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.

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.

Muir-Torre syndrome appropriate use criteria: Effect of patient age on appropriate use scores.

BACKGROUND: Muir-Torre syndrome (MTS) is a rare inherited syndrome, with an increased risk of sebaceous and visceral malignancy. Prior reports suggest screening for mismatch repair (MMR) deficiency may be warranted in patients <50 years and when sebaceous neoplasms are located on a non-head and neck location. Previously, appropriate use criteria (AUC) were developed for clinical scenarios in patients >60 years concerning the use of MMR protein immunohistochemistry (MMRP-IHC). This analysis explores the appropriateness of testing in patients ≤60 years. METHODS: Panel raters from the AUC Task Force rated the use of MMRP-IHC testing for MTS for previously rated scenarios with the only difference being age. RESULTS: Results verify the previously developed AUC for the use of MMRP-IHC in neoplasms associated with MTS in patients >60 years. Results also show that in patients ≤60 years with a single sebaceous tumor on a non-head and neck site, MMRP-IHC testing should be considered. Testing can also be considered with a 2-antibody panel on periocular sebaceous carcinoma in younger patients. CONCLUSIONS: Our findings align with known evidence supporting the need to incorporate clinical parameters in identifying patients at risk for MTS, with age being a factor when considering MMRP-IHC testing.

Multiple perineuriomatous melanocytic nevi.

Perineuriomatous differentiation in solitary cutaneous melanocytic nevi has been described. We present an unusual case of a patient with multiple such perineuriomatous nevi. This presentation raises the possibility that a germline mutation may be responsible for the pathogenesis of these unusual lesions.

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.

Squamous cell carcinoma with enteric adenocarcinomatous differentiation.

We report a highly unusual case of a primary cutaneous squamous cell carcinoma (SCC) with intermixed enteric-type adenocarcinomatous dedifferentiation and a small component of undifferentiated mesenchymal differentiation. We believe this is the first time this form of phenotypic plasticity has been described in cutaneous SCC.

Polymorphous sweat gland carcinoma: a report of two cases.

Polymorphous sweat gland carcinoma (PSGC) is a rare adnexal neoplasm with characteristic variegated histopathologic findings and low-grade clinical behavior. First described in 1994, only 11 cases have been reported in the literature. It is named for the multiplicity of architectural patterns that may be present: solid, tubular, trabecular, pseudopapillary and cylindromatous. Owing to the multiple architectural patterns, the differential diagnosis is broad, including metastatic adenocarcinoma and other adnexal neoplasms with ductular differentiation. We present two new cases of PSGC and review the literature on this rare tumor.

The histone variant macroH2A suppresses melanoma progression through regulation of CDK8.

Cancer is a disease consisting of both genetic and epigenetic changes. Although increasing evidence demonstrates that tumour progression entails chromatin-mediated changes such as DNA methylation, the role of histone variants in cancer initiation and progression currently remains unclear. Histone variants replace conventional histones within the nucleosome and confer unique biological functions to chromatin. Here we report that the histone variant macroH2A (mH2A) suppresses tumour progression of malignant melanoma. Loss of mH2A isoforms, histone variants generally associated with condensed chromatin and fine-tuning of developmental gene expression programs, is positively correlated with increasing malignant phenotype of melanoma cells in culture and human tissue samples. Knockdown of mH2A isoforms in melanoma cells of low malignancy results in significantly increased proliferation and migration in vitro and growth and metastasis in vivo. Restored expression of mH2A isoforms rescues these malignant phenotypes in vitro and in vivo. We demonstrate that the tumour-promoting function of mH2A loss is mediated, at least in part, through direct transcriptional upregulation of CDK8. Suppression of CDK8, a colorectal cancer oncogene, inhibits proliferation of melanoma cells, and knockdown of CDK8 in cells depleted of mH2A suppresses the proliferative advantage induced by mH2A loss. Moreover, a significant inverse correlation between mH2A and CDK8 expression levels exists in melanoma patient samples. Taken together, our results demonstrate that mH2A is a critical component of chromatin that suppresses the development of malignant melanoma, a highly intractable cutaneous neoplasm.

Periocular intralymphatic histiocytosis or localized Melkersson-Rosenthal syndrome?

We describe three cases of periocular edema with histopathologic features of intralymphatic histiocytosis without extravascular granulomas. All were elderly males with no other significant medical problems. Previous reports of periocular Melkersson-Rosenthal syndrome are identical clinically, and some reports show illustrations of intralymphatic histiocytosis histopathologically, in addition to other features typical of the syndrome. Given the lack of associated diseases or other features of the Melkersson-Rosenthal triad, some of these cases may be better defined as periocular intralymphatic histiocytosis.

Proliferating macrophages in human tumours show characteristics of monocytes responding to myelopoietic growth factors.

