Track

Case Reports

Abstract

A 73-year-old woman with rheumatoid arthritis on methotrexate presented with three months of new skin lesions on the left lower extremity. Physical exam was significant for five well-demarcated, red nodules to plaques with a central punched out ulcer on the anterior and posterior leg, involving two dermatomes. Clinically, the lesions were concerning for pyoderma gangrenosum. Microbiological cultures were negative, and a course of prednisone was completed. However, the lesions progressed, and a punch biopsy was performed. Histologic examination revealed dermal and subcutaneous necrosis with microabscesses and lymphohistiocytic inflammation. Notably, there were rare scattered dermal stromal and perivascular cells with enlarged nuclei, smudgy chromatin and foci of viral cytopathic change, which were absent in the epidermis and follicular epithelium. An immunostain for varicella zoster virus (VZV) was positive, supporting the diagnosis of deep VZV infection.  Subsequently, VZV PCR was positive from three of the ulcerated lesions. The patient received valaciclovir with near complete healing of the ulcers after nine weeks. Though herpes viruses (HSV and VZV) typically infect surface epithelial cells leading to vesicle formation, their ability to infect dermal stromal cells has recently been described, coined cutaneous stromal herpes. Cutaneous stromal herpes is a potentially aggressive infection that can clinically mimic pyoderma gangrenosum. Cutaneous stromal herpes occurs in immunocompromised patients and can show atypical and subtle histopathologic manifestations of herpes infection as described herein. Timely, accurate diagnosis of this rare entity is important for appropriate management, and the diagnosis should be considered in immunocompromised patients presenting with pyoderma gangrenosum-like lesions.