Initial immunostain panels for select morphologic scenarios and the differential diagnoses for which they provide support
solitary masses in most cases, but there can be multiple hemangiomas in rare conditions such as Von Hippel-Lindau syndrome or systemic hemangiomatosis syndromes.8,9
borders with a vascular proliferation composed of small aggregates of dilated vessels with smaller sizes compared with the main tumor. This finding has been named “hemangiomatosis.”10 However, this feature is not unique to large hemangiomas and can also be focally seen at the edges of small cavernous hemangiomas.
Figure 26.1 Cavernous hemangioma. The macroscopic appearance of a cavernous hemangioma. The mass displays a red-brown spongy appearance with tan branching septa corresponding to areas of sclerosis.
Figure 26.2 Cavernous hemangioma. This is a cavernous hemangioma composed of variably sized vascular spaces lined by attenuated endothelial cells.
Figure 26.4 Anastomosing hemangioma. The tumor shows an interanastomosing proliferation of capillary-sized vessels. The neoplastic endothelial cells are characteristically devoid of hyperchromasia and significant nuclear atypia.
Figure 26.5 Atypical hemangioma. This lesion had some atypical features, with infiltration into hepatic sinusoids and a slightly increased Ki-67 proliferative rate.
“epidemic” form occurs in patients with AIDS; and (4) the “iatrogenic” form is caused by immunosuppressive drugs administered after organ transplant and has aggressive behavior with a tendency to spread.
Figure 26.7 Epithelioid hemangioendothelioma. An ill-defined tan nodule of epithelioid hemangioendothelioma. Multiple nodules such as this are seen grossly in most cases.
a “burnt out,” fibrotic appearance (Fig. 26.9). At the peripheral of the lesion, the tumor cells tend to grow along hepatic sinusoids. Although the underlying hepatic acinar architecture is preserved, the liver cell plates become gradually atrophic, and eventually disappear and are replaced by tumor. Careful inspection shows scattered tumor cells with intracytoplasmic “blisters” or “vacuoles,” containing red blood cells sometimes, representing primitive vascular lumen formation. In some cases, the neoplastic cells may be obscured by the accompanying inflammatory infiltrate.29
Figure 26.9 Epithelioid hemangioendothelioma. In the liver, tumors frequently show a “burnt out” center which is characterized by hyalinization of the stroma. Intracytoplasmic blister cells can be seen.
vasoformative growth are valuable clues to the correct diagnosis. Mitotic figures, including atypical mitotic forms, are usually easily identified in hepatic angiosarcoma, but may on occasion be difficult to identify. Mitotic activity is not required for the diagnosis of angiosarcoma, particularly when infiltrative growth is present.4
Figure 26.13 Angiosarcoma. The neoplastic cells appear to line collagenous cores creating a papillary appearance.