Appropriate use criteria for ancillary diagnostic testing in dermatopathology: New recommendations for 11 tests and 220 clinical scenarios from the American Society of Dermatopathology Appropriate Use Criteria Committee.

BACKGROUND: Appropriate use criteria (AUC) provide patient-centered physician guidance in test selection. An initial set of AUC was reported by the American Society of Dermatopathology (ASDP) in 2018. AUC reflect evidence collected at single timepoints and may be affected by evolving evidence and experience. The objective of this study was to update and expand AUC for selected tests. METHODS: RAND/UCLA (RAND Corporation [Santa Monica, CA]/University of California Los Angeles) methodology used includes the following: (a) literature review; (b) review of previously rated tests and previously employed clinical scenarios; (c) selection of previously rated tests for new ratings; (d) development of new clinical scenarios; (e) selection of additional tests; (f) three rating rounds with feedback and group discussion after rounds 1 and 2. RESULTS: For 220 clinical scenarios comprising lymphoproliferative (light chain clonality), melanocytic (comparative genomic hybridization, fluorescence in situ hybridization, reverse transcription polymerase chain reaction, telomerase reverse transcriptase promoter), vascular disorders (MYC), and inflammatory dermatoses (periodic acid-Schiff, Gömöri methenamine silver), consensus by panel raters was reached in 172 of 220 (78%) scenarios, with 103 of 148 (70%) rated "usually appropriate" or "rarely appropriate" and 45 of 148 (30%), "appropriateness uncertain." LIMITATIONS: The study design only measures appropriateness. Cost, availability, test comparison, and additional clinical considerations are not measured. The possibility that the findings of this study may be influenced by the inherent biases of the dermatopathologists involved in the study cannot be excluded. CONCLUSIONS: AUC are reported for selected diagnostic tests in clinical scenarios that occur in dermatopathology practice. Adhering to AUC may reduce inappropriate test utilization and improve healthcare delivery.

Cutaneous intestinal metaplasia: An unusual cause of peristomal complication with malignant potential.

Peristomal ulcer with cutaneous intestinal metaplasia, defined by scattered colonic crypts within variably intact epidermis, is an exceedingly rare pathologic diagnosis, which possesses the potential to progress to primary adenocarcinoma. Herein, we report the third case of cutaneous intestinal metaplasia in a peristomal ulcer and emphasize the importance of diagnosis and surveillance when managing this rare entity.

TERT and TERT promoter in melanocytic neoplasms: Current concepts in pathogenesis, diagnosis, and prognosis.

BACKGROUND AND OBJECTIVE: Located on chromosome locus 5p15.33, telomerase reverse transcriptase (TERT or hTERT) encodes the catalytic subunit of telomerase which permits lengthening and preservation of telomeres following mitosis. Mutations in TERT promoter (TERT-p) upregulate expression of TERT, allowing survival of malignant cells and tumor progression in wide variety of malignancies including melanoma. The objective of this review is to examine the roles of TERT and TERT-p in the pathogenesis, diagnosis, and prognostication of cutaneous melanoma. METHODS: All studies of TERT or TERT-p in cutaneous melanocytic neoplasms with the following inclusion criteria were reviewed: publication date between 2010 and 2019, English language, and series of ≥3 cases were reviewed for evidence supporting the role of TERT in pathogenesis, diagnosis, and prognosis. Studies with <3 cases or focused primarily on mucosal or uveal melanocytic tumors were excluded. RESULTS AND CONCLUSION: TERT-p mutations are frequent in chronic and non-chronic sun damage melanoma and correlate with adverse prognosis, inform pathogenesis, and may provide diagnostic support. While TERT-p mutations are uncommon in acral melanoma, TERT copy number gains and gene amplification predict reduced survival. Among atypical spitzoid neoplasms, TERT-p mutations identify biologically aggressive tumors and support the diagnosis of spitzoid melanoma. TERT-p methylation may have prognostic value in pediatric conventional melanoma and drive tumorigenesis in melanoma arising within congenital nevi. Finally, TERT-p mutations may aid in the differentiation of recurrent nevi from recurrent melanoma.

