Ring Finger Mass: A Rare Case of Digital Actinomycosis Surgically Removed From a Young Patient

Abstract

Actinomycosis is an uncommon chronic granulomatous infection that typically resides as commensals in the oral cavity, gastrointestinal tract, and female genital tract. Involvement of the extremities, particularly the digits and underlying bone, is extremely rare, especially in young age, often leading to diagnostic delays and therapeutic uncertainty. A 18-year-old female presented with a progressively enlarging, painless mass on the dorsum of the left ring finger. Clinical examination revealed a firm, non-tender, subcutaneous lesion with no signs of systemic illness. Radiographic imaging demonstrated a lytic lesion with cortical erosion involving the middle phalanx. The mass was surgically excised under local anesthesia without preoperative antibiotic therapy. Histopathological examination confirmed actinomycosis, revealing filamentous bacterial colonies (sulfur granules) within a suppurative and fibrotic background. This case underscores the importance of including actinomycosis in the differential diagnosis of chronic digital swellings, particularly in atypical anatomical sites. Surgical excision remains a valuable diagnostic and therapeutic approach in such rare presentations.