Imaging features of recently identified low-grade vascular neoplasia of the liver: hepatic small vessel neoplasm and anastomosing hemangioma

Category	Detail
Condition	Low-grade vascular neoplasia of the liver (LGVNL), including hepatic small vessel neoplasm (HSVN) and anastomosing hemangioma (AH)
Key Mechanisms	Mesenchymal endothelial cell tumors characterized by small, closely packed vascular channels with minimal cytological atypia and low proliferative activity; mutations in GNAQ and GNA14 genes
Target Population	Adults with hepatic vascular lesions identified on imaging or histology
Care Setting	Tertiary academic hepatobiliary centers with access to advanced imaging and pathology

LGVNL are rare, recently recognized low-grade vascular tumors of the liver with distinct histopathological features and low proliferative index (Ki67 2-5%).
Imaging features include thick peripheral lobulated arterial phase enhancement or a 'flower petal shape' on dynamic CT and MRI, often misdiagnosed as cavernous hemangiomas or malignant lesions.
Due to infiltrative growth pattern in HSVN and uncertain prognosis, surgical resection or long-term follow-up is recommended; no confirmed cases of metastasis or recurrence reported.

Histological confirmation with biopsy or surgical specimen showing small anastomosing vessels, minimal atypia, and positive endothelial markers (ERG, CD31, CD34).
Use of dynamic multiphase contrast-enhanced CT and MRI to identify characteristic imaging features.
Consider differential diagnosis including cavernous hemangioma, hepatocellular lesions, and metastases.

Surgical resection is advised due to infiltrative nature of HSVN and unknown long-term outcomes.
If resection is not performed, long-term imaging follow-up is recommended.

Regular imaging surveillance post-diagnosis or post-resection to detect potential progression or recurrence.
Use of multiphase CT or MRI including arterial, portal, delayed, and hepatobiliary phases when available.

Potential misdiagnosis leading to inappropriate management.
Unknown long-term prognosis; no documented metastases or recurrences except one unconfirmed multifocal HSVN case.
Infiltrative growth pattern in HSVN may complicate complete resection.

Adults diagnosed with LGVNL (HSVN or AH) confirmed by histopathology and imaging

Surgical resection preferred when feasible; otherwise, close imaging follow-up due to uncertain prognosis and infiltrative tumor behavior

Obtain histopathological confirmation with endothelial marker immunostaining for accurate diagnosis.
Perform detailed multiphase contrast-enhanced imaging (CT and MRI) to characterize lesion vascularity and morphology.
Maintain high suspicion for LGVNL in lesions with thick peripheral lobulated arterial enhancement to avoid misdiagnosis.
Recommend surgical resection or long-term follow-up given the infiltrative nature and limited outcome data.
Use multidisciplinary approach involving hepatobiliary radiologists, pathologists, and surgeons for optimal management.

Clinical Scorecard: Imaging Characteristics of Newly Recognized Low-Grade Vascular Tumors in the Liver: Hepatic Small Vessel Neoplasm and Anastomosing Hemangioma