Ischaemic fasciitis: unusual localisation

Clinical History

We describe a 65-years-old male patient, who came to our department with an asymptomatic mass in the right axilla. On clinical history, the patient reported a previous surgical intervention in the same site, two years before, for lipoma excision.

Imaging Findings

On US, a well defined mass, localised deeply in the right axillary subcutaneous tissue, just above the axillary vein, measuring 4 x 3 cm, was detected.
Subsequently CE-MR was performed. On MR the lesion appeared as a well defined mass with heterogeneous signal on T2- weighted image, and isointense on T1-weighted image. On fat suppressed T2 weighted image, the mass had heterogenous signal with multiple low signal intensity portions. After gadolinium administration, we observed a heterogeneous enhancement, with low signal central areas suggestive of necrosis. Core biopsy was not performed because of the lesion’s location, so the patient underwent excisional biopsy. At pathology, a central zone of fibrinoid necrosis and fat necrosis surrounded by vessels and proliferating fibroblasts was detected. Macroscopically the lesion was ill-defined, tan-white, elastic and non- ulcerated. Therefore diagnosis of ischaemic fasciitis was established.

Discussion

Ischaemic fasciitis is caused by fibroblasts/myofibroblasts proliferation set in a myxoid stroma. This condition usually occurs in aged, debilitated, bed-ridded patients or after trauma [1]. It is considered as a reactive process, which occurs in the areas of pressure over the bones.
The pathogenesis seems to include intermittent ischaemia, an association with local mechanical pressure or trauma cannot be found in all cases [2-3].
CLINICAL PERSPECTIVE
Common findings are a poorly-circumscribed, non ulcerated, hard elastic, asymptomatic mass, localised deeply in subcutaneous tissues, which often involve muscles, tendons and fascia. According to its rapid growth, it could be misinterpreted as a sarcoma or other malignant soft tissue tumour [5].
IMAGING PERSPECTIVE
On US, a mass with hyperechoic rim surrounding an hypoechoic central area can be depicted.
On MRI, it appears as an isointense mass on T1 sequence, with low signal central area and a high signal intensity rim on T2w sequences. After contrast agent administration it usually shows a heterogeneous signal [5, 6].
CASE MANAGEMENT
Core biopsy was not performed because of lesion’s position immediately above main axillary vessels.
Patient underwent surgery with associated lymphectomy.
Histological analysis confirmed the clinical diagnosis.

Differential Diagnosis List

Final Diagnosis

Fasciitis with the characteristics of ischaemic type.

URL:	https://www.eurorad.org/case/10605
DOI:	10.1594/EURORAD/CASE.10605
ISSN:	1563-4086