Orthopedic Surgery for Hemangioma Workup

If a patient presents with history, physical examination findings, and imaging study findings consistent with hemangioma, no laboratory studies are necessary.

For patients with intramuscular hemangiomas who manifest petechiae, easy bruising, or ecchymoses, Kasabach-Merritt syndrome should be considered. In this syndrome, a complete blood count (for hemoglobin, hematocrit, and platelets) and coagulation studies (eg, prothrombin time [PT], activated partial thromboplastin time [aPTT], thrombin time [TT], fibrinogen, fibrinogen degradation products [FDPs]) are recommended for evaluation. Hemoglobin and hematocrit can be decreased if hemorrhage is significant. Platelet counts can fall to 20,000/μL or less. PT may be mildly elevated. Serum fibrinogen may be decreased, and FDPs may be elevated.

If tumor-induced osteomalacia is suspected on the basis of radiographic findings, serum calcium, phosphorus, parathyroid hormone (PTH), and alkaline phosphatase (ALP) should be checked. Serum calcium will be in the low-to-normal range, marked hypophosphatemia will be present, PTH will be within the reference range, and ALP will be elevated.

Intramuscular hemangiomas

Radiography

Soft-tissue hemangiomas may be seen on radiographs as soft-tissue shadows, though they are typically isodense with muscle. ^{[28, 29]}  They may cause benign-appearing periosteal reaction or chronic cortical thickening and remodeling in adjacent bone (see the image below).

Phleboliths within the soft-tissue mass are diagnostic but are not common. These small, round, calcified densities occur within organizing thrombi within the vascular structures of hemangiomas (see the image below). They should be carefully evaluated to be differentiated from the mineralization that can occur within certain soft-tissue sarcomas.

Magnetic resonance imaging

After plain radiography, magnetic resonance imaging (MRI) is the imaging modality of choice for soft-tissue hemangiomas, including those of muscle and synovium (see the image below). ^{[28, 29, 30]}

Hemangiomas show increased signal on both T1- and T2-weighted images because they have both fat and fluid content. They frequently have areas of signal void. These void areas may be indicative of dense fibrous tissue, thrombi, phleboliths, or regions of high flow.

The diagnosis of hemangioma may be made with MRI when these signal characteristics are present and when the serpentine pattern of the vascular structures is depicted, usually with interposed fat as well. The margins of hemangiomas range from very infiltrative and irregular to well marginated, but they are often less well-circumscribed than those of soft-tissue sarcomas.

Increased signal with gadolinium enhancement also may be helpful in distinguishing hemangiomas from nonneoplastic soft-tissue masses.

Angiography

Angiography reveals a highly vascular lesion with vessels oriented parallel to one another. ^{[28, 29]}  The lesions may be high-flow or low-flow. This distinction between high-flow and low-flow lesions can be important in treatment decisions, in that the former are more likely to benefit from embolization than the latter. However, angiography cannot reliably differentiate hemangiomas from soft-tissue sarcomas.

Ultrasonography

A study by Tang et al found color Doppler ultrasonography (US) to have a high rate of diagnosis for intramuscular hemangioma. ^[31]  

Synovial hemangiomas

Radiography

Synovial hemangiomas result in nonspecific changes on plain radiographs, occasionally including a vague soft-tissue density. ^[32]  Erosion of bone is rarely present.

Magnetic resonance imaging

MRI is useful in the diagnosis of synovial hemangiomas. The signal characteristics are similar to those of intramuscular hemangiomas (increased signal on T1 and T2, and depiction of vascular structures). In addition, MRI can provide information as to whether a synovial hemangioma is localized and pedunculated or diffuse (see the image below). This information helps in planning treatment. Finally, MRI can be used to diagnose other pathologic processes in the differential diagnosis of a synovial hemangioma (eg, meniscal tear).

Angiography

This study reveals pooling over the mass, consistent with a vascular process.

Osseous hemangiomas

Radiography

Hemangiomas of bone have different radiographic characteristics in different anatomic locations. In the skull, they produce lytic lesions that are well circumscribed and may have a honeycomb appearance. Fine, radiating striations are frequently present, creating a sunburst or sunray appearance. The cortex often is expanded in the skull.

In the vertebral bodies, the parallel vertical trabeculae have a pathognomonic appearance, often referred to as "corduroy cloth," "honeycomb," or "jailhouse" appearance (see the image below). The cortex is not expanded in the vertebrae. ^[33]

In the long bones, radiographic findings typically are less specific, with a coarse or bubbly appearance. Occasionally, the appearance may be primarily or completely lytic with a sclerotic rim.

Computed tomography

Computed tomography (CT) occasionally is used in identification of osseous hemangiomas but generally is not used to evaluate soft-tissue hemangiomas. Vertebral body hemangiomas have a distinctive polka-dot appearance on axial CT (see the image below).

Magnetic resonance imaging

The characteristic MRI appearance is a hyperintense, mottles, or "starburst" signal on T1-weighted and T2-weighted images. Vertebral hemangiomas can be identified by the jailhouse appearance on sagittal sections (see the first image below), similar to that seen on radiographs, and by the polka-dot appearance seen on axial sections (see the second image below).

