Healthy 76-year-old man, with no antecedent trauma, presented with a painful, slow-growing, soft tissue mass of several years duration, in the internal compartment of the right ankle.
Magnetic resonance imaging (MRI) showed a well-defined subcutaneous soft tissue mass, measuring 5 x 3.5 x 5 cm, localized in the internal compartment of the right ankle, superficial to the tibialis posterior and the flexor digitorum longus tendons. No signs of invasion of the tendons or bone were seen.
The mass had heterogeneous signal intensity, being predominantly isointense compared to skeletal muscle on T1-weighted images (T1-WI) and hyperintense on fat-suppressed T2-weighted images (FS T2-WI), with hyperintense and isointense areas intermingled.
A well-defined hypointense peripheral rim was seen on both T1-WI and FS T2-WI. Several serpentine structures with low signal intensity on T1-WI and high signal intensity on FS T2-WI were also observed, abutting the periphery of the mass.
After intravenous administration of contrast material, the tumour showed strong and heterogeneous enhancement on T1-WI, with hyperintense areas on FS T2-WI displaying a greater degree of enhancement.
Angioleiomyomas, also known as vascular leiomyomas, are rare solitary benign tumours, thought to arise from the tunica media of veins. [1]
They can occur in the dermis, subcutaneous fat or fascia, and can be located anywhere in the body, appearing more frequently in the extremities, especially in the lower limbs. [2, 3]
They have a slight female predominance (male to female ratio: 1:1.7 - 1:2.2) and occur more frequently in the fourth to sixth decades of life (age range: 11-84 years). [2, 3]
Angioleiomyomas are usually small, firm, mobile, slow-growing masses. Pain is described in about 60% of patients and is thought to be related to smooth muscle contraction, resulting in local ischaemia. [1]
Pathologically, angioleiomyomas can be classified in three types: solid, venous and cavernous. Apart from smooth muscle bundles and blood vessels, these tumours may also contain areas of hyalinization, fat or calcifications. [3, 4]
The diagnosis of angioleiomyomas is usually made post-operatively. However, ultrasound, and especially MRI, can provide valuable preoperative information. [5, 6]
On ultrasound examination, these tumours demonstrate well-defined margins, oval shape and hypoechoic homogeneous structure. Colour Doppler evaluation shows hypervascularity. [7, 8]
On T1-WI, angioleiomyomas are well-demarcated masses, with either homogeneous or heterogeneous signal, isointense to skeletal muscle. On T2-WI they usually exhibit high signal intensity, with mixed areas of hyper- and isointensity (the former corresponding to smooth muscle and vessels; the latter to areas of fibrous tissue). Hyperintense areas on T2-WI generally show strong enhancement after intravenous administration of contrast material, while isointense areas are non-enhancing. A peripheral hypointense rim is frequently seen on both T1-WI and T2-WI and corresponds pathologically to a fibrous capsule. Peripheral vascular structures abutting the mass may also be identified and constitute a clue for the diagnosis. [4, 5]
The pre-operative differential diagnosis is vast and may include neurogenic tumours, subcutaneous leiomyosarcoma, haemangioendothelioma and haemangiopericytoma. Although neurogenic tumours are typically well-defined masses with hyperintense signal on T2WI, they usually do not exhibit peripheral tortuous vessels. [5] The differential diagnosis with subcutaneous leiomyosarcoma is challenging. The growth rate of the mass (slower in angioleiomyomas) may aid in clinical discrimination. Haemangioendotheliomas and haemangiopericytomas are typically more heterogeneous tumours, which may contain haemorrhagic areas. [8]
Angioleiomyoma should be considered as a possible diagnosis whenever a sharply-demarcated subcutaneous mass is seen in the lower extremities, with isointense signal on T1-WI, high signal on T2-WI, and strong enhancement. The identification of tortuous vascular structures abutting the mass corroborates the diagnosis. [5, 9]
Angioleiomyoma
The patient is a 76-year-old male. An oval-shaped soft tissue mass with well-defined margins is noted in the medial compartment of the right ankle. Based on the provided MRI sequences:
Overall, the lesion presents as a localized soft tissue mass with an intact capsule, consistent with the characteristics of a benign vascular tumor.
Based on the patient’s clinical presentation (no obvious history of trauma, pain, and a slowly enlarging soft tissue mass) and the imaging features (well-defined borders, hyperintensity on T2, marked enhancement, and associated vascular structures), the following diagnoses can be considered:
Taking into account the patient’s age, the typical location in the lower extremity, clinical presentation, and the MRI features of hyperintensity, well-defined margins, significant enhancement, and peripheral vascular structures, the most likely diagnosis is:
Angioleiomyoma.
If further confirmation is necessary, postoperative pathological examination and immunohistochemical staining (e.g., positive for smooth muscle actin and vimentin) can provide a definitive diagnosis.
During postoperative or conservative management, an individualized and gradual approach should be followed to formulate a rehabilitation training plan:
FITT-VP Principle (Frequency, Intensity, Time, Type, Volume, Progression):
Disclaimer:
This report is a reference-based analysis drawing on current imaging and medical history information. It is not a substitute for in-person consultation or the advice of a professional physician. In case of any doubt or worsening symptoms, please seek timely medical attention and follow the recommendations of a specialist.
Angioleiomyoma
