Faculty Bibliography

INTRODUCTION/BACKGROUND:Biopsies of atypical melanocytic nevi are among the most commonly performed procedures by dermatologists. Margin assessment is often used to guide re-excision, but can be a point of confusion as negative margins reported in the planes of sections examined do not always reflect complete removal of a lesion. This study investigates the rates of false negative margins after both punch and shave biopsies. METHODS:We performed a retrospective analysis of 50 consecutive punch and shave biopsy specimens (1) diagnosed as DN, and (2) reported as having clear margins in the planes of section examined. Identified specimen blocks were then sectioned through to examine true margin involvement. RESULTS:Of the 50 specimens identified, 20% (n = 10) were found to have positive margins upon additional sectioning. We found no difference between the groups with respect to biopsy technique, type of nevus, degree of atypia, or gender. CONCLUSION/CONCLUSIONS:This study observed false negative peripheral margin status in a sizeable proportion of biopsy specimens, which did not vary significantly based on biopsy technique or pathologic characteristics. This finding reflects a limitation of standard tissue processing, in which a limited proportion of the true margin is evaluated, and may be of note to many dermatologists who base their decision to re-excise on the reporting of margin involvement. J Drugs Dermatol. 2018;17(7):810-812.

BACKGROUND:Melanocytic immunostains can assist in margin evaluation of melanoma in situ (MIS) excisions; however, their accuracy and reliability relative to hematoxylin & eosin (H&E) is yet to be determined. OBJECTIVE:The objective of this study was to evaluate the sensitivity, specificity, and concordance of 4 melanocyte-specific immunostains for diagnosing MIS occurring on chronically sun-damaged skin. MATERIALS AND METHODS/METHODS:Serial permanent sections from representative areas of negative margin and residual tumor were stained using H&E, MITF, MART-1, SOX10, and R21 and examined in a blinded fashion. The study set included 100 digital microscopy images from 10 cases of MIS excisions from the face. Two board-certified dermatopathologists, 4 fellowship-trained Mohs surgeons, 2 Mohs fellows, and 2 dermatology residents independently reviewed the 100 images. RESULTS:The average melanocyte density was 11 versus 28 melanocytes per 0.5 mm for chronically sun-damaged skin versus residual MIS on H&E, respectively. Statistically significantly higher melanocyte densities were observed using MITF, MART-1, and SOX10 on negative margins. The sensitivity and interobserver concordance was highest using MITF and SOX10. The intraobserver agreement on 4 duplicate images was 85%. CONCLUSION/CONCLUSIONS:In conclusion, the nuclear immunostains (MITF and SOX10) show the most promise for improving the diagnosis of MIS in chronically sun-damaged skin.

This report describes a case of chronic neutrophilic urticarial dermatosis as a presenting feature of systemic juvenile idiopathic arthritis. When encountered in children, neutrophilic urticarial dermatosis should raise suspicion of autoimmune or autoinflammatory disease.

Lichen myxedematosus is condition characterized by localized areas of dermal deposition of mucin, presenting with firm papules localized to few areas of the body. The condition needs to be excluded from scleromyxedema, which, in addition to the firm papular eruption, has areas of induration and is usually associated with a monoclonal gammopathyand systemic symptoms. We present a 62-year-old woman with a several-year history of asymptomatic, firm papules over the face and arms with no evidence of thyroid disease or a monoclonal gammopathy,which is consistent with a diagnosis of localized lichen myxedematosus, the discrete papular variant. The patient is being treated with a topical calcineurininhibitor.

Anetoderma is a rare benign elastolytic disorder that is characterized by focal loss of elastin fibers on histopathology and is often recalcitrant to treatment. We present a case of a patient with a 20-year history of pruritic and painful hyperpigmented atrophic papules clustered on the neck, axillae, inframammary folds, and right medial thigh. Although the histopathologyof her axillary lesions was consistent with anetoderma, her clinical presentation is unusual given the extent of involvement, reported pain and pruritus, and sharp demarcation of the distribution. The diagnosticuncertainty of this case led to added difficulty in management of a disease that is already notoriously difficult to treat and may significantly impact patient's quality of life.

BACKGROUND: Complete removal of individual dysplastic nevi (DN) is often accomplished by a second surgical procedure after the initial biopsy. The choice to perform the second procedure is strongly influenced by histopathologic margin status of the initial biopsy specimen. OBJECTIVE: To evaluate the clinical and histopathologic outcomes of in toto biopsy of DN using a predetermined margin of normal skin. METHODS: We conducted a prospective study of a saucerization method using a defined 2-mm margin in patients undergoing biopsy of a pigmented skin lesion. RESULTS: We performed 151 biopsies in 138 patients. Overall, 137 of 151 lesions subjected to biopsy (90.7%) were melanocytic: 86 DN (57.0%), 40 nevi without atypia (26.5%), and 11 melanomas (7.3%). Of 78 DN, 68 (87.2%) were removed with clear histopathologic margins (8 DN were excluded because of inadequate processing). There was no clinical evidence of recurrence at any of the biopsy sites that were simply observed (i.e., not re-excised) over a median of 16.9 months. LIMITATIONS: There were few biopsies performed on the face. CONCLUSIONS: The complete histopathologic removal of nearly 9 of 10 DN using a peripheral margin of 2 mm of normal skin and a depth at the dermis and subcutaneous fat junction has the potential to decrease second procedures at DN biopsy sites, thereby decreasing patient morbidity and saving health care dollars.

Squamous cell carcinomas (SCCs) are heterogeneous tumors sustained by tumor-propagating cancer cells (TPCs). SCCs frequently resist chemotherapy through still unknown mechanisms. Here, we combine H2B-GFP-based pulse-chasing with cell-surface markers to distinguish quiescent from proliferative TPCs within SCCs. We find that quiescent TPCs resist DNA damage and exhibit increased tumorigenic potential in response to chemotherapy, whereas proliferative TPCs undergo apoptosis. Quiescence is regulated by TGF-beta/SMAD signaling, which directly regulates cell-cycle gene transcription to control a reversible G1 cell-cycle arrest, independent of p21CIP function. Indeed, genetic or pharmacological TGF-beta inhibition increases the susceptibility of TPCs to chemotherapy because it prevents entry into a quiescent state. These findings provide direct evidence that TPCs can reversibly enter a quiescent, chemoresistant state and thereby underscore the need for combinatorial approaches to improve treatment of chemotherapy-resistant SCCs.

For rapid pathological assessment of large surgical tissue excisions with cellular resolution, we present a line scanning, stage scanning confocal microscope (LSSSCM). LSSSCM uses no scanning mirrors. Laser light is focused with a single cylindrical lens to a line of diffraction-limited width directly into the (Z) sample focal plane, which is parallel to and near the flattened specimen surface. Semi-confocal optical sections are derived from the linear array distribution (Y) and a single mechanical drive that moves the sample parallel to the focal plane and perpendicular to the focused line (X). LSSSCM demonstrates cellular resolution in the conditions of high nuclear density within micronodular basal cell carcinoma.