_Case Presentation X Photo Vignette _Letter Authors declare that the contents of this article are their own original unpublished findings. Title: Metastatic lung cancer mimicking varicella-zoster virus Authors: Katherine Snow1 BA, Rylee Moody1 MD, Michael Kremer2 MD, Sofia Chaudhry2 MD Affiliations: 1Saint Louis University, School of Medicine, St. Louis, Missouri, USA, 2SSM Health Saint Louis University Hospital, Department of Dermatology, St. Louis, Missouri, USA Corresponding Author: Katherine Snow, 1008 South Spring Avenue, St. Louis, MO 63110, Tel: 314-617-2660, Email: katherine.snow@health.slu.edu Abstract: Cutaneous metastases from lung adenocarcinoma are rare and usually signify advanced disease with a poor prognosis. This case describes a 63-year-old woman with stage IV lung adenocarcinoma who presented with a painful, initially unilateral, rash on her breast. The clinical appearance of erythematous plaques with vesiculo-papules suggested disseminated herpes zoster, leading to the initiation of intravenous acyclovir. However, histopathology revealed atypical epithelial cells consistent with cutaneous metastasis from the primary lung carcinoma. Although cutaneous metastases from lung cancer typically present as nodules, zosteriform skin metastases are extremely rare. This case is a unique instance of bilateral zosteriform skin metastases from lung carcinoma, underscoring the importance of considering cutaneous metastasis in patients with atypical skin lesions and underlying malignancy. Early recognition and accurate diagnosis are crucial for patient management and prognosis.

Blastomyces dermatitidis is a dimorphic fungus that can disseminate in the immunocompetent and immunodeficient. Many infected patients display heterogenous cutaneous findings, making it one of dermatology's great clinical mimics. Cases presenting as single lesions are often mistaken for neoplasms or other infections. We report a patient with diabetes mellitus who presented to the emergency department with a two-month history of an ulcerated jawline nodule. Treatment with incision/drainage and doxycycline for presumed bacterial abscess was unsuccessful. Upon re-presentation 10 days later, biopsy and fungal culture of the tumor confirmed infection with B. dermatitidis. Chest computed tomography revealed disease dissemination. Halfway through a 6-month course of itraconazole, cutaneous and pulmonary findings were notably improved. Diabetes is an emerging risk factor for dissemination that likely contributed to the severity in our case. Early biopsy can prevent potentially life-threatening treatment delays, highlighting the need for blastomycosis to be considered in the differential diagnosis of non-healing wounds.