Challenges for New Adopters in Pre-Surgical Margin Assessment by Handheld Reflectance Confocal Microscope of Basal Cell Carcinoma; A Prospective Single-center Study.

Introduction: In vivo reflectance confocal microscopy (RCM) is a useful tool for assessing pre-surgical skin tumor margins when performed by a skilled, experienced user. The technique, however, poses significant challenges to novice users, particularly when a handheld RCM (HRCM) device is used. Objectives: To evaluate the performance of an HRCM device operated by a novice user to delineate basal cell carcinoma (BCC) margins before Mohs micrographic surgery (MMS). Methods: Prospective study of 17 consecutive patients with a BCC in a high-risk facial area (the H zone) in whom tumor margins were assessed by HRCM and dermoscopy before MMS. Predicted surgical defect areas (cm2) were calculated using standardized photographic digital documentation and compared to final defect areas after staged excision. Results: No significant differences were observed between median HRCM-predicted and observed surgical defect areas (2.95 cm2 [range: 0.83-17.52] versus 2.52 cm2 [range 0.71-14.42]; P = 0.586). Dermoscopy, by contrast, produced significantly underestimated values (median area of 1.34 cm2 [0.41-4.64] versus 2.52 cm2 [range 0.71-14.42]; P < 0.001). Confounders leading to poor agreement between predicted and observed areas were previous treatment (N = 5), a purely infiltrative subtype (N = 1), and abundant sebaceous hyperplasia (N = 1). Conclusions: Even in the hands of a novice user, HRCM is more accurate than dermoscopy for delineating lateral BCCs margins in high-risk areas and performs well at predicting final surgical defects.

Sentinel Lymph Node Biopsy vs. Observation in Thin Melanoma: A Multicenter Propensity Score Matching Study.

The therapeutic value of sentinel lymph node biopsy (SLNB) in thin melanoma remains controversial. The aim of this study is to determine the role of SLNB in the survival of thin melanomas (≤1 mm). A multicenter retrospective observational study was designed. A propensity score matching was performed to compare patients who underwent SLNB vs. observation. A multivariate Cox regression was used. A total of 1438 patients were matched by propensity score. There were no significant differences in melanoma-specific survival (MSS) between the SLNB and observation groups. Predictors of MSS in the multivariate model were age, tumor thickness, ulceration, and interferon treatment. Results were similar for disease-free survival and overall survival. The 5- and 10-year MSS rates for SLN-negative and -positive patients were 98.5% vs. 77.3% (p < 0.001) and 97.3% vs. 68.7% (p < 0.001), respectively. SLNB does not improve MSS in patients with thin melanoma. It also had no impact on DSF or OS. However, a considerable difference in MSS, DFS, and OS between SLN-positive and -negative patients exists, confirming its value as a prognostic procedure and therefore we recommend discussing the option of SLNB with patients.

Vemurafenib-induced histiocytoid neutrophilic panniculitis simulating myeloid leukaemia cutis.

Neutrophilic panniculitis is an infrequent but characteristic adverse event under therapy with BRAF inhibitors (BRAFi). Since the approval of vemurafenib for treatment of metastatic melanoma in 2011, only two cases of neutrophilic panniculitis in malignancies other than melanoma have been published. Histiocytoid infiltrates of immature neutrophils resembling histiocytes or myelocytes have been reported in Sweet's syndrome and rarely in other neutrophilic dermatoses. We describe a novel variant of neutrophilic panniculitis with histiocytoid myeloid cells in an early lesion from a patient treated with vemurafenib in combination with an anti-EGFR (epidermal growth factor receptor) agent for metastatic colon carcinoma, three weeks after initiation of therapy. Recognizing this variant of panniculitis associated to BRAFi can avoid misinterpretation of the atypical subcutaneous infiltrate as myeloid leukaemia cutis.