A study by Cross et al found that characteristic findings associated with vertebral hemangiomas were absent in 35% of plain films, 20% of CT scans, and 48% of MRI scans of aggressive lesions, resulting in an inability to make an accurate diagnosis. ^[34]

Gorham disease

Radiography

Massive osteolysis is evidenced by what appears to be dissolution of a bone or of adjacent bones in which the ends become tapered, as in the image below. The disease is characterized by intramedullary and subcortical radiolucent foci that appear as patchy osteoporosis. The disease slowly progresses in an irregular fashion and may evolve into an extraosseous process. It may present as an intraosseous process demonstrating a scooped-out appearance of the bony tissue.

Intramuscular hemangiomas

The differential diagnosis for the clinical and radiographic findings associated with intramuscular hemangiomas includes soft-tissue sarcoma. Therefore, when the clinical and radiographic findings are equivocal, biopsy is indicated. Biopsy can be performed by means of needle or open techniques. Excessive bleeding should be anticipated in most cases.

Osseous hemangiomas

The most significant entities in the differential diagnosis of hemangioma of bone are osseous angiosarcoma and metastatic disease. ^[35] As with soft-tissue hemangiomas, when the clinical and radiographic findings are equivocal, biopsy is indicated. Biopsy can be performed by means of needle or open techniques. ^[36]

Hemangiomas may have a spectrum of histologic findings. ^[37] In a simplistic classification schema, hemangiomas can be divided into the following three types:

• Capillary (small-vessel)
• Cavernous (large-vessel)
• Mixed

Capillary hemangiomas have abundant vessels approximately 10-100 μm in diameter with walls one to three cells thick. The vessels tend to run in parallel. There is a single layer of endothelial cells with no shedding and no anaplasia. Cavernous hemangiomas have a similar appearance, but the lumina are bigger.

A cellular type also has been described in which a much higher number of cells are present, distinct lumina are still identifiable, and no shedding or anaplasia is seen. There may be smaller areas within a cellular type that resemble capillary hemangiomas.

Using a more refined classification schema, Enzinger and Weiss divided localized hemangiomas into seven categories, as follows ^[38] :

• Capillary hemangioma, including juvenile
• Cavernous hemangioma
• Venous hemangioma
• Arteriovenous hemangioma (racemose hemangioma)
• Epithelioid hemangioma
• Hemangioma of granulation tissue
• Miscellaneous hemangiomas of deep soft tissue (including many of the hemangiomas important to orthopedists, specifically synovial and intramuscular hemangiomas)

Cells within a hemangioma can be stained for factor VIII; positivity indicates that the cells are endothelial. A group in New Zealand defined three suggested phases of hemangioma development (proliferative, involuting, and involuted) by histochemical and immunohistochemical means. Findings included the following:

• Both CD31 and von Willebrand factor (vWF) stained vascular endothelial cells in tumors of each phase
• Proliferating cell nuclear antigen was predominant in the proliferative and involuting hemangiomas, but negligible in the involuting phase
• Mast cells were identified predominately in the involuting phase hemangiomas
• Vascular endothelial growth factor (VEGF) was identified primarily during the proliferative phase
• Basic fibroblast growth factor (bFGF) was identified during the proliferative and early involuting phases

Whereas these studies generally are not necessary for diagnosis, they provide insight into the biology and development of hemangioma.

Electron microscopy can be used to identify Weibel-Palade bodies. These bodies are rod-shaped, ranging from 0.1 to 0.3 μm in length, and contain parallel tubules that localize factor VIII–associated antigen. They are relatively specific to endothelial cells.

Intramuscular hemangiomas

Intramuscular hemangiomas (see the images below) may be capillary, cavernous, or mixed in type. They can be distinguished from skeletal-muscle angiosarcomas because they do not develop the freely anastomosing sinusoidal pattern seen in certain angiosarcomas. In addition, hemangiomas do not have the nuclear pleomorphism and hyperchromatism seen in angiosarcomas. It may be more difficult to distinguish hemangiomas from hemangioendotheliomas, but hemangioendotheliomas may have shedding and cellular atypia. Hemangiomas can be differentiated from angiolipomas by the absence of lipoblasts in hemangiomas.

Synovial hemangiomas

Synovial hemangiomas are of the cavernous type. The matrix between the vessels may be edematous, myxoid, or focally hyalinized. The cells may contain significant amounts of hemosiderin.

Osseous hemangiomas

Most hemangiomas of bone are cavernous, though they may also be a mixture of capillary and cavernous. There may be reactive new-bone formation, which can appear similar to an osteoblastoma. Hemangioendothelioma of bone may be distinguished by a plumper endothelial lining and varying degrees of cellular atypia.

Gorham disease

Histologic findings in Gorham disease can include benign hemangiomatosis, lymphangiomatosis, or sinusoidal channels of vascular or lymphatic origin. ^[11] The vascular component appears as densely packed fibrovascular tissue at sites of bony destruction and as capillarylike lumens at sites of bone preservation.