Menoufia Medical Journal

: 2019  |  Volume : 32  |  Issue : 4  |  Page : 1528--1530

Synovial haemangioma of the knee joint diagnosed on magnetic resonance imaging: a rare case report

Ishan Kumar, Ashish Verma, Pramod K Singh 
 Department of Radiodiagnosis and Imaging, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India

Correspondence Address:
Ashish Verma
Department of Radiodiagnosis and Imaging, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221 005, Uttar Pradesh


Synovial haemangioma is an extremely uncommon condition which presents with nonspecific clinical symptoms. The diagnosis, if delayed, can ensue early arthritis, early epiphyseal fusion, and growth abnormality. As it resembles various benign cystic lesions on MRI, utility of contrast MRI, Doppler study, and presence of high index of suspicion are crucial in the diagnosis. We report a case of synovial haemangioma in a 45-year-old female patient, in which the diagnosis was missed on initial MRI.

How to cite this article:
Kumar I, Verma A, Singh PK. Synovial haemangioma of the knee joint diagnosed on magnetic resonance imaging: a rare case report.Menoufia Med J 2019;32:1528-1530

How to cite this URL:
Kumar I, Verma A, Singh PK. Synovial haemangioma of the knee joint diagnosed on magnetic resonance imaging: a rare case report. Menoufia Med J [serial online] 2019 [cited 2020 Apr 6 ];32:1528-1530
Available from:

Full Text


Haemangiomas are benign neoplasms of vascular origin with endothelial proliferation, accounting for 7% of all benign soft tissue masses in the body [1]. These hamartomas are now known to originate as a part of disordered mesodermal proliferation during differential development of primitive mesenchyme into various derivatives. Further, mesodermal stem cells are present in most organs of the body including the articular synovium and can lead to the formation of 'synovial haemangioma' under rare circumstances [2]. These lesions usually present with nonspecific articular pain and stretching sensation and the diagnosis is obtained on imaging. The aim of this report is to describe the specific imaging features of this rare pathology on multiple imaging modalities which when put together may exclude the requirement for tissue biopsy for establishing the diagnosis.

 Case Report

A 45-year-old female patient presented with complaints of pain and focal swelling in the posterior aspect of the right knee joint for the past 3 years. The swelling was firm, nonpulsatile and nonmobile with no alterations in the colour, texture and temperature of the overlying skin. The patient had previously undergone radiography and noncontrast MRI of the knee joint at an outside institute. Radiography was reported as normal and the MRI report was suggestive of mild joint effusion in the posterior aspect of the knee joint; however, the images were not available for review. The patient's physical examination has shown a palpable swelling in the posterior aspect of the knee joint without any tenderness. No other abnormality was detected.

The patient was referred to the Radiology Department for assessment of the knee where a plain radiograph of the knee joint was performed in anteroposterior and lateral projections. A close scrutiny of the lateral radiograph of the knee revealed two calcific foci posterior to the inferior femoral margin adjacent to the medial femoral condyle. The visualised bones were normal. A differential diagnosis of synovial osteochondromatosis and a calcified mass was considered and the patient was taken up for ultrasound. Sonography showed a well-circumscribed soft tissue mass lesion in the superior aspect of the popliteal fossa. There was no erosion of adjacent osseous and soft tissue structures. Colour Doppler interrogation of the mass showed multiple vascular channels within the lesion with both arterial and venous waveforms. Based on the plain radiograph and Doppler sonography an initial working possibility of benign vascular neoplasm was kept and a suspicion of synovial haemangioma was mentioned to the treating orthopaedician. A differential diagnosis of synovial sarcoma was however also considered and a repeat MRI was performed on a 1.5 T superconducting system (Magnetom Avanto; Siemens Medical Systems, Erlangen, Germany) with addition of contrast-enhanced sequences. MRI showed a lobulated lesion measuring 18 × 10 mm in the posterior aspect of the intercondylar region, overlying the posterior cruciate ligament. The lesion was isointense to the muscles on T1-weighted images and strongly hyperintense on T2-weighted sequences with multiple T2 dark lace-like septations [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e. Gadolinium-enhanced T1 image showed strong and homogeneous enhancement of the whole lesion. No obvious bony erosion/involvement was seen. The lesion was reported as haemangioma on MRI and the patient was referred to the General Surgery Department where an open excision of the lesion was performed. Histopathology revealed synovial haemangioma.{Figure 1}


