our database. Eighty percent of conventional malignant melanomas were labeled diffusely positive with PRAME; there were no significant differences in mean age, sex, site, Breslow depth, ulceration status, or American Joint Committee on Cancer pathological tumor stage when comparing diffusely PRAME-positive malignant melanomas with those that lack diffuse labeling. Although no banal melanocytic nevi were labeled with PRAME, 13% of dysplastic nevi were diffusely PRAME positive, with junctional proliferations, severe atypia, male gender, and older age being associated with PRAME positivity. As some but not all ambiguous melanocytic lesions in which malignancy could not be excluded based on morphology alone were diffusely PRAME positive, PRAME's accuracy in predicting malignancy remains unclear to the authors; further study is needed to assess the precision to which PRAME immunohistochemistry can separate benign borderline lesions from their malignant counterparts. Among nonmelanocytic lesions, some poorly differentiated tumors, including atypical fibroxanthomas, can be PRAME positive. This series underscores the importance of clinicopathologic correlation and shows that diffuse PRAME positivity is highest in conventional malignant melanomas (∼80%, or 8 of 10 lesions), is seen in about half of challenging borderline lesions at our institution, and can be observed in lesions diagnosed as dysplastic nevi by our group (∼10% or 1 in 10 lesions), as well as in rare poorly differentiated malignancies.

Cognitive bias in pathology, as exemplified in dermatopathology

Cognitive bias refers to human thinking patterns, as well as pitfalls, that are reproducible. Importantly, cognitive bias is not intentionally discriminatory and is necessary to properly interpret the world around us, including microscopic slides. Thus, it is a useful exercise to examine cognitive bias in pathology, as exemplified in dermatopathology.

Squamous carcinogenesis: potential truncal mutations

Squamous carcinogenesis is incompletely understood, but more recent genetic studies support that the order of acquired mutations is important. This paper will review more recent genetic studies with an emphasis on the potential truncal mutations, mutations critical to the trunk of the cancer evolutionary tree, in actinic keratosis, squamous cell carcinoma in situ, cutaneous squamous cell carcinoma, keratoacanthoma, and keratoacanthoma-like squamous proliferation.

IL17A mRNA Staining Distinguishes Palmoplantar Psoriasis from Hyperkeratotic Palmoplantar Eczema in Diagnostic Skin Biopsies

Acral dermatoses, including hyperkeratotic palmoplantar eczema (HPE), palmoplantar psoriasis (PP), and mycosis fungoides palmaris et plantaris (MFPP), can be challenging to diagnose clinically and histopathologically. In this setting, cytokine biomarkers may be able to help provide diagnostic clarity. Therefore, we evaluated IL-17A, IFN-γ, and IL-13 expression in PP, HPE, and MFPP and compared their expression profiles with nonacral sites. We used biopsy specimens from the Yale Dermatopathology database, selecting cases of HPE (n = 12), PP (n = 8), MFPP (n = 8), normal acral skin (n = 9), nonacral eczema (n = 10), and nonacral psoriasis (n = 10) with classic clinical and histopathologic features. IL17A mRNA expression by RNA in situ hybridization differentiated PP (median score 63.1 [interquartile range 9.4-104.1]) from HPE (0.8 [0-6.0]; P = 0.003), MFPP (0.6 [0-2.6]; P = 0.003), and normal acral skin (0 [0-0]; P < 0.001). Unexpectedly, both PP and HPE showed co-expression of IFNG and IL13 mRNA. In contrast, nonacral psoriasis and eczema showed divergent patterns of IFNG and IL13 mRNA expression. Taken together, we show that IL17A mRNA expression may be a useful biomarker of PP, and we further show that acral dermatoses exhibit distinct immunology compared to nonacral sites, with implications for clinical management.

Vascular-Targeted Therapy for Systemic Lupus Erythematosus-Associated Vasculitis

This case report describes a woman in her 40s with a medical history of systemic lupus erythematosus with 1 year of tender papules, plaques, and progressive ulcers on her hands and feet.