Appropriate use criteria in dermatopathology: Initial recommendations from the American Society of Dermatopathology.

BACKGROUND: Appropriate use criteria (AUC) provide physicians guidance in test selection, and can affect health care delivery, reimbursement policy, and physician decision-making. OBJECTIVES: The American Society of Dermatopathology, with input from the American Academy of Dermatology and the College of American Pathologists, sought to develop AUC in dermatopathology. METHODS: The RAND/UCLA appropriateness methodology, which combines evidence-based medicine, clinical experience, and expert judgment, was used to develop AUC in dermatopathology. RESULTS: With the number of ratings predetermined at 3, AUC were developed for 211 clinical scenarios involving 12 ancillary studies. Consensus was reached for 188 (89%) clinical scenarios, with 93 (44%) considered "usually appropriate" and 52 (25%) "rarely appropriate" and 43 (20%) having "uncertain appropriateness." LIMITATIONS: The methodology requires a focus on appropriateness without comparison between tests and irrespective of cost. CONCLUSIONS: The ultimate decision to order specific tests rests with the physician and is one where the expected benefit exceeds the negative consequences. This publication outlines the recommendations of appropriateness-the AUC for 12 tests used in dermatopathology. Importantly, these recommendations may change considering new evidence. Results deemed "uncertain appropriateness" and where consensus was not reached may benefit from further research.

Evidence behind the use of molecular tests in melanocytic lesions and practice patterns of these tests by dermatopathologists.

BACKGROUND: The gold standard for the diagnosis of melanocytic lesions is histologic examination. However, as histologic examination can have its limitations, there are many clinical scenarios in which additional testing may be appropriate in an attempt to render a definitive diagnosis. METHODS: A literature review for three ancillary tests-comparative genomic hybridization (CGH)/single-nucleotide polymorphism (SNP) array, fluorescence in situ hybridization (FISH), and gene expression profiling by quantitative reverse transcription polymerase chain reaction (qRT-PCR)-was compiled and current use patterns were tabulated. Survey of the practice patterns of these tests by dermatopathologists was also accessed in the attendees of the American Society of Dermatopathology Annual Meeting (Chicago, 2016). RESULTS: Here we summarize the use of these molecular tests in melanocytic lesions. We found that 54.4% of the respondents surveyed utilize (or expect consultants to utilize) molecular testing of melanocytic lesions in their practice when appropriate. CONCLUSIONS: CGH/SNP arrays, FISH testing, and qRT-PCR applied to melanocytic lesions have allowed for more accurate classification. Just over half of those surveyed use molecular testing for melanocytic lesion with the majority sending their cases out for completion of the molecular test.

Appropriate use criteria in dermatopathology: Initial recommendations from the American Society of Dermatopathology.

BACKGROUND: Appropriate use criteria (AUC) provide physicians guidance in test selection, and can affect health care delivery, reimbursement policy and physician decision-making. OBJECTIVES: The American Society of Dermatopathology, with input from the American Academy of Dermatology and the College of American Pathologists, sought to develop AUC in dermatopathology. METHODS: The RAND/UCLA appropriateness methodology, which combines evidence-based medicine, clinical experience and expert judgment, was used to develop AUC in dermatopathology. RESULTS: With the number of ratings predetermined at 3, AUC were developed for 211 clinical scenarios involving 12 ancillary studies. Consensus was reached for 188 (89%) clinical scenarios, with 93 (44%) considered "usually appropriate," 52 (25%) "rarely appropriate" and 43 (20%) "uncertain appropriateness." LIMITATIONS: The methodology requires a focus on appropriateness without comparison between tests and irrespective of cost. CONCLUSIONS: The ultimate decision of when to order specific test rests with the physician and is one where the expected benefit exceeds the negative consequences. This publication outlines the recommendations of appropriateness-AUC for 12 tests used in dermatopathology. Importantly, these recommendations may change considering new evidence. Results deemed "uncertain appropriateness" and where consensus was not reached may benefit from further research.

Clinicopathologic evaluation of cardiofaciocutaneous syndrome: overcoming the challenges of diagnosing a rare genodermatosis.

