Working Diagnosis:
Felt to be Fibro-adipose Vascular Anomaly (FAVA) vs Venous Malformation (AVM) with differential strongly favoring FAVA

Treatment:
Through shared decision-making across all teams, sclerotherapy, cryoablation, and watchful waiting were offered. The patient was also referred to gynecology to discuss her combined oral contraceptive and its possible role in angiogenesis. Subsequently, she was transitioned to progesterone only contraception.

Outcome:
The pain resolved after a few weeks of medication change, and the lesion was visibly smaller on follow-up ultrasound. The patient opted against sclerotherapy and cryoablation, preferring watchful waiting. She returned to full play once pain began to improve. At 9-month follow-up, she had full range of motion without pain.

Author's Comments:
FAVA is a rare vascular malformation that infiltrates muscle with fibrous-fatty tissue and vascular anomalies. The disease generally affects young adolescent females and presents with pain and restrictions in range of motion. Diagnosis is often made through ultrasound and MRI to look at vascular flow to exclude arterial malformations which cannot be missed. Cryoablation and sclerotherapy are considered first-line options, with surgical resection as second line. There is suspicion that estrogen with its effect on angiogenesis may play a role in the development and waxing-waning nature of FAVA, however, this has not been fully elucidated in the literature. This case is interesting as once the patient started the combined oral contraceptive her symptoms were the most profound she had yet experienced, however, after switching to a progestin only contraceptive, her symptoms fully resolved.

Editor's Comments:
This case illustrates an important and underrecognized diagnostic and management pearl: fibro-adipose vascular anomaly (FAVA) should be considered in the young athlete with atraumatic, episodic, activity-limiting extremity pain and range-of-motion loss, and its clinical course may be hormonally sensitive.

References:
Sanon O, Henderson A, Rosen RJ. Pearls and Pitfalls in the Management of Vascular Anomalies. Semin Intervent Radiol. 2024 Nov 7;41(4):363-369. doi: 10.1055/s-0044-1791279. PMID: 39524232; PMCID: PMC11543104.
Sun YR, Zou ML, Yuan SM. Progress about the fibro-adipose vascular anomaly: A review. Medicine (Baltimore). 2024 Feb 16;103(7):e37225. doi: 10.1097/MD.0000000000037225. PMID: 38363925; PMCID: PMC10869078.
Kulungowski AM, Hassanein AH, Nosé V, Fishman SJ, Mulliken JB, Upton J, Zurakowski D, DiVasta AD, Greene AK. Expression of androgen, estrogen, progesterone, and growth hormone receptors in vascular malformations. Plast Reconstr Surg. 2012 Jun;129(6):919e-924e. doi: 10.1097/PRS.0b013e31824ec3fb. PMID: 22634690.
Utami AM, Halfwerk JBG, de Boer OJ, Mackaaij C, Pabittei DR, van der Horst CMAM, Meijer-Jorna LB, van der Wal AC. Relative expression of hormone receptors by endothelial and smooth muscle cells in proliferative and non-proliferative areas of congenital arteriovenous malformations. Eur J Med Res. 2023 Oct 20;28(1):449. doi: 10.1186/s40001-023-01436-5. PMID: 37864259; PMCID: PMC10588228.

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