Segmental basaloid follicular hamartomas derive from a post-zygotic SMO p.L412F pathogenic variant and express hair follicle development-related proteins in a pattern that distinguish them from basal cell carcinomas

Basaloid follicular hamartomas (BFH) are benign small basaloid skin tumors that can present as solitary or multiple lesions. Congenital BFH lesions arranged in a segmental distribution have been described, suggesting they derive from a somatic post-zygotic mutational event. Previously, BFH were described in Happle-Tinschert syndrome, which results from a post-zygotic SMO variant and is characterized by segmental BFH with variable involvement of the teeth, skeleton, and central nervous system. Here, we describe two patients with isolated segmental BFH and no systemic involvement. Paired whole exome sequencing of BFH and normal tissue revealed a pathogenic SMO c.1234 C>T, p.L412F variant restricted to BFH tissue. We characterized the proliferation index and expression of Hedgehog and Wnt/beta-catenin pathway related proteins in segmental BFH compared to sporadic basal cell carcinomas (BCCs) and found that segmental BFH had a lower proliferation index. Although segmental BFH expressed a similar level of Gli-1 compared to BCCs, levels of LEF-1 and SOX-9 expression in BFH were weaker for both and patchier for LEF-1. Our results show that a somatic SMO activating variant causes segmental BFH. Since these patients are prone to developing BCCs, differences in SOX9, LEF1, and Ki-67 expression can help distinguish between these two basaloid lesions.

Leukoderma Induced by Rotigotine Patch, a Transdermal Dopamine Agonist

Leukoderma, or hypomelanosis of the skin, can occur in response to various chemical and pharmacologic substances ranging from topical medications to optic preparations and systemic medications. In this case report, we present a 78-year-old man with a history of restless leg syndrome (RLS) who had been using rotigotine transdermal patches once daily for 1 year and developed leukoderma on the bilateral anterior shoulders in the area of patch application. Histopathologic examination showed an absence of melanocytes at the dermal-epidermal junction confirmed by Melan A stain. While the patient was not bothered by the depigmentation and elected to continue the rotigotine patch for his RLS, this case highlights leukoderma as a potential side effect of dopamine transdermal patches and offers insight into the potential mechanism of hypopigmentation in response to dopamine agonism.

Neutrophilic Dermatoses: a Clinical Update

Purpose of Review

Neutrophilic dermatoses are defined by the presence of a sterile neutrophilic infiltrate on histopathology. This review focuses on the pathogenesis, epidemiology, clinicopathological features, diagnosis, and management of four disorders: Sweet syndrome, pyoderma gangrenosum, Behçet syndrome, and neutrophilic eccrine hidradenitis.

Recent Findings

Recent studies have provided insight into the complex pathogenesis of neutrophilic dermatoses. Evidence supports an intricate interplay of abnormal neutrophil function and inflammasome activation, malignant transformation into dermal infiltrating neutrophils, and genetic predisposition.

Summary

Neutrophilic dermatoses have diverse cutaneous and extracutaneous manifestations and may be associated with significant morbidity and mortality. Common underlying associations include infectious, inflammatory, and neoplastic disorders, as well as drug reactions. Emerging diagnostic and therapeutic frameworks identify an expanding role for biologic and targeted anti-inflammatory therapies.

Erratum: Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation

[This corrects the article DOI: 10.1016/j.xhgg.2021.100028.].

Post-COVID-19 vaccination IgA vasculitis in an adult

Leukocytoclastic vasculitis has been reported in the setting of COVID‐19 infection and post‐COVID‐19 vaccination. We report a case of IgA vasculitis (IgAV) post‐COVID‐19 vaccination, with immunoglobulin A (IgA) immune deposits in the skin and renal involvement. SARS‐CoV spike protein immunohistochemical staining was negative. IgAV with skin and renal involvement is a potential reaction to COVID‐19 vaccination.

Relationship-Centered Care in the Physician-Patient Interaction: Improving Your Understanding of Metacognitive Interventions

The concept of relationship-centered care was first introduced approximately 20 years ago, but this important concept has not yet been widely disseminated in clinical practice. Relationship-centered care in the health profession focuses on all relevant relationships in health care, not only between health care professionals and patients but also among colleagues, staff members, students, community, and self. This review summarizes the key literature to date on relationship-centered care as it pertains to the physician-patient relationship. Becoming more aware of the physician (self) and patient is a form of metacognition, thinking about what is happening in the moment as physicians and patients come together. Considering the complexity of the physician-patient relationship, we can implement simple metacognitive techniques toward the daily habitual practice of relationship-centered care.

