Teaching Case

A young male presented with painful soft tissue lumps on bilateral shoulders. There was no history of trauma.

Ultrasound revealed multiple bilateral intramuscular ill-defined heterogeneous solid-appearing masses, a few of which showed slight predominantly peripheral vascularity.

Following this, pre and postcontrast MR of bilateral shoulders showed multiple intramuscular masses in the infraspinatus and deltoid muscles. The largest mass measured 7.8 x 2.1 x 2 cm in the right teres minor and 1.2 x 0.9 x 0.8 cm in the left deltoid. These lesions essentially showed iso to be slightly brighter than the muscle signal on T1 and were heterogeneously bright on fluid-sensitive sequences (T2/STIR). On gradient recovery images, few susceptibility artefacts were seen within suggestive of haemorrhage. The predominant enhancement pattern was moderate to intense heterogeneous peripheral enhancement with central necrosis/cystic changes. Surrounding oedema, extending into the adjacent musculature and along intervening muscular planes with some enhancement and susceptibility, were also noted. Imaging findings were indeterminate, and various possibilities, including mesenchymal lesions, metastasis, myxomas, inflammatory/infective processes, nodular and proliferative fasciitis/myositis and multiple inflammatory myofibroblastic tumours, were given. The patient underwent a biopsy of the right teres minor lesion, which was consistent with haemangioma.

Intramuscular haemangiomas (IMH) are benign vascular tumours accounting for less than 0.8% of all soft tissue tumours but are the most common type of deep intramuscular tumours [1].

IMH are extremely rare and often hard to diagnose accurately due to lack of specific symptoms, deep location, absence of obvious cutaneous change, slow growth rate, and size and shape variability with relatively low diagnostic rates of about 8% to 19% [2].

An IMH is a benign vascular tumour that contains neoplastic proliferation of endothelial cells and often occurs in skeletal muscle, mostly accompanied by intramuscular angiolipomas [3].

Retrospectively, in our case, ultrasound revealed multiple intramuscular heterogeneous predominantly hypoechoic lesions, which are nonspecific and can be seen in haemangiomas [4]. We used MRI to further study the masses due to its excellent ability to delineate deep seated lesions and discern the relationship with adjacent structures. Typically, on MRI, haemangiomas reveal an intermediate signal on T1-weighted images and a high signal on T2-weighted images [5]. Both of these features were evident with the lesions in our case. However, due to atypical features like lack of flow voids, typical avid peripheral nodular contrast enhancement, presence of muscle, and perimuscular oedema, haemangiomas were not considered in the differential diagnosis. Orly et al. [6], in their systematic review of intramuscular haemangiomas, showed that all cases showed avid contrast enhancement and flow voids. Secondly, perimuscular oedema and haemorrhage are rare in benign haemangiomas and more common in infectious or aggressive lesions. In the same review article, Orly et al. found no cases of intramuscular haemangioma involving the deltoid or the rotator cuff musculature. Guedes et al. [7] reported only one case of intramuscular haemangioma in the deltoid, which showed the absence of typical imaging features of vascular lesions with the presence of non-vascular elements, similar to our case.

Though the imaging features were nonspecific, we wish to report this case due to the conglomerate of rare features in terms of atypical features, for example, pattern of enhancement, multiplicity and perimuscular oedema and haemorrhage. To the best of our knowledge, we are the first to report a case of multiple bilateral intramuscular haemangiomas affecting the deltoid and rotator cuff musculature. Emphasis is not on diagnosis but rather on including haemangiomas in a list of differential diagnoses of multiple soft tissue lesions around the shoulder girdle or within skeletal muscles, especially in young individuals.