Fibromatosis Colli
Pronunciation: fy-bro-mah-TOH-sis KOL-eye
A benign fibrous proliferation within the sternocleidomastoid muscle of neonates, presenting as a neck mass and typically associated with birth trauma or abnormal intrauterine positioning.
Full Definition
Fibromatosis colli is a non-neoplastic fibrous lesion of the sternocleidomastoid (SCM) muscle that presents in the first weeks of life as a firm, palpable neck mass. Histologically, it shows replacement of normal muscle fibres by fibroblasts and collagenous stroma, without nuclear atypia or significant mitotic activity. The aetiology is thought to involve ischaemia or traumatic disruption of the SCM during delivery. It is the most common cause of a neonatal neck mass and typically resolves with physiotherapy. Editors should distinguish it from infantile fibrosarcoma, fibromatosis (desmoid type), and other soft-tissue tumours when editing paediatric head and neck pathology reports.
Usage
Usage note: 'Sternomastoid tumour of infancy' is a common synonym but may misleadingly imply malignancy; prefer 'fibromatosis colli' in formal pathology documents.
In Context
- "Ultrasound-guided biopsy of the neonatal neck mass showed features consistent with fibromatosis colli rather than a neoplastic process." — Radiology-pathology correlation report
- "The editor replaced the informal term 'sternomastoid tumour' with the preferred designation 'fibromatosis colli'." — Copy-editing log