Cytokine RNA In Situ Hybridization Permits Individualized Molecular Phenotyping in Biopsies of Psoriasis and Atopic Dermatitis

Detection of individual cytokines in routine biopsies from patients with inflammatory skin diseases has the potential to personalize diagnosis and treatment selection, but this approach has been limited by technical feasibility. We evaluate whether a chromogen-based RNA in situ hybridization approach can be used to detect druggable cytokines in psoriasis and atopic dermatitis. A series of psoriasis (n = 20) and atopic dermatitis (n = 26) biopsies were stained using RNA in situ hybridization for IL4, IL12B (IL-12/23 p40), IL13, IL17A, IL17F, IL22, IL23A (IL-23 p19), IL31, and TNF (TNF-α). NOS2 and IFNG, canonical psoriasis biomarkers, were also included. All 20 of the psoriasis cases were positive for IL17A, which tended to be the predominant cytokine, although some cases had relatively higher levels of IL12B, IL17F, or IL23A. The majority of cytokine expression in psoriasis was epidermal. A total of 22 of 26 atopic dermatitis cases were positive for IL13, also at varying levels; a subset of cases had significant IL4, IL22, or IL31 expression. Patterns were validated in independent bulk RNA-sequencing and single-cell RNA-sequencing datasets. Overall, RNA in situ hybridization for cytokines appears highly specific with virtually no background staining and may allow for individualized evaluation of treatment-relevant cytokine targets in biopsies from patients with inflammatory skin disorders.

Leukocytoclastic Vasculitis and Microvascular Occlusion: Key Concepts for the Working Pathologist

Although clinicians often put vasculitis and microvascular occlusion in the same differential diagnosis, biopsy findings often are either vasculitis or occlusion. However, both vasculitis and occlusion are present in some cases of levamisole-associated vasculopathy and certain infections. Depth of dermal involvement and vessel size should be reported, because superficial and deep small vessel leukocytoclastic vasculitis and/or involvement of medium-sized vessels may be associated with systemic disease. Microvascular occlusion of vessels in the fat should prompt consideration of calciphylaxis. Clues to ultimate clinical diagnosis can be garnered from depth of involvement, size of vessels affected, and presence of both vasculitis and occlusion.

Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation

The term “cavernous hemangioma” has been used to describe vascular anomalies with histology featuring dilated vascular spaces, vessel walls consisting mainly of fibrous stromal bands lined by a layer of flattened endothelial cells, and an irregular outer rim of interrupted smooth muscle cells. Hepatic hemangiomas (HHs) and cutaneous venous malformations (VMs) share this histologic pattern, and we examined lesions in both tissues to identify genetic drivers. Paired whole-exome sequencing (WES) of lesional tissue and normal liver in HH subjects revealed a recurrent GJA4 c.121G>T (p.Gly41Cys) somatic mutation in four of five unrelated individuals, and targeted sequencing in paired tissue from 9 additional HH individuals identified the same mutation in 8. In cutaneous lesions, paired targeted sequencing in 5 VMs and normal epidermis found the same GJA4 c.121G>T (p.Gly41Cys) somatic mutation in three. GJA4 encodes gap junction protein alpha 4, also called connexin 37 (Cx37), and the p.Gly41Cys mutation falls within the first transmembrane domain at a residue highly conserved among vertebrates. We interrogated the impact of the Cx37 mutant via lentiviral transduction of primary human endothelial cells. We found that the mutant induced changes in cell morphology and activated serum/glucocorticoid-regulated kinase 1 (SGK1), a serine/threonine kinase known to regulate cell proliferation and apoptosis, via non-canonical activation. Treatment with spironolactone, an inhibitor of angiogenesis, suppressed mutant SGK1 activation and reversed changes in cell morphology. These findings identify a recurrent somatic GJA4 c.121G>T mutation as a driver of hepatic and cutaneous VMs, revealing a new pathway for vascular anomalies, with spironolactone a potential pathogenesis-based therapy.

Cutaneous Involvement in Plasma Cell Myeloma

OBJECTIVES

Plasma cell myeloma (PCM) involving skin is rare and occurs in 1% to 4% of patients with PCM. We evaluated the clinicopathologic features, cytogenetic findings and clinical follow-up in a series of PCM cases with cutaneous involvement.

