Angioleiomyomas, also known as angiomyomas or vascular leiomyomas, are benign pericytic or perivascular soft tissue tumors.
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Epidemiology
Angioleimyomas are rare and have been observed in a wide age range with a peak in the 4th to 6th decades of life. Generally, women are more commonly affected 1-4. They account for up to 5% of all benign soft tissue neoplasms 3.
Diagnosis
Diagnostic criteria according to the WHO classification of soft tissue and bone tumors (5th edition) 1:
essential: well-circumscribed tumor composed of cytologically bland smooth muscle cells showing concentric growth around vascular channels of varying caliber
Clinical presentation
The usual presentation is a firm slow-growing nodule, more than half of the tumors are associated with pain 1-3.
Pathology
Angioleiomyomas typically originate in the skin and subcutaneous tissues and mainly constitute well-differentiated perivascular smooth muscle cells aligned around multiple variably-sized vascular channels 1. There are descriptions of a fibrous pseudocapsule 2,5.
Etiology
There is no clear established etiology for angioleimyomas. Venous stasis and minor trauma have been proposed as potential causative factors 1.
Location
Angioleiomyomas are most frequently found in the subcutaneous tissues and dermis and rarely in the deep soft tissues of the following locations 1-5:
lower and upper extremities
head and neck region
trunk
Macroscopic appearance
Macroscopically angioleiomyomas are usually circumscribed solitary relatively small masses <3 cm at the time of their presentation and feature a grayish-white to brown appearance 1,4.
Microscopic appearance
There are three different histological subtypes of angioleiomyomas subject to their vascular morphology (solid, venous and cavernous) with the following features 1:
fascicles of bland, well-differentiated smooth muscle cells
interposed vascular channels of a variable calliber
possible myopericytoma-like elements
might show adipocytic metaplasia, prominent hyalinization or uncommonly calcification
The subtypes do not seem to have any clinical significance.
Immunophenotype
Immunohistochemistry stains are usually positive for smooth muscle actin, calponin and h-caldesmon as well as variably positive for desmin 1.
Radiographic features
Imaging findings are generally non-specific 2,3:
usually well-defined, oval, lobulated or round masses
expansile growth
sometimes with cortical scalloping if adjacent to bony structures
Ultrasound
On ultrasound angioleiomyomas have been described to display the following characteristics 3,4:
echotexture: homogeneous in the majority of cases, heterogeneous in about a fourth
usually hypoechoic or hypoechoic and isoechoic
might show hypoechoic protrusions at the ends of the mass
posterior acoustic enhancement
vascular flow signal on color Doppler
no septations
CT
CT will probably show a well-defined and otherwise unspecific cutaneous or subcutaneous soft tissue density mass. There might be calcifications.
MRI
In addition to the general imaging features a peripheral low-signal intensity rim corresponding to a fibrous pseudocapsule with adjacent vascular structures have been described on MRI in addition to the following signal characteristics 2-5:
T1: isointense or hyperintense to muscle
T2: heterogeneous and slightly hyperintense to muscle
T1 C+ (Gd): homogenous to heterogeneous enhancement, rarely only peripheral
Radiology report
The radiological report should include a description of the following:
form, location and size
tumor margins and transition zone
distance from the muscular fascia
contact to bones or neurovascular structures
Treatment and prognosis
Management is primarily surgical excision. Angioleiomyomas are benign and recurrence is rare 1-5.
History and etymology
Angioleiomyomas were first described in 1937 by the American surgical pathologist Arthur Purdy Stout (1885-1967) 6,7.
Differential diagnosis
Conditions that can mimic the presentation and/or appearance of angioleiomyomas include 2-4:
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