Dirofilaria tenuis is a mosquito-transmitted filaria of raccoons in the American Southeast. Here, we report the case of subcutaneous D tenuis in a 72-year-old south Florida resident. A 1-cm nodule on the left forearm progressed to an extensive inflammation and radial neuritis with stiffness and weakness of the thumb, index, and middle fingers. His serum was positive for antifilarial IgG1. The determination was based on the history of exposure in Florida and on the characteristics of the degenerating body wall. Removal led promptly to resolution. Subcutaneous D tenuis is usually benign and may simulate lipomas or neoplasms almost anywhere on the body. It should be considered in middle-aged or older patients of either sex who present with a small nodule enveloping a slender coiled roundworm (females, 260–360 μm × 8–13 cm). Florida has accounted for approximately 3 quarters of reported cases.
From the *Division of Infectious Diseases and International Medicine, Department of Internal Medicine, †Infectious Diseases, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida College of Medicine; ‡College of Medicine, University of South Florida; and §Infectious Disease Associates of Tampa Bay, Tampa, FL.
Correspondence to: John Greene, MD, FACP, Infectious Diseases, H. Lee Moffitt Cancer Center and Research Institute, and Medicine and Interdisciplinary Oncology, University of South Florida College of Medicine, 12902 Magnolia Dr, FOB-3, Tampa, FL 33612-9497. E-mail: firstname.lastname@example.org.
The authors have no funding or conflicts of interest to disclose.