METHODS

Cases of PCM with cutaneous involvement were retrospectively reviewed with clinical data.

RESULTS

Skin involvement in PCM occurred in older individuals (mean, 75 years) and was more frequent in men (7/10 patients). All cases showed bone marrow involvement preceding the cutaneous lesions. Histopathologically, the infiltrate was plasmacytic (n = 5) or primitive or plasmablastic (n = 4), and 1 case showed predominantly lymphoplasmacytic features with cyclin D1 immunoreactivity and CCND1 gene rearrangement. Concurrent amyloid deposition was seen in one biopsy, and another case demonstrated coexisting squamous cell carcinoma. The most common immunophenotype was CD138+, CD20-, and CD56+ with light chain restriction. Cytogenetic analysis (available for 7 cases) showed multiple hyperdiploid abnormalities. Follow-up was available for 8 cases (mean, 42 months; range, 11-156 months) and showed short-term disease-related death in 7 of 8 patients.

CONCLUSIONS

Cutaneous involvement in PCM demonstrates a diverse cytomorphologic spectrum with plasmacytic, plasmablastic, or lymphoplasmacytic features and may show concurrent amyloid deposition or neoplasms such as squamous cell carcinoma. Cutaneous involvement typically occurs late in the course of the disease and likely portends poor outcome.

Response to Tembhre et al.: 'Enhanced expression of angiotensin-converting enzyme 2 in psoriatic skin and its upregulation in keratinocytes by interferon-γ: implication of inflammatory milieu in skin tropism of SARS-CoV-2'

Linked Article: Tembhre et al. Br J Dermatol 2021; 184:577–579.

Discordant anti-SARS-CoV-2 spike protein and RNA staining in cutaneous perniotic lesions suggests endothelial deposition of cleaved spike protein

BACKGROUND

Prior studies have shown the presence of immunohistochemical staining for the SARS-CoV-2 spike protein (SP) in endothelial cells and eccrine epithelium of acral perniosis classified as "COVID toes." Yet, other studies have been unable to detect SARS-CoV-2 RNA in skin biopsies of "COVID toes" by reverse-transcriptase polymerase chain reaction testing.

OBJECTIVE

In order to address these apparently conflicting findings, we compared detection of SARS-CoV-2 SP, through RNA in situ hybridization (ISH) vs immunohistochemistry (IHC), in skin biopsies of acral perniotic lesions presenting during the COVID-19 pandemic.

RESULTS

Three of six cases showed positive immunohistochemical labeling of endothelial cells, with one of three cases with sufficient depth also having labeling of eccrine glands, using an anti-SP SARS-CoV-2 antibody. These three cases positive with IHC were negative for SP by RNA ISH.

CONCLUSION

While the gold standard for detection of SARS-CoV-2 in tissue sections has yet to be determined, the detection of SARS-CoV-2 SP alone without spike RNA suggests that cleaved SP may be present in cutaneous endothelial cells and eccrine epithelium, providing a potential pathogenetic mechanism of COVID-19 endotheliitis.

Perniosis during the COVID-19 pandemic: Negative anti-SARS-CoV-2 immunohistochemistry in six patients and comparison to perniosis before the emergence of SARS-CoV-2

BACKGROUND

Acral inflammatory lesions that have some resemblance to idiopathic or autoimmune-associated perniosis (chilblains) have been described in multiple countries during the COVID-19 pandemic.

METHODS

We examined histopathologic findings in six consecutive such cases from five patients received in mid-May to mid-June of 2020, evaluating immunohistochemical staining for the SARS-CoV-2 nucleocapsid protein. We compared these six cases to eight cases diagnosed as perniosis between January and June of 2019.

RESULTS

Five of six lesions with perniosis-like histopathology during the COVID-19 pandemic had distinctive tight cuffing of lymphocytes; intravascular material was present in one case. SARS-CoV-2 immunohistochemical staining using an antibody directed at the nucleocapsid protein was negative in all six cases. Only one of eight specimens with microscopic findings of perniosis received prior to the COVID-19 pandemic had tightly cuffed perivascular lymphocytes, and none had obvious intravascular occlusion.

