A case of diagnostic uncertainty: High-grade melanocytoma versus balloon cell melanoma in a pediatric patient.

An 11-year-old female was referred from an outside institution after a diagnostic biopsy and subsequent excision of a progressively enlarging reddish-brown nodule demonstrated features concerning for a balloon cell nevus with severe atypia versus a high-grade melanocytoma. Upon review of the initial biopsy specimen and molecular data, we favored the diagnosis to be consistent with a high-grade melanocytoma with balloon cell changes while considering the possibility of balloon cell melanoma due to concerning histopathologic and genetic abnormalities. In this case study, we discuss critical diagnostic considerations in this rare pediatric case and highlight important pathologic and clinical features of melanocytomas and balloon cell melanoma.

Myelodysplasia cutis and VEXAS syndrome initially diagnosed as histiocytoid Sweet syndrome: A diagnostic pitfall.

Histiocytoid Sweet syndrome (H-SS) is a histopathological variant of Sweet syndrome (SS) defined by cutaneous infiltration of immature myeloid cells morphologically resembling histiocytes. The association of H-SS with underlying malignancy, particularly myelodysplastic syndromes, is well-established. Myelodysplasia cutis (MDS-cutis) has been proposed to describe cases historically diagnosed as H-SS but characterized by shared clonality of the myeloid infiltrate in skin and bone marrow. Therefore, identifying patients who might have MDS-cutis is critical for the management of the associated hematologic malignancy. VEXAS syndrome, an adult-onset autoinflammatory disease, should also be included in the histopathologic differential diagnosis of H-SS, as it shares clinical and pathologic features with MDS-cutis. Through the presentation of two cases, we aim to highlight the defining features and key clinical implications of MDS-cutis and VEXAS syndrome.

Digital dermatopathology implementation: Experience at a multisite academic institution.

BACKGROUND: Technology has revolutionized not only direct patient care but also diagnostic care processes. This study evaluates the transition from glass-slide microscopy to digital pathology (DP) at a multisite academic institution, using mixed methods to understand user perceptions of digitization and key productivity metrics of practice change. METHODS: Participants included dermatopathologists, pathology reporting specialists, and clinicians. Electronic surveys and individual or group interviews included questions related to technology comfort, trust in DP, and rationale for DP adoption. Case volumes and turnaround times were abstracted from the electronic health record from Qtr 4 2020 to Qtr 1 2023 (inclusive). Data were analyzed descriptively, while interviews were analyzed using methods of content analysis. RESULTS: Thirty-four staff completed surveys and 22 participated in an interview. Case volumes and diagnostic turnaround time did not differ across the institution during or after implementation timelines (p = 0.084; p = 0.133, respectively). 82.5% (28/34) of staff agreed that DP improved the sign-out experience, with accessibility, ergonomics, and annotation features described as key factors. Clinicians reported positive perspectives of DP impact on patient safety and interdisciplinary collaboration. CONCLUSIONS: Our study demonstrates that DP has a high acceptance rate, does not adversely impact productivity, and may improve patient safety and care collaboration.

Artificial intelligence for automatic detection of basal cell carcinoma from frozen tissue tangential biopsies.

Evaluation of basal cell carcinoma (BCC) involves tangential biopsies of a suspicious lesion that is sent for frozen sections and evaluated by a Mohs micrographic surgeon. Advances in artificial intelligence (AI) have made possible the development of sophisticated clinical decision support systems to provide real-time feedback to clinicians which could have a role in optimizing the diagnostic workup of BCC. There were 287 annotated whole-slide images of frozen sections from tangential biopsies, of which 121 contained BCC, that were used to train and test an AI pipeline to recognize BCC. Regions of interest were annotated by a senior dermatology resident, experienced dermatopathologist, and experienced Mohs surgeon, with concordance of annotations noted on final review. Final performance metrics included a sensitivity and specificity of 0.73 and 0.88, respectively. Our results on a relatively small dataset suggest the feasibility of developing an AI system to aid in the workup and management of BCC.

Impact of adding an IgG4 conjugate to routine direct immunofluorescence testing for subepithelial and intraepithelial autoimmune blistering disorders.

