Prepared by Dr. Justin Q. Ly at the Department of Radiology
and Nuclear Medicine, Wilford Hall Medical Center, San Antonio,
TX.
CASE SUMMARY
The patient, a 20-year-old woman, presented to the clinic with
left mid-foot pain and swelling. She denied trauma and her medical
history was unremarkable. On physical exam, a nontender soft tissue
prominence was noted over the dorsal aspect of the foot. There was
no evidence of ecchymosis or cellulitis. Radiographic examination
of the left foot was negative except for the presence of mildly
prominent soft tissue over the mid-foot dorsum (Figure 1). Because
there remained clinical suspicion for a mass, magnetic resonance
(MR) imaging was subsequently performed.
DIAGNOSIS
Soft tissue hemangioma of the foot
IMAGING FINDINGS
On axial T1-weighted imaging, a poorly defined, lobulated mass
of intermediate signal intensity is noted to involve the plantar
aspect of the foot, localized to the area between the first and
second metatarsals (Figure 2). On axial T2-weighted imaging with
frequency selective fat suppression (Figure 3), the lobulated mass
is predominantly high in signal intensity, with scattered areas of
low signal representing clots, hemosiderin, smooth muscle, and
dense fibrous tissue. The coronal fat-suppressed T1-weighted image
following gadolinium administration reveals a mild increase in
homogeneity of the hyperintense mass with improved visualization of
the serpiginous or serpentine pattern of enhancement (Figure 4)
that is characteristic of soft tissue hemangiomas.
Excisional biopsy was performed on this patient, with histologic
findings diagnostic of soft tissue hemangioma of the capillary
type.
DISCUSSION
Soft tissue hemangiomas are one of the most common tumors of
childhood and comprise 10% of all benign vascular tumors.
1
They are composed of vascular elements embedded in fibrofatty
tissue and can arise from cutaneous, intermuscular, synovial,
subcutaneous, intramuscular, or mixed tissues. The most accepted
classification system is based on the histologic appearance of the
vessels and includes the following subtypes: capillary, cavernous,
venous, arteriovenous, and mixed.
1,2
Clinical manifestations may include pain, the presence of a mass,
soft tissue swelling, subcutaneous discolorations, and less
frequently, neurologic symptoms secondary to impingement of a nerve
bundle. These symptoms may be present for years before a diagnosis
is made. Superficial soft tissue hemangiomas have a predilection
for the head and neck while deep-seated hemangiomas appear more
frequently in the trunk and lower extremities.
3
Malignant degeneration is extremely rare. Moreover, hemangiomas
do not metastasize, but rather proliferate or involute with time.
Conventional radiography of the affected area is usually the
initial diagnostic study obtained in patients suspected of having a
soft tissue mass and will often reveal an ill-defined soft tissue
prominence or mass. In many cases, the radiographs are normal,
however. The other major soft tissue finding is phleboliths, which
can occur in 20% to 67% of cases.
3-5
Although a very specific radiographic sign for soft tissue
hemangiomas, phleboliths are not very sensitive.
6
When the hemangioma is abutting an osseous structure, cortical
change or periosteal reaction is possible. Due to its superior
ability to image soft tissue structures and multiplanar capability,
MR imaging is the recommended follow-up study to further
characterize a soft tissue mass. T1-weighted imaging usually shows
a heterogeneous mass of intermediate signal with lacy-appearing
interspersed high signal areas representing interspersed fat
7,8
; fatty overgrowth is characteristic of soft tissue hemangiomas.
T2-weighted imaging shows a predominantly high signal intensity,
heterogeneous mass. Interspersed areas of signal void can occur on
both T1- and T2-weighted imaging and may represent relatively high
velocity blood flow, whereas rounded foci of low signal are due to
thrombi, phleboliths, or dense fibrous tissue.
8
Contrast-enhanced images may demonstrate enhancement in a
serpiginous manner. Ultrasound is less helpful because of the low
specificity of the hyperechogenic mass commonly found. Computed
tomography (CT) is also less helpful diagnostically because of its
inadequate soft tissue contrast. Therefore, CT should be reserved
for evaluation of the possibility and extent of osseous
involvement. The definitive diagnosis is determined by biopsy.
Treatment depends on the location, size, and subtype of the soft
tissue hemangioma. Superficial capillary hemangiomas are often
treated conservatively as their natural history is involution with
time. For deep-seated soft tissue hemangiomas, however, wide local
excision is the optimal management in order to prevent recurrence.
Angiography is rarely used therapeutically, but is sometimes used
for surgical planning, to improve hemostasis during the actual
operation, and to demonstrate any feeding and draining vessels.
6