CONCLUSIONS

A tightly cuffed pattern of perivascular lymphocytes is a feature of perniosis during the COVID-19 pandemic. The absence of SARS-CoV-2 nucleocapsid protein in these cases suggests against the virus being directly present in these lesions.

A detailed analysis of the distribution, morphology, and histopathology of complex purpura in hospitalized patients: A case series of 68 patients

BACKGROUND

Purpura in inpatients commonly leads to dermatologic consultation. The differential diagnosis is broad and algorithms are intricate.

OBJECTIVE

We evaluated inpatient consultations for complex purpura to document the most common diagnoses and to validate the true diagnostic utility of histopathology, clinical morphology, and distribution.

METHODS

We reviewed a case series of 68 inpatients during a 4-year period with a dermatologic consultation for purpura and biopsy findings of vasculitis or microvascular occlusion.

RESULTS

Key features of complex purpura are nonbranching (round) versus branching (retiform) morphology, dependent versus acral or generalized distribution, and leukocytoclastic vasculitis versus microvascular occlusion (with emphasis on depth of involvement). Dependent nonbranching purpura with only superficial vessels involved by leukocytoclastic vasculitis was most often due to IgA vasculitis or cutaneous single-organ small-vessel vasculitis. In contrast, deeper involvement by leukocytoclastic vasculitis was suggestive of systemic disease (eg, antineutrophil cytoplasmic antibody-associated vasculitis). Branching purpura was concerning, with greater than 90% sensitivity and specificity for microvascular occlusion and associated high mortality (≈50%). The majority of patients who died had acral branching lesions.

LIMITATIONS

Small sample size, inpatients at a tertiary care center, and retrospective nature are some limitations.

CONCLUSION

Nonbranching dependent purpura corresponded to leukocytoclastic vasculitis, with the most common diagnoses being IgA vasculitis or skin-limited small-vessel vasculitis; patients with deep involvement often had systemic diseases. In this series, branching purpura was due to microvascular occlusion rather than medium-vessel vasculitis, and had associated high mortality.

Diltiazem-associated Photodistributed Hyperpigmentation

Diltiazem is a calcium-channel blocker commonly used for the treatment of hypertension. Common adverse effects include dizziness, headache, and edema. Fewer than 20 cases of diltiazem-associated photodistributed hyperpigmentation have been reported in the literature. Here, we present the case of a 71-year-old woman with new-onset facial hyperpigmentation 6 months after initiating treatment with diltiazem.

Intravascular Large B-Cell Lymphoma: Clinical and Histopathologic Findings

Intravascular large B-cell lymphoma (IVLBCL) is a rare subset of extranodal non-Hodgkin lymphoma characterized by neoplastic lymphocytes within the lumina of small to medium-sized blood vessels. IVLBCLs are B-cell tumors that can present in essentially any organ system, including the skin. Cutaneous manifestations vary greatly and can mimic other skin disease which may delay diagnosis; in the absence of skin lesions, blind skin biopsies can be utilized for diagnosis. Early studies suggested that IVLBCL is a very aggressive lymphoma with high overall mortality rate and short survival times. However, earlier diagnosis and use of new treatment modalities have shown promise in recent studies. This case series illustrates the heterogeneity of clinical and pathologic presentations of this uncommon lymphoma.

Second-Hit, Postzygotic PMVK and MVD Mutations in Linear Porokeratosis

Importance

Linear porokeratosis features linear and whorled configurations of keratotic papules and plaques, with coronoid lamellae present on histologic examination. Because linear porokeratosis manifests in the lines of Blaschko representing the dorsoventral migration patterns of keratinocyte precursors, it has been suggested that postzygotic somatic mutation underlies the disease. However, no genetic evidence has supported this hypothesis to date.

Objective

To identify genetic mutations associated with linear porokeratosis.

Design, Setting, and Participants

Paired whole-exome sequencing of affected skin and blood/saliva samples from 3 participants from 3 academic medical centers with clinical and histologic diagnoses of linear porokeratosis.

Interventions or Exposures

Whole-exome sequencing of paired blood/saliva and affected tissue samples isolated from linear porokeratosis lesions.

Main Outcomes and Measures

Germline and somatic genomic characteristics of participants with linear porokeratosis.