BACKGROUND: Certain autoimmune bullous dermatoses are mediated by autoantibodies of the IgG4 subclass. We determined the diagnostic impact of adding IgG4 to our conventional direct immunofluorescence (DIF) panel. METHODS: For all cases submitted to our referral laboratory for DIF over 1 month (n = 630), we performed IgG4 testing and collected consecutive biopsy specimens showing definite or indeterminate linear or cell-surface deposition of IgG, IgG4, and/or C3. On retrospective blinded review, we classified the pattern and whether the findings were definite, indeterminate, or negative. When present, substantial background staining was recorded. RESULTS: Seventy DIF specimens met the inclusion criteria. Of 22 (31.4%) specimens equivocal for linear or cell-surface deposition, 9 (40.9%) had definitive IgG4 findings, either linear (3 of 14 equivocal linear cases; 21.4%) or cell-surface (6 of 8 equivocal cell-surface cases; 75.0%). Background deposition was substantial in 14 cases (20.0%) for IgG but in none for C3 or IgG4. CONCLUSION: IgG4 allowed the classification of over 40% of DIF cases that were otherwise equivocal by IgG and C3. IgG4 staining showed lower levels of non-specific background staining than IgG or C3. IgG4 appears to contribute most value in cases with cell-surface deposition or with equivocal linear IgG deposition and negative C3 results.

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.

Kaposi sarcoma misdiagnosed as granuloma annulare: A case of mistaken identity.

The microscopic features of patch stage Kaposi sarcoma (KS) and interstitial granuloma annulare (GA) may be difficult to differentiate, because both may exhibit a subtle "busy" dermis due to infiltration of spindled cells between collagen bundles. The clinical distinction is particularly challenging in human immunodeficiency virus (HIV)-affected individuals, as the incidence of GA appears to be greater in the HIV-infected population. KS is the most common neoplasm in this population. Despite the significant decrease in the incidence of KS since the advent of highly active antiretroviral therapy (HAART), KS tends to occur with late onset and indolent progression in patients with preserved immune function and minimal viral load. We present a 47-year-old homosexual HIV-positive man, under virologic and immunologic control on long-term HAART therapy, with a 5-year history of progressive red-brown patches and plaques on the legs, feet, hands, and trunk. Prior skin biopsy specimens were interpreted as interstitial GA. Histopathology on new skin biopsy specimens along with review specimens supported the diagnosis of plaque and patch stages of KS, respectively, supported by immunohistochemical expression of human herpes virus-8 (HHV-8). This case underscores the importance of maintaining a high suspicion for KS in progressive, treatment-recalcitrant skin lesions, particularly in HIV-infected individuals.

Kappa and lambda immunohistochemistry and in situ hybridization in the evaluation of atypical cutaneous lymphoid infiltrates.

BACKGROUND: Atypical cutaneous lymphoid infiltrates are challenging lesions in dermatopathology. We present a summary of the literature regarding kappa and lambda immunohistochemistry (IHC) and in situ hybridization (ISH) in the evaluation of atypical cutaneous or mucosal lymphoid infiltrates. METHODS: Relevant articles from 1967 to 2018 in the English language were identified and summarized. In the absence of larger studies, case series of n ≥ 3 were included. RESULTS: Sixty-three articles assessing kappa and lambda IHC and/or ISH were identified. Most focused on marginal zone lymphomas. Other lymphomas included follicle center lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, mantle cell lymphoma, lymphoplasmacytic lymphoma, plasmablastic lymphoma, multiple myeloma, monoclonal gammopathy of undetermined significance, and polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes (POEMS). Non-neoplastic lesions included reactive lymphoid hyperplasia, cutaneous plasmacytosis, connective tissue disease, IgG4-related disease, acrodermatitis chronic atrophicans, Zoon balanitis, dermatitides, and infiltrates around epithelial dysplasias/neoplasias. CONCLUSION: Kappa and lambda IHC and ISH are useful tools in the evaluation of cutaneous B-cell lymphomas and plasma cell neoplasms. The literature supports that the detection of light-chain restriction by IHC and ISH is one of the most useful findings in the differential diagnosis of reactive lymphoid hyperplasia vs B-cell lymphoma with plasmacytic differentiation.

INCREASED INCIDENCE OF CUTANEOUS KERATINOCYTIC AND MELANOCYTIC MALIGNANCIES IN PATIENTS WITH AGE-RELATED MACULAR DEGENERATION.