We report the case of a 2-year-old boy from a family with limited financial resources who presented with cutaneous abnormalities, a history of congenital heart defect, and a presumptive diagnosis of Noonan syndrome. Genetic testing had been deferred because of a lack of funds. Skin findings were characteristic of cardiofaciocutaneous syndrome, including keratosis pilaris, ichthyosis, sparse eyebrows, and multiple nevi. A biopsy of a perifollicular thick papule with background hyperpigmentation was obtained to further characterize the cutaneous findings. Clinical evaluation allowed rapid, cost-effective, specific diagnosis in this patient with a RASopathy-spectrum genetic disorder who did not have access to genetic testing. This time-honored clinical approach is adequate for providing information important for prognosis, follow-up, and counseling. We will also discuss available resources for genetic testing and specialized care for patients with RASopathies.

Diagnostic Methods and Management Strategies of Herpes Simplex and Herpes Zoster Infections.

Herpesviruses are medium-sized double-stranded DNA viruses. Of more than 80 herpesviruses identified, only 9 human herpesviruses have been found to cause infection in humans. These include herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), human cyto-megalovirus (HCMV), Epstein-Barr virus (EBV), and human herpesvirus (HHV-6A, HHV-6B, HHV-7, HHV-8). HSV-1, HSV-2, and VZV can be problematic given their characteristic neurotropism which is the ability to invade via fusion of its plasma membrane and reside within neural tissue. HSV and VZV primarily infect mucocutaneous surfaces and remain latent in the dorsal root ganglia for a host's entire life. Reactivation causes either asymptomatic shedding of virus or clinical manifestation of vesicular lesions. The clinical presentation is influenced by the portal of entry, the immune status of the host, and whether the infection is primary or recurrent. Affecting 60% to 95% of adults, herpesvirus-associated infections include gingivostomatitis, orofacial and genital herpes,and primary varicella and herpes zoster. Symptomatology, treatment, and potential complications vary based on primary and recurrent infections as well as the patient's immune status.

Prominent follicular mucinosis with diffuse scalp alopecia resembling alopecia areata.

A 56-year-old Caucasian female presented with a 2-month history of alopecia. On examination, she had diffuse hair loss of her scalp with some discrete patches of nonscarring alopecia. Histopathology revealed an inflammatory nonscarring alopecia with prominent follicular mucinosis and findings suggestive of alopecia areata. The patient's alopecia completely resolved with oral prednisone. The histopathologic findings and clinical presentation are most consistent with a diagnosis of alopecia areata with follicular mucinosis, although the differential diagnosis is broad. As follicular mucinosis may be associated with both benign and malignant conditions, it is important to be cautious regarding the clinical diagnosis when this reaction pattern is observed histopathologically.

A Case of Pleomorphic Dermal Sarcoma: Giant Exophytic Tumor of the Medial Canthus.

We present the case of a 99-year-old Caucasian female who was referred for treatment of a painless, 8.0 cm × 7.8 cm exophytic, pedunculated, ulcerated tumor of the left medial canthus. Pathology showed spindled, oval, and polygonal cells with pleomorphic nuclei. Many multinuclear giant cells and mitotic figures were also noted. The tumor was highlighted with CD10, showed focal positivity with actin, desmin, and CD68, and had increased Ki67 immunohistochemical staining. The tumor was negative for pancytokeratin, CK5/6, p63, MART-1/MelanA, S100, Sox10, p40, CD34, and CD23. Based on clinicopathologic correlation, the diagnosis of pleomorphic dermal sarcoma (PDS) was made. Pleomorphic dermal sarcoma (PDS) refers to a deep, histologically high-grade tumor that often resembles other tumors clinically and histologically. As PDS is frequently aggressive and related to adverse outcomes, it is important to recognize its distinguishing features in comparison to other similar entities, including atypical fibroxanthoma (AFX) and pleomorphic leiomyosarcoma (PLMS). To our knowledge, there is only one other reported case in the literature of PDS occurring on the eye. By reviewing and understanding characteristic etiologies, locations of presentation, histopathological features, and management techniques, pathologists can make a more accurate diagnosis and dermatologists can provide more effective patient care in a timely manner.