Results

Of the 3 participants, 2 were male. Participant ages ranged from 5 to 20 years old. We found a combination of a novel germline mutation and a novel somatic mutation within affected tissue in all cases. One participant had a germline heterozygous PMVK c.329G>A mutation and a somatic copy-neutral loss of heterozygosity confined to the lesional skin, while a second had a germline heterozygous PMVK c.79G>T mutation and an additional PMVK c.379C>T mutation in the lesional skin. In a third participant, there was a germline splice-site mutation in MVD (c.70 + 5G>A) and a somatic deletion in MVD causing frameshift and premature codon termination within the lesional skin (c.811_815del, p.F271Afs*33 frameshift).

Conclusions and Relevance

Our findings suggest that linear porokeratosis is associated with the presence of second-hit postzygotic mutations in the genes that encode enzymes within the mevalonate biosynthesis pathway, and provide further evidence that the mevalonate pathway may be a potential target for therapeutic intervention in porokeratosis.

Histopathologic findings characteristic of CARD14-associated papulosquamous eruption

BACKGROUND

Pathogenic mutations in caspase recruitment domain-containing protein 14 (CARD14) lead to CARD14-associated papulosquamous eruption, which shares clinicopathologic findings with psoriasis and pityriasis rubra pilaris. We aimed to describe distinguishing histopathologic features of CARD14-associated papulosquamous eruption.

METHODS

This retrospective study examined the histopathologic features of specimens from patients with confirmed CARD14-associated papulosquamous eruption and adult patients with plaque psoriasis and pityriasis rubra pilaris.

RESULTS

Lesional skin biopsies from patients with CARD14-associated papulosquamous eruption consistently showed alternating checkerboard parakeratosis and orthokeratosis, acanthosis without acantholysis, and dilated vessels in the dermal papillae, with some cases also showing follicular plugging.

CONCLUSION

CARD14-associated papulosquamous eruption has a range of findings, with a predominance of features typically associated with pityriasis rubra pilaris.

Hypergranulotic dyscornification: 30 cases of a striking epithelial reaction pattern

BACKGROUND

Hypergranulotic dyscornification (HD) is a rarely reported histological reaction pattern that may be observed in solitary benign keratoses.

OBJECTIVE AND METHODS

We retrospectively reviewed all cases described as displaying "hypergranulotic dyscornification" at our institution between January 1st 1990 to September 1st 2018. We excluded cases that on retrospective review displayed changes of epidermolytic hyperkeratosis. We conducted electron microscopy (EM) of two lesions.

RESULTS

Thirty cases were identified in our search. Eleven patients were men and 19 were women. Their mean age was 56.9 ± 21.2 years. In contrast to previous reports, we found that HD does not spare the head and neck area. Frequent clinical impressions were inflamed seborrheic keratosis, Bowen disease or inflamed verruca. The most distinctive histopathologic finding was the presence of a prominent granular layer with clumped perinuclear keratohyaline granules. Some cases had mounds of rounded, anucleate glassy eosinophilic corneocytes in the stratum corneum. We observed one case of incidental HD occurring in an epidermoid cyst. EM of HD showed dense perinuclear bands which appeared to match areas of positive staining by keratin immunohistochemistry, without evidence of pale cytoplasmic areas devoid of keratin filaments, characteristic of epidermolytic hyperkeratosis.

CONCLUSION

HD is a reproducible finding in some benign keratoses, probably because of abnormal keratinization. Awareness of this unique reaction pattern will help prevent misdiagnosis.

Cutaneous Squamous Cell Carcinomas in Solid Organ Transplant Recipients Compared With Immunocompetent Patients

Importance

Solid organ transplant recipients (SOTRs) have a 100-fold increased risk of squamous cell carcinoma (SCC), and they may develop more aggressive SCCs compared with immunocompetent individuals.

Objective

To compare outcomes associated with aggressive behavior of SCC in SOTRs and high-risk immunocompetent patients.

Design, Setting, and Participants

A retrospective cohort study of 58 SOTRs and 40 immunocompetent patients evaluated at the Yale Transplant Dermatology Clinic in New Haven, Connecticut, who had at least 1 SCC confirmed histopathologically between January 1, 2008, and December 31, 2015. Cumulative follow-up time for this study was 369 patient-years.

Exposure

Immunosuppressive medication regimen for SOTRs.