Macrophages play essential roles in maintaining tissue homeostasis and immune defence. However, their extensive infiltration into tumours has been linked to adverse outcomes in multiple human cancers. Within the tumour microenvironment (TME), tumour-associated macrophages (TAMs) promote tumour growth and metastasis, making them prime targets for cancer immunotherapy. Recent single-cell analysis suggest that proliferating TAMs accumulate in human cancers, yet their origins and differentiation pathways remain uncertain. Here, we show that a subpopulation of CD163+ TAMs proliferates in situ within the TME of melanoma, lung cancer, and breast cancer. Consistent with their potential role in suppressing anti-tumour activities of T cells, CD163+ TAMs express a range of potent immunosuppressive molecules, including PD-L1, PD-L2, IL-10, and TGF-ß. Other phenotypic markers strongly suggested that these cells originate from CD14+ CCR2+ monocytes, a cell population believed to have minimal capacity for proliferation. However, we demonstrate in vitro that certain myelopoietic cytokines commonly available within the TME induce robust proliferation of human monocytes, especially the combination of interleukin 3 (IL-3) and Macrophage Colony-Stimulating Factor 1 (M-CSF). Monocytic cells cultured with these cytokines efficiently modulate T cell proliferation, and their molecular phenotype recapitulates that of CD163+ TAMs. IL-3-driven proliferation of monocytic cells can be completely blocked by IL-4, associated with the induction of CDKN1A, alongside the upregulation of transcription factors linked to dendritic cell function, such as BATF3 and IRF4. Taken together, our work suggests several novel therapeutic routes to reducing immunosuppressive TAMs in human tumours, from blocking chemokine-mediated recruitment of monocytes to blocking their proliferation.

A randomized controlled trial of oral phosphate binders in the treatment of pseudoxanthoma elasticum.

BACKGROUND: Pseudoxanthoma elasticum (PXE) is a rare connective tissue disorder involving fragmentation and mineralization of elastic fibers predominantly in the skin, eyes, and cardiovascular system. OBJECTIVE: The objective of this study was to assess the efficacy of sevelamer hydrochloride on the reversal of elastic fiber calcification and clinical lesions of PXE. METHODS: This was a randomized, double-blind, placebo-controlled, two-part prospective study. In the first year, 40 patients with PXE were randomized to receive either sevelamer hydrochloride (800 mg by mouth three times daily) or placebo in a 1:1 ratio. In the second year, all patients received sevelamer hydrochloride (800 mg by mouth three times daily). RESULTS: In the first year, the placebo and treatment groups' mean calcium scores decreased from 29.52 to 15.97 (41.93% mean improvement) and 27.48 to 16.75 (38.37% mean improvement), respectively. In the second year, the mean calcium scores decreased to 13.36 (53.94%) and 14.03 (51.35%) in these groups. The mean clinical score in the placebo group decreased from 6.25 to 6.05 at year 1 (2% improvement) whereas the mean clinical score in the sevelamer hydrochloride group decreased from 7.10 to 6.55 (7% improvement). In year 2, the scores in the original placebo and sevelamer hydrochloride groups decreased to 5.33 (14% improvement) and 5.72 (19% improvement), respectively. LIMITATIONS: Magnesium stearate in our placebo and active drugs may have played a confounding role in this study, contributing to the small differences observed in these two groups. CONCLUSION: Sevelamer hydrochloride produced a reduction in both calcification levels and clinical scores; however, this difference was not statistically significant compared with placebo. Future clinical studies should examine the inhibitory role and potential therapeutic effect of magnesium in PXE.

Utility of teledermatopathology for intraoperative margin assessment of melanoma in situ, lentigo maligna type: A 6 year community practice experience.

BACKGROUND: Achieving negative margins for melanoma in situ, lentigo maligna type can be challenging, particularly on cosmetically sensitive areas. OBJECTIVE: To assess the utility of intraoperative frozen section margin assessment using a teledermatopathology system in the treatment of head and neck lentigo maligna. METHODS AND MATERIALS: Over a 6 year period, 96 patients with lentigo maligna had surgical excisions. The margins were assessed intraoperatively with frozen sections prepared in the manner used in Mohs surgery. The surgeon guided the frozen section slides around the margin while a dermatopathologist assessed the margin remotely. RESULTS: In 2/96 (2.1%) cases, the safety margin was positive (frozen sections were false negative). In 1 further case (1%) there was a recurrence of the melanoma 13 months following the excision. CONCLUSION: The described method is effective in treating melanoma in situ, lentigo maligna type with clearance rates similar to previous studies for Mohs surgery.

p63 Immunohistochemistry is a useful adjunct in distinguishing sclerosing cutaneous tumors.

