In this paper, we describe two siblings with Juvenile Hyaline Fibromatosis (JHF) who were diagnosed at the age of 34 and 29 years respectively. JHF is a very congenital disease, mainly diagnosed in the first few years of life, with less than 40 published cases in literature. All the main clinical features of this syndrome, which may be summarised as multiple subcutaneous tumours, marked gingival hypertrophy, flexion contractures and osteolytic lesions were present in both of these cases. Clinical, radiological and histological differential diagnosis of JHF were made. Recent information about histopathology, treatment and prognosis of JHF was also reviewed.