Main Outcomes and Measures

The primary outcome measure was tumor depth of SCC. Secondary outcome measures that reflected tumor aggressiveness included perineural invasion, regional metastases, nodal metastases, disease-specific death, and overall death.

Results

Of the 58 SOTR study participants, 14 were women and 44 were men; the mean (SD) age was 61.3 (8.4) years. Of the 40 immunocompetent study participants, 16 were women and 24 were men; the mean (SD) age was 69.8 (10.9) years, resulting in a statistically significant difference from the SOTR group. The mean (SD) number of years that SOTRs were immunosuppressed was 14.6 (9.2) years (range, 2-37 years). The SOTR and immunocompetent groups were statistically comparable regarding race and sex, patient care, follow-up time, numbers of skin lesions, and field cancerization and chemopreventive therapies. The SOTR group had a significantly higher annual frequency of visits (mean [SD], 4 [2] vs 3 [2] office visits per patient per year, P = .02) and annual biopsy rates (mean [SD], 6 [4] vs 5 [3] biopsies per patient per year, P = .04). The SOTRs developed SCCs that did not appear to be significantly more aggressive than those found in the immunocompetent control group. These SOTRs also did not develop significantly thicker tumors than the immunocompetent control group (median [IQR] tumor depth, 1.30 [0.90-1.60] mm in 35 SOTRs vs 1.22 [1.10-1.60] mm in 20 immunocompetent patients).

Conclusions and Relevance

The increased risk and the potential for aggressive behavior of SCCs in SOTRs may be successfully managed at a level comparable to that in high-risk immunocompetent individuals through close adherence to current dermatologic surveillance recommendations and a marginally lower threshold for biopsy of suspicious lesions for SOTRs.

Coccygeal Polypoid Eccrine Nevus

Skin tags are fairly common lesions usually seen in adults on the neck and in body folds. The sacrococcygeal region is an unusual location for skin tags in children and may represent a congenital malformation of the spine or an isolated skin lesion. In this review, we summarize the clinical presentation, histopathologic changes, and differential diagnosis of coccygeal polypoid eccrine nevus as a rare cause of sacrococcygeal papules in children.

Cutaneous immunohistochemical staining pattern of p53β isoforms

p53 is considered the guardian of the genome and as such has numerous functions. The TP53 gene is the most commonly mutated gene in cancer, and yet the exact biological significance of such mutations remains unclear. There are at least 12 different isoforms of p53, and the complexity of the p53 pathway may be in part related to these isoforms. Prior research has often not teased out what isoforms of p53 are being studied, and there is evidence in the literature that p53 isoforms are expressed differently. In this paper, we document the staining pattern of p53β isoforms in the skin and correlate it with mutational status in a subgroup of squamous proliferations of the skin. p53β isoforms are present in the cytoplasm of the differentiated layer of the epidermis and hair follicles (granular layer, infundibular and isthmus-catagen). p53β isoforms are diffusely expressed within the cytoplasm of well-differentiated squamous tumours with tetramerisation (C-terminal) domain mutations in TP53 Our results lend support to p53β isoforms being a marker of differentiation in keratinocytes.

Well-differentiated neuroendocrine tumors in skin: Terminology and diagnostic utility of cytokeratin 5/6 and p63

BACKGROUND

Well-differentiated neuroendocrine tumors (WDNETs) in skin include metastases from visceral primary sites and very uncommonly, primary cutaneous carcinoid tumors. Cutaneous WDNET may present a diagnostic challenge and in particular can be mistaken for a benign skin adnexal tumor. In contrast to cutaneous adnexal tumors, metastatic adenocarcinomas to the skin are cytokeratin 5/6 (CK5/6) and p63 negative in the majority of cases. It is unclear if failure to stain with CK5/6 and p63 would be helpful in differentiating WDNETs from cutaneous adnexal neoplasms.

METHODS

We reviewed 10 cases of cutaneous WDNETs (8 cases of metastatic disease and 2 presumed primary carcinoid tumors of the skin) and performed immunohistochemical stains for CK5/6 and p63 on all cases.

RESULTS

All 10 cases were negative with both CK5/6 and p63.

CONCLUSION

Negative staining for CK5/6 and p63 can be helpful to distinguish WDNETs from cutaneous adnexal neoplasms. It is important to consider WDNETs in the differential diagnosis of cutaneous adnexal neoplasms as low-grade tumors may be the first sign of aggressive metastatic disease.

