- Also known as sternocleidomastoid (SCM) tumor of childhood or congenital torticollis (Sabounji et al. 2022, Nasri et al. 2021)
- A benign fibroblastic proliferation of the SCM, most commonly on the right side (Aljahdali et al. 2023)
- Rare lesion with an incidence of 0.4% of live births, mostly affecting male infants (Aljahdali et al. 2023)
- Often associated with breech or forceps deliveries (Aljahdali et al. 2023)
- Heredity and infection may also play a role in the etiology (Aljahdali et al. 2023)
- May present with torticollis in 14-71.4% as reported in various studies (Sabounji et al. 2022)
- On exam, a non-tender mass is found in the region of the sternocleidomastoid in an infant (Aljahdali et al. 2023)
- Ultrasound is the key imaging modality to show muscle enlargement and confirm the diagnosis (Nasri et al. 2021)
- On CT: no calcifications or signs of inflammation (no fat-stranding or edema); non-enhancing with contrast
- On MR:
- T1 shows a fusiform enlagement of the SCM with isointensity to muscle
- Isointense to muscle unless fibrosis present (appears hyperintense) on T2
- T1 post-contrast will show enhancement
References
Sabounji SM, Gueye D, Fall M, Ndour O, Ngom G. Fibromatosis Colli: About 26 Cases. J Indian Assoc Pediatr Surg. 2022 Sep-Oct;27(5):534-536. doi: 10.4103/jiaps.jiaps_174_21. Epub 2022 Sep 9. PMID: 36530812; PMCID: PMC9757773.
Nasri S, Afilal I, Missaoui Z, Aggari HE, Kamaoui I, Aichouni N, Skiker I. Fibromatosis Colli: A case report. Radiol Case Rep. 2021 Dec 28;17(3):693-695. doi: 10.1016/j.radcr.2021.12.009. PMID: 35003462; PMCID: PMC8718815.
Aljahdali NF, Alolah AA, Alghamdi AA, Alharthi FF, Aljaziri NJ. Fibromatosis Colli: A Case Report. Cureus. 2023 Oct 19;15(10):e47308. doi: 10.7759/cureus.47308. PMID: 38022171; PMCID: PMC10657154.