Fibrous Hamartoma of Infancy : Introduction

Comments:
Introduction: Fibrous hamartoma of infancy (FHI) is a rare benign fibrous tumor of childhood with a characteristic organoid, triphasic appearance consisting of intersecting fascicles of cytologically bland fibroblastic/myofibroblastic cells (pink areas in this image), vascular nodules of primitive mesenchymal tissue (left half of the image), and mature adipose tissue.

Clinical Features: More than 90% of cases occur in the 1st year of life (range - birth to 15 years; median age 10 months). About 20% of cases are congenital. It is more common in boys (M:F=3:1).

Sites: The most common location is axilla followed by shoulder, upper arm, back, thigh, genital area, chest and forearm. Hands and feet are rarely affected. It presents as a small, solitary, painless, rapidly growing mass that is freely mobile but may sometimes be fixed to the fascia. After initial rapid phase, the growth slows but the lesion does not regress spontaneously.