Delayed Onset of Bullous Pemphigoid Secondary to Nivolumab.

The increasing use of immune checkpoint inhibitors, such as nivolumab, a programmed cell death protein 1 (PD-1) inhibitor, for advanced neoplastic disease has revealed significant cutaneous immune-related adverse effects. Herein, we report a case of bullous pemphigoid (BP) secondary to nivolumab therapy for recurrent metastatic oropharyngeal squamous cell carcinoma. In this patient, the time to development of BP was three years, which represents the most delayed onset of BP secondary to a PD-1 inhibitor that has been reported in the literature. Symptoms were initially controlled on low-dose oral prednisone but recurred after two years. The patient was subsequently treated with a several-month taper of high-dose oral prednisone, during which he was able to resume nivolumab without recurrence of skin lesions. Although immune checkpoint inhibitor-induced BP remains rare, physicians should be aware of this serious cutaneous immune-related adverse event as the use of this drug class continues to expand.

Identification of Helicobacter pylori in skin biopsy of prurigo pigmentosa.

A 23-year-old Chinese man presented with a 3-year history of a pruritic eruption. On examination, pink urticarial papules associated with hyperpigmented reticulated patches were noted on his neck, back, and upper chest. Histopathology revealed vacuolar interface dermatitis and numerous gram-negative rods within a dilated hair follicle. The organisms were reactive with anti-Helicobacter pylori immunohistochemisty. The histologic findings and clinical presentation support the diagnosis of prurigo pigmentosa. Additional testing demonstrated a positive urease breath test and serum H. pylori IgG antibodies. The patient was referred to gastroenterology and treated with appropriate antibiotics. After treatment, esophagogastroduodenoscopy revealed chronic gastritis without evidence of H. pylori infection and his skin showed reticulated hyperpigmented patches without evidence of active inflammatory papules. Although previous reports have associated prurigo pigmentosa to H. Pylori gastritis, this is the first report of H. pylori organisms identified in a skin biopsy of prurigo pigmentosa.

A case of topical imiquimod induced fatigue.

Topical imiquimod is used for a variety of common dermatologic lesions, including melanoma in-situ. As an immunomodulator, it is relatively well tolerated with minimal side effects, including scaling, erythema, and edema. Here we present a rare systemic adverse effect, where our patient experienced debilitating severe fatigue when applying imiquimod to a single lesion. Clinicians should be mindful of this side effect and counsel patients appropriately.

scRNA-Seq Reveals New Enteric Nervous System Roles for GDNF, NRTN, and TBX3.

BACKGROUND AND AIMS: Bowel function requires coordinated activity of diverse enteric neuron subtypes. Our aim was to define gene expression in these neuron subtypes to facilitate development of novel therapeutic approaches to treat devastating enteric neuropathies, and to learn more about enteric nervous system function. METHODS: To identify subtype-specific genes, we performed single-nucleus RNA-seq on adult mouse and human colon myenteric plexus, and single-cell RNA-seq on E17.5 mouse ENS cells from whole bowel. We used immunohistochemistry, select mutant mice, and calcium imaging to validate and extend results. RESULTS: RNA-seq on 635 adult mouse colon myenteric neurons and 707 E17.5 neurons from whole bowel defined seven adult neuron subtypes, eight E17.5 neuron subtypes and hundreds of differentially expressed genes. Manually dissected human colon myenteric plexus yielded RNA-seq data from 48 neurons, 3798 glia, 5568 smooth muscle, 377 interstitial cells of Cajal, and 2153 macrophages. Immunohistochemistry demonstrated differential expression for BNC2, PBX3, SATB1, RBFOX1, TBX2, and TBX3 in enteric neuron subtypes. Conditional Tbx3 loss reduced NOS1-expressing myenteric neurons. Differential Gfra1 and Gfra2 expression coupled with calcium imaging revealed that GDNF and neurturin acutely and differentially regulate activity of ∼50% of myenteric neurons with distinct effects on smooth muscle contractions. CONCLUSION: Single cell analyses defined genes differentially expressed in myenteric neuron subtypes and new roles for TBX3, GDNF and NRTN. These data facilitate molecular diagnostic studies and novel therapeutics for bowel motility disorders.

