Fibromatosis Colli
Cyril Fisher, MD, DSc, FRCPath
Key Facts
Terminology
Fibrosing lesion of infants involving muscles of head and neck
Etiology/Pathogenesis
Rarely familial
Obstetric trauma has been proposed as causal factor
Breech or forceps delivery
Found in up to 1/3 of cases of congenital torticollis
Clinical Issues
Majority in lower 1/3 of sternomastoid muscle
Grows rapidly at first then stops and persists
Most cases eventually regress
Microscopic Pathology
Variably cellular fibroblastic infiltrate between skeletal muscle bundles
Early stage more cellular, later scarring
Muscle fibers swell, then atrophy
 Hematoxylin & eosin shows diffuse fibrosis separating muscle fibers and imparting a fine checkerboard-like pattern in this biopsy specimen from the sternomastoid muscle. |
 Hematoxylin & eosin shows hypocellular, finely fibrillary collagen forming a focus of confluent fibrosis in this late-stage example of fibromatosis colli. |
TERMINOLOGY
Synonyms
Sternomastoid tumor
Congenital muscular torticollis
Clinical condition with several associated factors
Only up to 1/3 have fibromatosis colli
Definitions
Fibrosing lesion of infants involving muscles of neck
ETIOLOGY/PATHOGENESIS
Developmental Anomaly
Most cases spontaneous; presumed relation to intrauterine trauma
Rarely familial
Environmental Exposure
Obstetric trauma has been proposed as causal factor
Breech or forceps delivery
Associated with muscular torticollis
Synchronous or delayed
Associated with congenital dislocation of hip, anomalies of foot
