Neck mass - the power of radiology to avoid biopsy when it is not necessary!

Clinical History

A 38-year-old woman had previously presented to the emergency department years earlier with left submandibular swelling and blushing/hypertrophy of the left palatine tonsil, interpreted and treated as acute tonsillitis. Imaging studies were not performed. Past medical history included depression. She represented with the same complaint, despite treatment with analgesics/antibiotics.

Imaging Findings

Doppler US (Fig. 1) was performed in order to establish the presence of fast-flowing vessels and permit the differentiation of low from fast-flow lesions. In the absence of fast-flowing vessels it is vital to determine whether hypoechoic areas contain blood. If so, they usually represent venous malformations. Thrombi, phleboliths and fluid levels may be present within vascular spaces. Ultrasound showed a hypoechoic lesion with no flow on colour Doppler.

Non-contrast CT (Fig. 2) showed small hyperdense foci within a left level II lesion, displacing the submandibular gland anteriorly. A previous contrast-enhanced neck CT (not shown) did not demonstrate enhancement due to intralesional slow flow, masking the correct diagnosis. A subsequent neck CT examination (Fig. 3-5) showed an isoattenuating lesion between the left carotid arteries, with slow centripetal enhancement (another pitfall).

MR images (Fig. 6-8) confirmed a hyperintense T2-weighted lesion occupying left mucosal pharyngeal, parapharyngeal and carotid spaces.

Discussion

The majority of soft tissue tumours until the age of 45 are benign [1, 2]. Vascular malformations are among the most common.

The International Society for the Study of Vascular Anomalies (ISSVA) has developed a currently accepted classification [3].

Vascular lesions can be divided into vascular malformations (non-neoplastic) and vascular tumours.

Vascular malformations are sub-categorised according to dynamics [4]. The most common, venous and lymphatic, do not have fast flowing vessels, but often the vascular spaces are interspersed by fat [5].

The commonest locations of venous malformations (VM) are the head and neck, extremities and trunk [6].

Clinical presentation depends on the depth, size and extent of the lesion, all critical findings especially in the head and neck. Enlargement, thrombosis and pain are common [7].

Accurate diagnosis and classification of a vascular anomaly are decisive because treatment planning depends on the type of malformation.

Clinical history is important in establishing an accurate diagnosis and should never be overlooked. In many circumstances it provides key information to suggest a specific diagnosis.

VMs occurring in superficial areas are usually easy to diagnose by clinical examination. However, those lesions that are deep in the face and neck are often challenging through clinical examination alone.

Doppler US provides information about the degree of vascularity of a lesion. VM appear as hypoechoic or heterogeneous lesions in the large majority of cases [8]. However, US has the disadvantage, particularly in the deep spaces of the neck, that restricted penetration and absent flow is common in those with very slow flow [9]. Superficial VM may be obscured by compression during the ultrasound examination, but compressibility itself is a useful diagnostic feature when observed.

MR allows better delineation of lesion extent and superior definition of anatomical boundaries [7].

VM are usually hypoattenuating on CT, hypointense or isointense on T1W and hyperintense on T2W. Signal heterogeneity may be evident in cases of haemorrhage or thrombosis. Gradual in-filling with contrast over time is typical.

The extent of the malformation should be assessed on T2W images. T1W images can show internal and surrounding fatty change. Gadolinium contrast administration is vital to evaluate enhancement. Gradient-echo T2* may be used to demonstrate calcification or haemosiderin.

Treatment options in symptomatic lesions, as in our case, include surgery, laser therapy, sclerotherapy, or a combination of these. Large / deep lesions may require multiple treatment sessions and remain challenging, although symptoms can generally be controlled.

Differential Diagnosis List

Final Diagnosis

Cervical venous malformation

URL:	https://eurorad.org/case/14664
DOI:	10.1594/EURORAD/CASE.14664
ISSN:	1563-4086