An unusual presentation of cutaneous metastatic lobular breast carcinoma.

Breast cancer is the most common malignancy to metastasize to the skin in women. Cutaneous breast carcinoma may arise as cutaneous metastasis or secondary to direct tumor extension to the skin. This report describes an unusual presentation of cutaneous metastatic lobular breast carcinoma that involved diffuse cutaneous lesions and rapid progression from onset of breast mass to development of clinically apparent metastatic skin lesions.

Diagnostic Accuracy of Virtual Pathology vs Traditional Microscopy in a Large Dermatopathology Study.

Importance: Digital pathology represents a transformative technology that impacts dermatologists and dermatopathologists from residency to academic and private practice. Two concerns are accuracy of interpretation from whole-slide images (WSI) and effect on workflow. Studies of considerably large series involving single-organ systems are lacking. Objective: To evaluate whether diagnosis from WSI on a digital microscope is inferior to diagnosis of glass slides from traditional microscopy (TM) in a large cohort of dermatopathology cases with attention on image resolution, specifically eosinophils in inflammatory cases and mitotic figures in melanomas, and to measure the workflow efficiency of WSI compared with TM. Design, Setting, and Participants: Three dermatopathologists established interobserver ground truth consensus (GTC) diagnosis for 499 previously diagnosed cases proportionally representing the spectrum of diagnoses seen in the laboratory. Cases were distributed to 3 different dermatopathologists who diagnosed by WSI and TM with a minimum 30-day washout between methodologies. Intraobserver WSI/TM diagnoses were compared, followed by interobserver comparison with GTC. Concordance, major discrepancies, and minor discrepancies were calculated and analyzed by paired noninferiority testing. We also measured pathologists' read rates to evaluate workflow efficiency between WSI and TM. This retrospective study was caried out in an independent, national, university-affiliated dermatopathology laboratory. Main Outcomes and Measures: Intraobserver concordance of diagnoses between WSI and TM methods and interobserver variance from GTC, following College of American Pathology guidelines. Results: Mean intraobserver concordance between WSI and TM was 94%. Mean interobserver concordance was 94% for WSI and GTC and 94% for TM and GTC. Mean interobserver concordance between WSI, TM, and GTC was 91%. Diagnoses from WSI were noninferior to those from TM. Whole-slide image read rates were commensurate with WSI experience, achieving parity with TM by the most experienced user. Conclusions and Relevance: Diagnosis from WSI was found equivalent to diagnosis from glass slides using TM in this statistically powerful study of 499 dermatopathology cases. This study supports the viability of WSI for primary diagnosis in the clinical setting.

Palisaded neutrophilic and granulomatous dermatitis presenting in a patient with rheumatoid arthritis on adalimumab.

Rheumatoid arthritis (RA) is a chronic inflammatory arthritis that can present with many unique cutaneous manifestations including palisaded neutrophilic and granulomatous dermatitis (PNGD). The authors present a case of PNGD in a RA patient on adalimumab therapy. The potential association of PNGD and adalimumab therapy is discussed as well as a review of the literature of granulomatous eruptions involving patients with RA who are receiving tumor necrosis factor-alpha inhibitor therapy.