Cutaneous sclerosing epithelial neoplasms are often difficult to diagnose. Though various immunohistochemical markers have proved useful, some cases remain a diagnostic challenge. We aimed to assess the utility of p63 immunohistochemical staining in distinguishing microcystic adnexal carcinoma (MAC) from sclerosing basal cell carcinoma (SBCC) and desmoplastic trichoepithelioma (DTE). Biopsy samples from 20 SBCC, 10 DTE, and 5 MAC were examined after immunohistochemical staining with p63. Although all adnexal tumors examined demonstrated p63 expression, the pattern of staining was strikingly different in MAC when compared with other tumor types. MAC exhibited a scattered pattern with p63-positive cells around the periphery of tumor nests and minimal staining within the center of the tumor islands. This pattern was more pronounced at increased depth of infiltration into the dermis. A robust and consistent diffuse pattern of staining with p63 was observed in all SBCCs and DTEs. We believe this pattern reflects the multi-differentiation pathway of MAC, with eccrine/sebaceous differentiation occurring at deeper levels of the dermis. The different staining patterns of MACs compared with DTEs and SBCCs can thus serve asa useful diagnostic adjunct in difficult lesions.

Histopathologic identification of dermal filler agents.

As reflected in the literature, the use of dermal filler agents has increased substantially over the last decade. Consequently, these agents are more frequently encountered on histopathologic examination. A variety of dermal fillers can be readily identified histopathologically, and the accurate identification of these agents is a critical task for dermatopathologists. Furthermore, a basic understanding of the histological features of fillers has relevance to dermatologists and dermatologic surgeons. The identification of filler substances may have important diagnostic, medico-legal and medical management considerations. This concise review aims to provide a pragmatic approach to distinguishing the agents most frequently encountered in routine practice and in the literature.

Osteoinvasive subungual melanoma: a case and review.

Subungual melanoma is a relatively rare variant of melanoma, accounting for 0.7-3.5% of all melanoma cases in the Caucasian population. Curiously, it occurs in 8-33% of cases in black, Asian, Native American and Hispanic populations, which generally face a substantially lower risk of melanoma. Herein the authors report the case of a 69-year-old Hispanic female with a subungual melanoma of the acral lentiginous type that directly invaded the periosteum, cortex and medulla of the distal phalanx. In addition, we review published reports of acral lentiginous melanoma with osseous invasion and discuss the evidence, on a molecular level, for this entity's aggressive pattern of invasion. The review of cases is limited to those found through the PubMed search engine.

Cervical parakeratosis/hyperkeratosis as an important cause for false negative results of Pap smear and human papillomavirus test.

UNLABELLED: Like any screening method, Pap and HPV tests are subject to false negative results. AIM: We investigated the possible relationship between cervical parakeratosis/hyperkeratosis and a false negative result for both Pap and human papillomavirus (HPV) testing. METHODS: A total of 551 cases with diagnostically adequate cervical biopsies and Pap tests performed concurrently were examined. RESULTS: The vast majority of the cases (75.5%) were of concordance in diagnosis. Among the 135 discordant diagnoses were 98 with low-grade squamous intraepithelial lesion (LSIL) biopsy and negative Pap test and 34 with negative biopsy and LSIL Pap test. With rare exceptions, no significant discordance between concurrent biopsy and Pap test was found in the cases of high-grade squamous intraepithelial lesion (HSIL). Cervical parakeratosis/hyperkeratosis was noted in 87.8% of the LSIL biopsies with concurrent negative Pap tests. An 83.3% HPV-negative rate was also observed in this group. By comparison, parakeratosis/hyperkeratosis was less frequent (62.6%) in the SIL biopsies with concordant concurrent SIL Pap tests and usually seen focally when present. The negative HPV rates for these concordant LSIL and HSIL groups were 12.7% and 0.0%, respectively. CONCLUSION: Cervical parakeratosis/hyperkeratosis is an important cause for the negative results of Pap and HPV tests in LSIL, and practising gynaecologist and pathologist should be aware of this possible diagnostic dilemma.

Metastatic Crohn's disease: a histopathologic study of 12 cases.

Perhaps, the most intriguing cutaneous sequela of Crohn's disease (CD) is 'metastatic' CD, defined as sterile granulomatous skin lesions arising at sites discontinuous from the gastrointestinal tract. Though various histopathologic patterns have been described, a lack of a large series has precluded a comprehensive characterization and distinction from the pathologic differential diagnoses. The histopathology features of 12 new cases of metastatic CD were reviewed. Non-suppurative granulomata with a slight cuff of lymphocytes in a nodular or diffuse pattern with an associated superficial and deep perivascular mixed inflammatory infiltrate was the most common pattern. Other common features included an accompanying infiltrate which was often rich in eosinophils, and ulceration of the overlying epidermis. These features are emphasized as potentially useful in distinguishing this entity from its greatest mimicker, cutaneous sarcoidosis.