Arteriovenous Malformations of the Temporalis Muscle: A Comprehensive Review

Abstract

Arteriovenous malformations of the temporalis muscle (TM-AVMs) are rare lesions commonly considered as a variant of scalp AVMs. A study was designed in order to analyze TM-AVMs features and to confirm them as a certain entity different from scalp AVMs. Seven TM-AVMs cases (5 from literature plus 2 from our database) were studied. Clinical, epidemiological, radiological, and therapeutic data were analyzed and compared to common scalp AVMs features. All TM-AVMs presented as large soft tumor-like masses on the temporal region (mean diameter: 6 cm). Pain was referred in half of cases, while overlying cutaneous stigmas were described only once. No masticatory malfunction was reported. TM-AVMs tend to appear in young patients (mean: 29 yr), commonly as longstanding and slow-evolving lesions (mean evolution time before diagnosis: 5 yr). All cases displayed a diffuse slow-flow blush on angiogram. All TM-AVMs were completely located within the TM, with no involvement of scalp or bone. The pathological analysis of all cases demonstrated the presence of striate muscular bundles intermingled with fairly mature arterial and venous vessels. No clearly distorted vessel was found within the TM-AVMs. Surgery was performed for all cases with complete removal. Preoperative embolization was done in 4 cases to reduce blood loss during surgery. No clinical/radiological recurrence was reported. Opposite to TM-AVMs, scalp AVMs commonly present as high-flow lesions with no evident tumor mass, mainly located in the subcutaneous tissue. TM-AVMs present clearly distinct features compared to scalp AVMs, for which they should be considered as a certain pathological entity and not as a variant of scalp AVMs.

Characteristics, Natural Course and Treatment of Intramuscular Capillary-type Haemangioma: A Systematic Literature Review

“…The features common to ICTHs are firm intramuscular lesions, which might occur at any age, but occur more frequently in young adults, appearing on imaging as intramuscular fast-flow lesions, without extension to the subcutaneous tissue or the underlying bone ( 2 ). They can easily be misdiagnosed as 4 main conditions: ( i ) intramuscular venous malformations (IVMs), characterized by slow flow on imaging, phleboliths, large venous vessels on microscopy, and the possibility of underlying bone changes ( 6 ); ( ii) high-flow anomalies with extension to the skeletal muscle, such as extracranial arteriovenous malformations (AVMs) ( 7 ); extra-renal angiomyolipomas (now called angiomyolipomas), which are tumours of uncertain differentiation whose diagnosis is based on microscopy observation of smooth muscles, thick-walled blood vessels and mature fat in varying proportions: they usually are located in subcutaneous tissue, with potentially intramuscular infiltration ( 8 , 9 ); ( iii ) phosphatase and TENsin homolog ( PTEN )-related hamartomatous tumour syndrome, which involves clinically heterogeneous disorders that share a germline mutation in PTEN and damage to the derivatives of the 3 embryonic laminae, leading to hamartomas, overgrowth and neoplasia ( 10 ); and ( iv ) highly vascularized intramuscular tumours, such as rhabdomyosarcomas ( 11 ).…”

Utility of manual venous compression during transvenous Onyx injection for a scalp arteriovenous fistula: illustrative case

“…6 Treatments of scalp AVFs include resection, endovascular embolization, and resection following embolization. [7][8][9][10] In the current era, endovascular therapy has been performed as an upfront treatment or adjunct to surgical excision through transarterial access, transvenous access, or directly punctured access. [8][9][10][11] When attempting transarterial embolization for scalp AVFs fed by STAs, possible complications such as scalp necrosis and alopecia are a concern.…”