Clinicopathological Characteristics, Gene Mutations, and Treatment of Fibro-adipose Vascular Anomaly: A Case Series From China and Literature Review.

Purpose: The objective of this study is to offer a thorough overview of the clinical and pathological characteristics, potential pathogenic genes, treatment modalities, and prognoses of a cohort of Chinese individuals diagnosed with Fibro-adipose Vascular Anomaly (FAVA). This study aims to advance the comprehension of this specific medical condition.

Methods: A total of 15 cases of FAVA patients admitted to our center between June 2015 and December 2023 were included in this study. Clinical symptoms, laboratory tests, imaging findings, and pathological data were systematically reviewed to outline the clinical and pathological features of FAVA. Furthermore, whole-exome sequencing was conducted on lesion samples from five patients to identify potential pathogenic genes. The treatment modalities encompassed sclerotherapy and surgical interventions, with treatment outcomes assessed based on clinical symptoms, imaging characteristics, and enhancement of limb functions.

Results: The FAVA lesions were predominantly located in the limbs in 14 patients and in the trunk in 1 patient. The clinical manifestations included pain (9/15, 60%), muscle contracture deformity (3/15, 20%), and joint dysfunction (3/15, 20%). Coagulation function assessments indicated that 3 patients exhibited localized intravascular coagulation (LIC). Magnetic resonance imaging (MRI) findings displayed mixed vascular malformation components and fibrofatty components within the muscles, showing isointense or hyperintense signals on T1-weighted images and heterogeneous hyperintense signals on T2-weighted images. Histopathological analysis revealed activation of the PI3K-AKT-mTOR signaling pathway. Whole-exome gene sequencing of 5 cases identified 10 genes potentially linked to pathogenicity. All patients underwent ethanol sclerotherapy. Surgical intervention was performed on five patients due to muscle contracture and joint dysfunction. Some patients reported pain relief following sclerotherapy, whereas those who underwent surgery demonstrated significant enhancement of joint function.

Conclusions: The Chinese patients diagnosed with FAVA in this study presented characteristic clinical symptoms, imaging features, and pathological traits. The lesion tissue showed activation of the PI3K-AKT-mTOR signaling pathway, with only one patient (1/5, 20%) exhibiting a PIK3CA mutation. This finding underscores the intricate nature of the pathogenic genes and pathogenesis of FAVA. Although sclerotherapy demonstrated restricted efficacy in alleviating pain symptoms, surgical intervention was deemed necessary for addressing joint dysfunction resulting from muscle contracture.