Predicting non-melanoma skin cancer via a multi-parameterized artificial neural network

Ultraviolet radiation (UVR) exposure and family history are major associated risk factors for the development of non-melanoma skin cancer (NMSC). The objective of this study was to develop and validate a multi-parameterized artificial neural network based on available personal health information for early detection of NMSC with high sensitivity and specificity, even in the absence of known UVR exposure and family history. The 1997-2015 NHIS adult survey data used to train and validate our neural network (NN) comprised of 2,056 NMSC and 460,574 non-cancer cases. We extracted 13 parameters for our NN: gender, age, BMI, diabetic status, smoking status, emphysema, asthma, race, Hispanic ethnicity, hypertension, heart diseases, vigorous exercise habits, and history of stroke. This study yielded an area under the ROC curve of 0.81 and 0.81 for training and validation, respectively. Our results (training sensitivity 88.5% and specificity 62.2%, validation sensitivity 86.2% and specificity 62.7%) were comparable to a previous study of basal and squamous cell carcinoma prediction that also included UVR exposure and family history information. These results indicate that our NN is robust enough to make predictions, suggesting that we have identified novel associations and potential predictive parameters of NMSC.

Dermatomyositis: Histopathologic findings of parakeratosis and dermal edema revisited

The cutaneous manifestations of dermatomyositis range from classical in the case of heliotrope rash and Gottron papules to less common papulosquamous and edematous/vesiculobullous lesions; histopathologic descriptions are dominated by interface dermatitis. We present a case of dermatomyositis with a combination of common and rare skin findings, both clinically and histologically. Increased awareness of papulosquamous and edematous lesions of dermatomyositis can help direct patient care. Although uncommon, confluent parakeratosis and dermal edema can be manifestations of dermatomyositis.

Metastatic serous carcinoma presenting as inflammatory carcinoma over the breast-Report of two cases and literature review

Non-mammary metastases involving breast are rare and most commonly involve the breast parenchyma. Infrequently, metastasis from an extramammary primary site presents as inflammatory carcinoma over the breast. Diagnosis of such lesions can be challenging, especially in patients with coexisting primary breast carcinoma. Few such cases have been described in literature; however, none of the previously reported cases had a prior history of primary breast carcinoma. We present 2 patients with history of breast carcinoma and serous carcinoma of ovarian/peritoneal origin that presented with inflammatory carcinoma over the breast. Biopsies from breast tissue showed atypical cells in the dermis forming cords and papillary structures. Histopathologic differential diagnosis included infiltrating ductal carcinoma of breast origin and metastatic serous carcinoma. Immunohistochemical studies showed that the tumor cells were positive for markers of ovarian origin such as PAX-8 and CA-125 and negative for breast markers such as GATA-3, thus supporting the diagnosis. In summary, we describe the unusual presentation of metastatic serous carcinoma as inflammatory carcinoma over breast and discuss the diagnostic challenges in patients with coexisting primary breast and ovarian malignancies. We also review the morphologic features of tumors of breast and ovarian origin and the immunohistochemical stains to differentiate these 2 entities.

Rapidly increasing liver progenitor cell numbers in human regenerating liver after portal vein ligation and liver partition

BACKGROUND

Liver regeneration is dependent on the proliferation of hepatocytes. Hepatic progenitor cells are intra-hepatic precursor cells capable of differentiating into hepatocytes or biliary cells. Although liver progenitor cell proliferation during the regenerative process has been observed in animal models of severe liver injury, it has never been observed in vivo in humans because it is unethical to take multiple biopsy specimens for the purpose of studying the proliferation of liver progenitor cells and the roles they play in liver regeneration. Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a staged procedure for inducing remnant liver hypertrophy so that major hepatectomy can be performed safely. This staged procedure allows for liver biopsy specimens to be taken before and after the liver begins to regenerate.

CASE PRESENTATION

The liver progenitor cell proliferation is observed in a patient undergoing ALPPS for a metastatic hepatic tumour. Liver biopsy is acquired before and after ALPPS for the calculation of average number of liver progenitor cell under high magnification examination by stain of immunomarkers. This is the first in vivo evidence of growing liver progenitor cells demonstrated in a regenerating human liver.