Vascular cell tumors are the most common tumors of childhood and account for up to 65 % of the tumors in children (Fleming and Smith 2000). Congenital vascular lesions can be categorized into two groups: hemangiomas (growths that involute) and vascular malformations (noninvoluting tumors). There is a threefold increased incidence of hemangiomas in females (Walsh and Eady 2004). Thirty percent of hemangiomas are present at birth, with almost all visible by 4 weeks of age. Rapid growth is followed by spontaneous involution. Malformation, however, is present at birth but may not manifest until late in life. They affect males and females equally (McClinton 1993). They enlarge proportionally with overall growth unless stimulated by hormonal influences, infection, or surgery (Walsh and Eady 2004).

These are true vascular tumors with a characteristic three-phase growth cycle. They are noted in the first 4 weeks of life. The first phase consists of rapid cell growth and proliferation. This leads to a maximum tumor size by 10–12 months of age (McClinton 1993). This rapid growth, disproportionate with the child’s growth, can lead to fears of a sarcoma. However, at the end of the phase, the mass is firm and does not change in size or consistency with arm elevation. The color appearance can range from normal flesh tone to a deep red or blue.

The second phase in the growth cycle involves slow growth that matches the growth of the child (Upton and Coombs 1995). The color appearance changes from a brighter hue to a less reactive dull red or purple.

The third and final phase is involution and tends to occur somewhat slowly. Approximately 50 % of tumors have regressed by age 5 years and 70 % by age 7 years (Walsh and Eady 2004). Clinical appearance includes softening, shrinking, reduced tenderness, and resolution of color changes. Wrinkled skin, telangiectasias, and a fibrofatty mass may be all that is left after involution.

Increased estrogen levels in children with hemangiomas, the female predominance, and the decrease in estrogen levels during successful treatment all point to a hormonal association. However, research to the origin of these tumors has yet to show a causal agent.

A variety of modalities can be used for imaging. Radiographs rarely show mass effect on adjacent bone or skeletal hypertrophy (Fleming and Smith 2000). Ultrasound tends to depict a mass lesion. Angiograms will show a well-circumscribed mass with a blush, with equatorial feeding vessels and peripheral draining vessels noted (McClinton 1993). Tc-99 m red blood cell perfusions and blood pool scintigraphy show highly increased activity on early and late blood pool images and increased perfusion in the mass (Lim et al. 2002). Magnetic resonance imaging shows a well-circumscribed mass that enhances with gadolinium. The vascular portion produces a heterogeneous, extremely high T2 signal. Infiltrative margins and an overgrowth of fatty tissue produce a high T1 signal (Theumann et al. 2001). A serpentine pattern within the mass may be noted (Memis et al. 1996).

Histologic features on biopsy specimens include an increased number of mast cells, plump endothelium with rapid turnover, and a multilaminated basement membrane (Fleming and Smith 2000).

Primary platelet trapping can occur within the hemangioma and can be associated with gross thrombocytopenia (Kasabach-Merritt syndrome) (Walsh and Eady 2004).

Initial treatment usually consists of observation except if a large tumor is causing systemic hematologic changes as stated above. Splinting and pressure garments can help reduce symptoms caused by tissue stretch. Ulceration and superficial bleeding occurs in 30 % of patients during the proliferative phase (Walsh and Eady 2004). These can be controlled with local measures. If bleeding is uncontrolled and secondary to the syndrome described above, aggressive medical treatment is warranted. This may include transfusions.

Steroids (intralesional or systemic) have a mixed rate of success ranging from 30 % to 90 % (Fleming and Smith 2000). They are used for larger lesions requiring transfusions.

Treatment with laser application using a pulsed dye argon device is most effective in early, macular lesions. It is also useful as a cautery device in ulcerated, bleeding lesions (Fleming and Smith 2000). Skin changes due to treatment include scarring, hypopigmentation, and epidermal atrophy.

The most aggressive medical treatment is using interferon alpha 2a or 2b for severe hemangiomas (Castello et al. 1997). It is used for massive lesions when other forms of medical therapy such as steroids have been exhausted and surgery is not possible. Side effects include neutropenia, elevated liver enzymes, and spastic diparesis. Results are mixed with reports of both dramatic success (Castello et al. 1997) and failure and death (Teillac-Hamel et al. 1993).

Surgery is usually unnecessary, except in cases of proliferative, localized lesions in which bleeding cannot be controlled. Surgical excision is easier in the proliferative phase because of the formation of a pseudocapsule. Excision during the maturation and involution phases may be more difficult because the margins are less defined (Fleming and Smith 2000).

These lesions are present at birth but quiescent. They become apparent later in life, with most appearing between the ages of 2 and 5. Growth is proportional with the child’s normal skeletal growth, and involution does not occur (Upton and Coombs 1995). There is an equal incidence in males and females. They are subdivided into two categories based on the rate of blood flow within the lesion: low flow and high flow. Low-flow lesions are far more common than high-flow lesions with a 7:1 ratio (Fleming and Smith 2000). They tend to be soft and compressible. They are usually biologically inert, in contrast to the active changes seen in hemangiomas (Walsh and Eady 2004).

