Keratoacanthomas are more common than previously reported in tattoos and are easily misinterpreted. The association with red tattoo ink suggests a form of hypersensitivity-associated with adnexal hyperplasia. Tattoo-associated squamous tumors with innocuous nuclei, infundibulocystic structures, adnexal hyperplasia, and signs of regression should be reported as keratoacanthomas rather than as variants of squamous cell carcinoma.

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm. There are 31 reported cases of cutaneous involvement by PMF, most of which have been described as "extramedullary hematopoiesis." We report a new case of cutaneous involvement by PMF and demonstrate mutation of the Janus kinase 2 gene in the cutaneous lesions. Extramedullary myelofibrosis is best considered a metastatic phenomenon. Reporting such cases as extramedullary hematopoiesis may cause confusion with reactive forms of extramedullary hematopoiesis.

Journal of Cutaneous PathologyDiagnostic concordance rates in the subtyping of basal cell carcinoma by different dermatopathologists Background There are numerous subtypes of basal cell carcinoma (BCC). Defining the histopathologic subtype is an essential element in patient management, but there is little known data regarding interobserver precision in subtyping BCC. Methods We studied interobserver variance between six board-certified dermatopathologists who subtyped 100 BCCs in a blinded fashion. We used kappa statistic to calculate the concordance in suggested subtype by different dermatopathologists. Provided diagnoses were then re-categorized into low-risk and high-risk phenotypes, and kappa statistic for concordance on high-risk BCC was determined. Results The overall κ statistic was 0.301, indicating fair agreement among the six observers. Superficial and fibroepithelial BCC had the highest individual kappa statistics. When subtypes were re-classified into a two-tier system of high-risk and low-risk phenotypes, there was substantial interobserver agreement on high-risk BCC with a κ statistic of 0.699. Conclusion These results suggest only fair agreement among dermatopathologists on specific BCC subtypes, but substantial agreement on superficial, fibroepithelial and high-risk BCC growth patterns. A simplified classification system comprised of superficial, fibroepithelial, nodular and infiltrative subtypes would increase interobserver precision and facilitate clinical decision-making.