PURPOSE: The relationship between age-related macular degeneration (AMD) and malignancy, especially cutaneous malignancies, is not well studied. We investigated a possible association between AMD and cutaneous malignancies. METHODS: A retrospective, consecutive review of all patients who had received at least 1 intravitreal injection for wet AMD between January 1, 2004, and December 31, 2013, was conducted using the Rochester Epidemiology Project in Olmsted County, Minnesota. Age- and sex-matched control groups included 473 pre-anti-vascular endothelial growth factor era wet AMD patients, 504 concurrent time dry AMD patients, and 504 patients with no AMD. The rates of AMD and overall malignancy, cutaneous malignancies, and specific types of cutaneous malignancies were compared between groups of patients. RESULTS: Patients with wet AMD incurred an increased rate of overall malignancies compared to patients with dry AMD {52.8% wet AMD (confidence interval [CI]: 48.3-57.2) vs. 43.7% dry AMD (CI: 39.3-48.1); P= 0.003} or those without AMD (52.8% wet AMD [CI: 48.3-57.2] vs. 35.3% no AMD [CI: 31.1-39.7]; P = <0.001). Patients with dry AMD also had higher rates of malignancy than those without AMD (43.7% dry AMD [CI: 39.3-48.1] vs. 35.3% no AMD [CI: 31.1-39.7]; P = 0.007). Rate of cutaneous malignancies was increased in patients with wet AMD compared to patients with dry AMD (24.4% wet AMD [CI: 20.7-28.4] vs. 14.6% dry AMD [CI: 11.5-17.9]; P = <0.001) and those with no AMD (24.4% wet AMD [CI: 20.7-28.4] vs. 9.7% no AMD [CI: 7.3-12.7]; P = <0.001). CONCLUSION AND RELEVANCE: To the best of our knowledge, this is the first report to establish an association between AMD and cutaneous malignancies, supporting a possible discussion of the association when a patient presents with one of the two conditions.

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.

Primary Cutaneous Acral CD8+ T-Cell Lymphoma-A Single Center Review of 3 Cases and Recent Literature Review.

The recently published 2016 revision of the WHO classification of lymphoid neoplasms includes primary cutaneous acral CD8-positive T-cell lymphoma (PCATCL) as a provisional entity. This is a rare indolent lymphoma characterized by papules or nodules on the ear and a dermal infiltrate of CD8-positive T-lymphocytes with cytotoxic marker expression. A retrospective review of a single institutional experience with PCATCL identified 3 patients (mean age 54; range 49-62) with papules or nodules on the ear. Lesional biopsies demonstrated a dense diffuse dermal infiltrate of atypical lymphocytes with a Grenz zone in 2 cases and focal epidermotropism in 1 case. The atypical lymphocytes were predominantly CD3 and CD8 positive with expression of cytotoxic marker TIA1. Staging evaluation failed to reveal systemic disease. Two patients underwent local excision, and the third received local radiation therapy all with complete response and no disease recurrence at last follow-up 3 months (range 2-5 months). Our cases add to the existing limited literature on the clinical and histopathological features of PCATCL. We also performed an updated systematic literature view of the entity.

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.

Cutaneous peripheral T-cell lymphoma, not otherwise specified: A single-center prognostic analysis.

BACKGROUND: Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is a rare and aggressive disease either originating in or secondarily involving the skin. OBJECTIVE: We sought to assess clinical, histopathologic, and prognostic features of patients with cutaneous PTCL-NOS. METHODS: This was a retrospective chart review of patients with cutaneous PTCL-NOS between 1993 and 2013. RESULTS: Thirty patients with PTCL-NOS were included. Fourteen had skin-only disease and 15 had concurrent skin and systemic disease at presentation. In primary cutaneous PTCL-NOS, the overall survival rate at 5 years was 61% (95% confidence interval, 37-100%; number still at risk, 2). The median overall survival was 5.6 years. Patients were diagnosed a median of 2.4 months from symptom onset. Patients with concurrent disease died a median of 2.1 years after diagnosis. The estimated overall survival rate at 5 years after diagnosis was 29% (95% confidence interval, 13-67%; number at risk, 3). The median overall survival was 3.9 years. Patients were diagnosed a median of 6 months from symptom onset, with a 53% increased risk of death for each year from symptom onset to diagnosis. LIMITATIONS: This was a retrospective study with a limited number of cases. CONCLUSIONS: Age at diagnosis and B-symptoms predict poor survival in patients with cutaneous PTCL-NOS. In addition, poorer survival is observed in patients with multifocal lesions and concomitant skin and systemic PTCL-NOS.

Validation of diagnostic accuracy with whole-slide imaging compared with glass slide review in dermatopathology.

