Pachydermodactyly (PDD) is a rare and benign acquired form of digital fibromatosis, characterized by asymptomatic fusiform soft tissue hypertrophy of the lateral aspect of the proximal interphalangeal (PIP) joints of the fingers. The etiology of PDD remains unknown, but it usually affects healthy males around the age of puberty. It can be misdiagnosed as inflammatory rheumatic diseases, especially as juvenile chronic arthritis. Here, we report a case of PDD in an 18-year-old man who had progressive fusiform swelling of the PIP joint on his left middle finger. Although he had no pain or functional limitation of movement, he chose to undergo surgical resection of the lesion to obtain a conclusive diagnosis and to rectify the deformity's appearance. Histologically, the lesion was characterized by coarse fibrosis in the adipose tissue, peripheral nerve fibers, and eccrine glands; this is compatible with a diagnosis of PDD.