Faculty Bibliography

BRAF inhibitor-induced neutrophilic panniculitis is a rare event that is well-characterized in adults undergoing therapy for metastatic melanoma. To date, there are very few reports of this event in children undergoing BRAF inhibitor therapy for low-grade gliomas, all of which were seen with vemurafenib. We report a case of dabrafenib-induced neutrophilic panniculitis in a 9-year-old girl that manifested within several weeks of initiating dual BRAF-MEK inhibitor therapy for glioblastoma multiforme. This case highlights neutrophilic panniculitis as a side effect of dabrafenib in children and serves as a reminder to consider cutaneous side effects of BRAF inhibitors as they are increasingly used to treat children with primary brain tumors.

Nevus psiloliparus is a rare fatty tissue nevus that is a marker for encephalocraniocutaneous lipomatosis, a neurocutaneous syndrome with ocular and central nervous system anomalies. Clinically, nevus psiloliparus is often described as a congenital alopecia and appears as an irregularly shaped, circumscribed area of alopecia on the scalp. Histopathology demonstrates a near-complete absence of mature hair follicles with preservation of arrector pili muscles and mature adipocytes within the dermis. The pathogenesis of nevus psiloliparus may be related to mosaic mutations in fibroblast growth factor receptor 1. Herein we report the histopathological features of a nevus psiloliparus in an 11-year-old girl diagnosed from transverse sections, which show "shadow" follicular units characterized by columns of loosely arranged collagen and a relative paucity of elastic fibers.

Direct immunofluorescence (DIF) remains a valuable tool that may be underused because of perceived challenges in the interpretation, limitations, and processing of DIF specimens. The aim of this review is to provide a practical guide for appropriately incorporating DIF in a variety of clinical diseases, such as autoimmune blistering disorders. In vasculitis, the role of DIF continues to evolve, particularly in the setting of IgA vasculitis. Although typically not indicated for the workup of connective tissue disease, DIF may be helpful in cases with negative serologies, nondiagnostic histologic findings, or scarring alopecia. Practical pearls for biopsy technique, specimen handling, and storage are also discussed.