Immunohistochemical differentiation of four benign eccrine tumors.

BACKGROUND: The histogenesis and differentiation of eccrine tumors, including cylindroma, poroma, spiradenoma and syringoma, remains controversial. This controversy may be because of sporadic and incomplete studies of these neoplasms. METHODS: Ten examples each of normal eccrine structures and of four benign eccrine tumors are analyzed with antibodies to cytokeratin (CK) 7, CD34, CK6, CK10, smooth muscle actin (SMA) and CD10. These markers represent two different immunohistochemical stains for each part of the eccrine structure; CK7 and CD34 stain the secretory coil, CK6 and CK10 stain the straight duct and SMA and CD10 stain the myoepithelial cells. This redundancy in staining is performed on four benign eccrine tumors to better interpret the existing literature. RESULTS: We find that CK7 is a sensitive marker for the secretory coil; both cylindromas and spiradenomas express CK7. We also find that CK6 is a marker for the inner ductal cells, while CK10 is a marker for the middle ductal cells; syringomas express both these markers. SMA appears to be a more specific marker for myoepithelial cells surrounding normal eccrine coils, and none of the studied tumors express SMA or CD10. CONCLUSIONS: Our studies suggest that syringomas are tumors of the eccrine duct, while cylindromas and spiradenomas are tumors of the secretory coil.

Posttranslational, translational, and transcriptional responses to nitric oxide stress in Cryptococcus neoformans: implications for virulence.

The ability of the fungal pathogen Cryptococcus neoformans to evade the mammalian innate immune response and cause disease is partially due to its ability to respond to and survive nitrosative stress. In this study, we use proteomic and genomic approaches to elucidate the response of C. neoformans to nitric oxide stress. This nitrosative stress response involves both transcriptional, translational, and posttranslational regulation. Proteomic and genomic analyses reveal changes in expression of stress response genes. In addition, genes involved in cell wall organization, respiration, signal transduction, transport, transcriptional control, and metabolism show altered expression under nitrosative conditions. Posttranslational modifications of transaldolase (Tal1), aconitase (Aco1), and the thiol peroxidase, Tsa1, are regulated during nitrosative stress. One stress-related protein up-regulated in the presence of nitric oxide stress is glutathione reductase (Glr1). To further investigate its functional role during nitrosative stress, a deletion mutant was generated. We show that this glr1Delta mutant is sensitive to nitrosative stress and macrophage killing in addition to being avirulent in mice. These studies define the response to nitrosative stress in this important fungal pathogen.

Function of the thioredoxin proteins in Cryptococcus neoformans during stress or virulence and regulation by putative transcriptional modulators.

The thioredoxin system, consisting of thioredoxin, thioredoxin reductase and NADPH, is known to protect cells against oxidative stress. This disulphide reducing system is present in Cryptococcus neoformans and consists of two small, dithiol thioredoxin proteins and one thioredoxin reductase. In this study, we describe the thioredoxin proteins, Trx1 and Trx2, and present their importance not only to stress resistance, but also to the virulence of C. neoformans. Using real-time polymerase chain reaction, we show the induction of both thioredoxin genes during oxidative and nitrosative stress. We describe through deletion studies that the trx1delta mutant has a severe growth defect and is sensitive to multiple stresses, while the trx2delta mutant is only sensitive to nitric oxide stress. Using gene replacement studies, we demonstrate that the thioredoxin protein products are partially redundant in function, but there is differential gene regulation which is especially important to nitrosative stress resistance. We have also identified two putative transcription factors, Atf1 and Yap4, which appear to differentially regulate the thioredoxin system under different conditions. Atf1 is necessary for oxidative stress induction, and Yap4 is necessary for nitrosative stress induction of the thioredoxin genes in C. neoformans. While these two putative transcription factors each appear to be dispensable for survival in macrophages and virulence in mice, we show the more highly expressed thioredoxin, TRX1, is necessary for survival of C. neoformans in the oxidative environment of macrophages and important for virulence of this fungal pathogen.