Swanson, David C.

AbstractBackgroundThe benign and malignant patterns of acral melanocytic naevi (AMN) and acral melanomas (AM) have been defined in a series of retrospective studies. A three‐step algorithm was developed to determine when to biopsy acral melanocytic lesions. This algorithm has only been applied to a Japanese population.ObjectivesOur study aimed to review the current management strategy of acral melanocytic lesions and to investigate the utility of the three‐step algorithm in a predominately Caucasian cohort.MethodsA retrospective search of the pathology and image databases at Mayo Clinic was performed between the years 2006 and 2016. Only cases located on a volar surface with dermoscopic images were included. Two dermatologists reviewed all dermoscopic images and assigned a global dermoscopic pattern. Clinical and follow‐up data were gathered by chart review. All lesions with known diameter and pathological diagnosis were used for the three‐step algorithm.ResultsRegular fibrillar and ridge patterns were more likely to be biopsied (P = 0.01). The majority of AMN (58.1%) and AM (60%) biopsied were due to physician‐deemed concerning dermoscopic patterns. 39.2% of these cases were parallel furrow, lattice‐like or regular fibrillar. When patients were asked to follow‐up within a 3‐ to 6‐month period, only 16.7% of the patients returned within that interval. The three‐step algorithm would have correctly identified four of five AM for biopsy, missing a 6 mm, multicomponent, invasive melanoma.ConclusionWe found one major educational gap in the recognition of low‐risk lesions with high rates of biopsy of the fibrillary pattern. Recognizing low‐risk dermoscopic patterns could reduce the rate of biopsy of AMN by 23.3%. We identified two major practice gaps, poor patient compliance with follow‐up and the potential insensitivity of the three‐step algorithm to small multicomponent acral melanocytic lesions.

AbstractTrichothiodystrophy is a rare autosomal recessive disorder resulting in a broad range of systemic abnormalities. Polarizing microscopy of the hair reveals the pathognomic “tiger tail” of alternating light and dark bands, but the need for a microscope prevents rapid bedside diagnosis. We describe a new technique for the bedside diagnosis of trichothiodystrophy using a handheld polarizing dermatoscope, precluding the need for microscopic examination.

AbstractBackgroundDiagnosis of suspected basal cell carcinoma (BCC) is typically confirmed with incisional biopsy before referral to final surgery.ObjectiveTo investigate the clinical confidence and accuracy of physicians making a diagnosis of BCC based on dermoscopic and reflectance confocal microscopy (RCM) features.MethodsThis study was designed as a simulation to determine the certainty and willingness to refer to surgery without previous biopsy confirmation of BCC. Study subjects were identified with suspected BCC. Dermoscopic and RCM lesion images were obtained before biopsy. Eight clinicians with various expertise levels blindly interpreted these images and chose among four hypothetical treatment options: definite BCC, refer directly to surgery without biopsy; other malignancy, perform biopsy for diagnosis; uncertain diagnosis, perform biopsy; benign, do not biopsy. Decisions for treatment were based on dermoscopic images alone and, subsequently, on dermoscopic and RCM images combined.ResultsThe sensitivity for referral to surgery without biopsy was 67.6% with the use of dermoscopy; the positive predictive value (PPV) was 97.0%. Adding RCM increased the sensitivity to 76.5% and the PPV to 98.6%.ConclusionsDermoscopy provides a high PPV for BCC. The addition of RCM to dermoscopy increases diagnostic sensitivity, particularly in less experienced dermoscopists. Physician behavior might be different if actual referrals were made for surgery without biopsy.