Soft Tissue, Fibrous hamartoma of infancy

Fibrous hamartoma of infancy is a benign superficial soft tissue tumour that usually presents in the first 2 years of life with 20% presenting at birth. There is a male predominance. Most common sites of involvement include the axillary and inguinal regions, upper arms, trunk and external genitalia. Grossly, these lesions are poorly demarcated. Microscopically, they exhibit a characteristic organoid pattern with 3 components: 1) bands of mature fibrous tissue; 2) nests of immature myxoid or basophilic mesenchyme with primitive ovoid, spindle or stellate cells; and 3) interspersed mature adipose tissue. Treatment is with surgical excision. There is a 15% recurrence rate (probably due to incomplete resection) which can be cured by re-excision.