ISSVA Classification of Vascular Anomalies and Molecular Biology

Abstract

Vascular anomalies include various diseases, which are classified into two types according to the International Society for the Study of Vascular Anomalies (ISSVA) classification: vascular tumors with proliferative changes of endothelial cells, and vascular malformations primarily consisting of structural vascular abnormalities. The most recent ISSVA classifications, published in 2018, detail the causative genes involved in many lesions. Here, we summarize the latest findings on genetic abnormalities, with the presentation of the molecular pathology of vascular anomalies.

Transcriptional data analysis reveals the association between infantile hemangiomas and venous malformations

“…superficial veins, purple vein bubbles, or blue tinge involving the skin (Kunimoto et al, 2022). Medical interventions or surgical treatments are required by 45% of patients with vascular anomalies (Haggstrom et al, 2006).…”

Epithelioid Vascular Lesions: The Differential Diagnosis and Approach in Cytology and Small Biopsies

“…In fact, granulation tissue and reactive changes can have associated vascular proliferations that may give rise to a mass lesion that undergoes biopsy and are quite common lesions that could be confused with a vascular neoplasm. 1,3 Thus, simply recognizing increased vascularity often does not indicate that the mass is vascular in origin. This is also complicated by the fact that many nonvascular tumors show increased vascularity, such as low-grade neuroendocrine tumors, renal cell carcinomas, melanomas, and choriocarcinoma.…”

“…Malignant epithelioid vascular neoplasms can show a range of nuclear pleomorphism from between mild to moderate and ranging up to severe. Vascular lesions may demonstrate confluent lobules or "cannonballs" of spindled endothelial cells with slit-like lumina embedded in a fibrotic background 3 or rounded pleomorphic, malignant endothelial cells appearing polygonal, or fusiform and may have epithelioid appearance. In well-differentiated areas, functioning vascular sinusoids continuous with normal vascular channels may also be evident.…”

“…Although a small subset of angiosarcomas demonstrates epithelioid morphology, EAS has an aggressive clinical course with dismal 5-year survival compared with conventional angiosarcoma. 1,3,16,19 It tends to occur in the deep soft tissue of an extremity, with male predominance, and often metastasizes to lymph nodes, in addition to the lung, bones, soft tissue, and skin. The hematogenous route of metastases to the lung and bone is expected for sarcomas, but the lymphatic spread is relatively unique to a small set of sarcomas, including EAS.…”

“…Vascular neoplasms may also present clinically in a variety of ways and affect a large spectrum of body sites as a primary or metastatic lesion 1. Accessing these lesions for a biopsy to obtain a diagnosis and ancillary studies may present challenges for the proceduralist or radiologist due to the risk of bleeding, in addition to diagnostic challenges on the interpretation side due to the rarity of these lesions 3. The radiologic imaging characteristics can sometimes raise the possibility of a vascular lesion, and these findings, along with the location of the lesion, can help in determining the approach to the biopsy 4.…”