Histologically, endothelial cells are flat, and mast cell numbers are normal. Basement membranes are flat and not multilaminated.

A low-grade consumptive coagulopathy may be present.

Radiographs may show phleboliths, skeletal hypertrophy, distortion, or frank destruction, depending on the flow characteristics of the malformation. Ultrasound evaluation will show channels, and flow parameters can be measured. Angiography will show vessel anatomy, but no blush will be present (Walsh and Eady 2004). MRI with gadolinium can assess the extent of the malformation and tissue involvement.

Vascular malformations are possibly caused by a defect in signaling between cells during embryonal angiogenesis. This results in distended, tortuous vessels with dilated lumens (Fleming and Smith 2000).

Low-flow malformations are further subdivided into capillary, venous, lymphatic, and combined types, depending on the predominant defective vessel type.

Capillary malformations are caused by dilated capillaries and postcapillary venules in the upper dermis of the skin. Other terms used to describe capillary malformations are port-wine stain and nevus flammeus. They appear dark red or purple and may be associated with another, deeper malformation. Laser can be used to treat these lesions; however, this can cause secondary scarring and skin pigment changes (Fleming and Smith 2000; McClinton 1993).

Venous malformations are the most common within the low-flow group. They are compressible with elevation. On radiographs, they may show phleboliths and skeletal hypertrophy. Initial treatment includes observation, splinting, and pressure garments. Pain and disfigurement may require surgical intervention. Severe hypertrophy can be treated with multiple epiphysiodesis when the digit has reached adult size. Sclerotherapy can be used as a definitive treatment or in preparation for surgery to limit intraoperative bleeding (McClinton 1993). Surgical treatment of large, diffuse lesions can be difficult and fraught with complications. Careful preoperative planning is needed to define the extents of the tumor, determined if staged resections are warranted, and if full thickness coverage is necessary.

Lymphatic malformations are associated with enlargement caused by fluid accumulation, not true growth. Difficulties with wrist and finger motion can occur. Infections with beta-hemolytic streptococcus are common (Walsh and Eady 2004). Compressive devices for those with wide extent and surgical excisions of smaller lesions are the mainstay of treatment.

Fast-flow malformations present early in life. They appear as painless masses and do not decompress easily with elevation. Other physical exam findings include warmth, pain, and palpable thrills or bruits. Digital ischemia caused by AV shunting or even high-output congestive heart failure can develop in large lesions.

Fast-flow malformations are further subdivided into types A, B, and C. Type A involves single or multiple AV fistulae, aneurysms, or ectasias of the arterial side of the circulation (Upton et al. 1999). Type B includes anomalies with small or large fistulae localized to a single limb artery. Stable flow parameters are present; few distal symptoms are noted. Type C malformations are the most concerning. Diffuse fistulae involving all limb tissues are present. They evolve, expand, and create a marked distal vascular steal phenomenon (Upton et al. 1999).

Initial treatment consists of compressive garments. If they are not worn, symptoms worsen with exercise. Malformations type A and B can be treated with multiple embolizations or careful surgical resection. Type C malformations are notoriously difficult to treat. Unrelenting pain caused by digital ischemia, ulceration, and lesion growth to involve larger portions of the limb can lead to a markedly high rate of amputations (Upton et al. 1999).

These are distinct from the previously described lesions. They can involve multiple vessels. They do not involute. Histologically, the cells lining the vessels may have mitoses that are concerning for malignancy. They tend to have local recurrence after resection. Excision is mainly done for diagnostic purposes or to control pain.

A range of fibrous tissue masses can be found in the upper extremity in children. The most commonly encountered are discussed in the subsequent sections.

This was described as a distinct entity among the fibromatoses by Reye in 1965. They are soft tissue tumors mostly present in early infancy. They are characterized by their almost exclusive occurrence on fingers and toes . The condition may occur as a single nodule or in multiple lesions on the fingers or toes, with the thumb and great toe always spared (Enzinger and Weiss 1995). “Kissing” lesions may occur on adjacent surfaces of digits (Netscher et al. 2009). One of the striking features of this tumor is the tendency to recur after surgical excision. Recurrence rates of 33–75 % have been reported (Ryman and Bale 1985). Wide excision, often with a skin graft or local flap for wound closure, can reduce the likelihood of recurrence (Netscher et al. 2009; Falco and Upton 1995). They have also been known to regress spontaneously (Burgert and Jones 1996). Lesions tend to often be associated with toe or finger deformities even after the tumors have regressed. The masses present as firm fleshy nodules, up to 2 cm in diameter on the fingers or ties. They present at birth or develop any time during infancy and early childhood. They tend to occur on multiple sites. Common locations include the dorsal and lateral aspect of fingers and toes, excluding the thumb and big toe (Enzinger and Weiss 1988). Deformities such as lateral deviation or flexion deformities are commonly associated findings that may persist after the nodule spontaneously regresses (Bloem et al. 1974).