50-year-old Vietnamese male, with history of factor VIII deficiency haemophilia. The patient presents with multiple palpable masses within the right buttock region.
In the remote past, the patient had a left leg above knee amputation, secondary to extensive bleeding.
Oblique radiograph of the pelvis demonstrates a soft tissue convexity with multiple scattered calcifications.
Ultrasound image of the palpable mass in the right buttock demonstrates heterogeneous mass, with mixed isoechoic and hypoechoic regions.
CT images demonstrate multiple masses within the right gluteus maximus and medius, with multiple foci of coarse calcification, which are near the periphery of the masses. The masses are hyperdense at their periphery, with several nodular soft tissue densities centrally. There is lytic change involving the posterior right ilium adjacent to the right sacro-iliac joint, as well as the right sacrum. There is no associated periosteal reaction.
MR images again show the multiple lesions. All of the lesions demonstrate very low signal at their periphery on all imaging sequences, with susceptibility artifact on the gradient recalled echo images, consistent with haemosiderin deposition.
One of these lesions was aspirated under ultrasound guidance, returning a total of 450 ml of old blood.
Haemophilic pseudotumour is a rare complication of haemophilia, estimated to occur in approximately 1-2% of patients with severe disease [1]. It is seen almost exclusively in men, as the predisposing diseases of haemophilia A (factor VIII deficiency) and haemophilia B (factor IX deficiency) are both X-linked recessive diseases.
A pseudotumour is a chronic, encapsulated haematoma, and may initially occur either due to spontaneous or post-traumatic haemorrhage. The fibrous wall often maintains a blood supply, although the central portions of the lesion are avascular [2]. Repetitive bleeding at the level of the wall into the haematoma due to derangement of the clotting cascade leads to expansion and enlargement of this mass. This may result in erosion of the adjacent bone, or necrosis or denervation of adjacent muscle.
On radiography, pseudotumours appear as an area of increased soft tissue density, which may contain internal calcifications. There may be remodelling or frank destructive change of the adjacent bones.
On both ultrasound and CT, the appearance is widely variable, due to the possible different stages of haemorrhage within the lesion. Both anechoic and heterogeneously echoic collections have been noted on ultrasound. Similarly, pseudotumours of low, intermediate, and high density have all been reported [3].
On MR, the signal internally will vary on both the T1 and T2 weighted images due to the evolution of the blood products. However, pseudotumours have a characteristic rim of dark signal on all imaging sequences, due to the presence of the fibrous and haemosiderin-laden wall. On MR imaging, the differential diagnosis is relatively limited, due to the characteristic low signal rim. A rare mimic of this lesion is the aneurysmal bone cyst of soft tissue. [6]
The management of these lesions is controversial. Prevention of these lesions by factor replacement is effective [4]. Once the lesion is present, many forms of therapy have been used, to variable success, including: irradiation, embolisation, percutaneous evacuation with instillation of fibrin seal, surgical resection, and as a last resort, amputation [5].
Hemophilic pseudotumour.
Based on the X-ray, ultrasound, CT, and MRI images provided by the patient, multiple masses with relatively well-defined but irregular shapes can be observed in the right buttock soft tissue:
Overall imaging features suggest chronic hemorrhagic encapsulated lesions. Considering the patient’s background of coagulopathy (hemophilia), these findings are consistent with hemophilic pseudotumors.
Based on the patient’s history (severe factor VIII deficiency/hemophilia A) and the imaging characteristics above, the primary considerations include:
Considering the patient’s severe hemophilia A (factor VIII deficiency), long-term repeated bleeding history, and imaging findings of multiple thickly encapsulated soft tissue masses showing complex signals consistent with blood breakdown products, the most likely diagnosis is:
Hemophilic Pseudotumor.
If there is any diagnostic uncertainty, additional testing of factor VIII activity, coagulation function, or a biopsy/puncture examination (under adequate correction of coagulation) may be considered to exclude malignancies. However, given the typical clinical history and imaging features, the diagnosis can be established with reasonable confidence.
Since the patient has undergone high-level amputation of one lower limb and is at high risk of recurrent bleeding, rehabilitation activities must be undertaken with caution and gradually progressed. After adequate factor replacement and bleeding control, the following FITT-VP principles may be considered:
Should localized swelling, significant pain worsening, or any suspected bleeding occur during training or daily activities, stop immediately and seek medical review.
This report is a reference analysis based on current imaging and clinical information and does not replace in-person consultation or professional medical advice. If you have additional concerns or if symptoms worsen, please seek medical attention promptly.
Hemophilic pseudotumour.