BACKGROUND: Teledermatopathology has evolved from static images to whole slide imaging (WSI), which allows for remote viewing and manipulation of tissue sections. Previous studies of WSI in teledermatopathology predated College of American Pathologists (CAP) telepathology validation guidelines. OBJECTIVE: We conducted a comprehensive retrospective WSI validation study of routine dermatopathology cases, adhering to CAP guidelines. METHOD: In all, 181 consecutive cases arranged into 3 categories (inflammatory, melanocytic, nonmelanocytic proliferations) were reviewed by 3 board-certified dermatopathologists via traditional microscopy (TM) and WSI. Intraobserver (TM vs WSI), TM intraobserver and interobserver (TM vs TM), and WSI interobserver (WSI vs WSI) concordance was interpreted using a 3-tier system. RESULTS: TM versus WSI intraobserver concordance (86.9%; 95% confidence interval [CI] 83.7-89.6) did not differ from TM versus TM intraobserver concordance (90.3%; 95% CI 86.7-93.1) or interobserver concordance (WSI: 89.9%; 95% CI 87.0-92.2, and TM: 89.5%; 95% CI 86.5-91.9). Melanocytic proliferations had the lowest TM versus WSI intraobserver concordance (75.6%; 95% CI 68.5-81.5), whereas inflammatory lesions had the highest TM versus WSI intraobserver concordance (96.1%; 95% CI 91.8-98.3). Nonmelanocytic proliferations had an intraobserver concordance of 89.1% (95% CI 83.4-93.0). LIMITATIONS: Efficiency and other logistical WSI parameters were not evaluated. CONCLUSION: Intraobserver and interobserver diagnostic concordance between WSI and TM was equivalent. Therefore, WSI appears to be a reliable diagnostic modality for dermatopathology.

Frozen section diagnosis for non-melanoma skin cancers: correlation with permanent section diagnosis.

Frozen section pathology is routinely used for margin assessment of non-melanoma skin cancer (NMSC). Frozen section can also be used for the primary diagnosis of several skin lesions. Limited data exist on the accuracy of frozen section in the diagnosis of NMSC. We performed a retrospective chart review of 300 cases in which frozen section diagnoses were compared with permanent section diagnoses of NMSC. Frozen section and permanent section pathology were concordant 83.3% of the time, with the highest concordance rates noted for basal cell carcinoma (145/153, 95%). Our results show a high level of concordance between frozen section and corresponding permanent section pathology diagnosis for NMSC. The rapidity of frozen section tissue processing and pathology reporting makes this technique useful in dermatologic practice for immediate diagnosis and management of NMSC. Further studies should explore strategies to decrease or eliminate discrepancies between frozen and permanent section diagnosis.

Dermatopathologists' concerns and challenges with clinical information in the skin biopsy requisition form: a mixed-methods study.

BACKGROUND: Communication failures between clinicians and dermatopathologists are prevalent. Our primary objective was to characterize the concerns and challenges of dermatopathologists posed by incomplete or inaccurate clinical information in the skin biopsy requisition form. METHODS: An explanatory sequential, mixed-methods study design comprised of a survey sent to 1103 members of the American Society of Dermatopathology (ASDP), followed by two focus group sessions. RESULTS: A total of 54% (598/1103) of dermatopathologists completed the questionnaire. Most dermatopathologists (80%; 436/548) viewed their roles to be providers of histopathological diagnosis and a report that is clinically meaningful. Paper or electronic requisition forms were the most common communication method (85%; 458/541) and were associated with the highest rates of dissatisfaction in 36% (193/537) of respondents. Inadequacy of specimens emerged as an important factor influencing judgment of the quality of provided clinical information. 44.7% (261/584) of dermatopathologists spent 30 minutes or more on average every day searching for relevant clinical information to assist with their histopathologic interpretation. CONCLUSION: ASDP dermatopathologists expressed significant dissatisfaction with the quality of clinical information in the requisition form and the time spent gathering information necessary for accurate, timely and clinically meaningful diagnosis. These findings have implications for the quality, safety and efficiency of dermatologic care.

Hypopigmented mycosis fungoides: a clinical mimicker of vitiligo.

Hypopigmented mycosis fungoides (HMF) is a rare variant of cutaneous T-cell lymphoma (CTCL) that often manifests in younger patients with darker skin types in a centripetal distribution.(1) Average age of diagnosis is often 14 years.(2) The diagnosis is often missed due to its low incidence and lack of clinical suspicion. Misdiagnosis and failure to obtain biopsies lead to a long latency period from onset of hypopigmented patches to diagnosis and treatment. HMF has a clinically benign course and responds well to therapy; however, relapse is common.(3) We report a case of HMF misdiagnosed as vitiligo in order to illuminate diagnostic, histopathological, and treatment modalities.