Synovial haemangioma is an extremely rare condition with less than 250 case reports in the present literature. Pathologically, they are defined as benign vascular lesions arising from structures lined by synovium, that is, joint cavity, bursal space and tendon sheaths [3],[4]. They are classified into four categories: cavernous, capillary, arteriovenous and venous types with the cavernous type being the most common (50%) [5],[6]. On the basis of the extent of involvement, these lesions are divided into diffuse and circumscribed types, which is more useful for the surgeons [7]. On the basis of the relationship to joint cavity, they are classified into juxtaarticular, intra-articular and intermediate types [8].

Knee is the most common site of involvement followed by the elbow, wrist, ankle and the temporo-mandibular joint [8]. In the knee, haemangiomas most commonly occur in the anterior compartment with only minority occurring in infrapatellar location [5]. To the best of our knowledge, there are only a few previously described case reports of synovial haemangiomas in the posterior compartment of the knee [9],[10]. Due to nonspecific clinical features and presenting symptoms, the diagnosis can be delayed up to years. Patients most commonly present with symptoms of pain and swelling followed by painless swelling and uncommonly intra-articular haemorrhage, limited range of motion and pseudolocking [9],[11]. However, it is imperative to recognise this condition early on as later during the course of disease arthritis, early epiphyseal fusion and growth abnormalities can occur.

Plain radiograph is usually the first modality to evaluate knee pain. Plain films are interpreted as normal in half the cases and show a vague soft tissue density in close relation to the bone in the other half which may be interpreted as joint effusion or a mass lesion. Phleboliths, when present, are a relatively specific sign; however, it can be mimicked by synovial osteochondromatosis, loose bodies, osteochondritis dissecans, or small fracture. [12],[13]. When the diagnosis is delayed, recurrent haemorrhage in the joint may produce haemophilia-like arthritis [14]. Other roentgenographic signs such as advance maturation of epiphysis, cortical erosion, and osteopenia can be present in minority of cases [12]. Ultrasound is a relatively inexpensive tool to evaluate soft tissue lesions. Sonography can be utilised to characterize the lesion and typically shows a lobulated homogeneous soft tissue lesion with embedded calcifications. Extension into the joint cavity can be demonstrated on careful examination. Colour Doppler scan showed densely distributed vessels within the mass which can show arterial, venous or both spectral waveforms on pulsed wave imaging.

On MRI, these lesions demonstrate a lobulated mass which is isointense to the muscle on T1-weighted images and markedly hyperintense on T2-weighted sequences with multiple intralesional T2 dark septations. The areas of high T1 signal can also be obtained due to the intratumoral fat or blood [12]. Marked T2 signal intensity is due to pooling of the stagnant blood within the lesion and T2 dark septations are thought to represent fibro-fatty septa and vascular channels [5]. Small, rounded signal voids can also be uncommonly identified, consistent with phlebolithis [8]. Fluid-fluid levels also have been reported on T2-weighted sequences compatible with intralesional haemorrhage [8]. The lesion may resemble ganglion cyst, lymphangioma, or even joint effusion, which can be distinguished by using contrast MRI. On postcontrast T1 sequences show strongly and homogeneously enhancing lesions unlike joint fluid or ganglion cyst which do not show contrast uptake. A scant and patchy, peripheral enhancement has also been reported in synovial haemangiomas [13]. Gadolinium-enhanced MRI also provides better delineation of the margins of the lesion from the intra-articular effusion and demonstration of extraarticular involvement which is necessary for surgical planning. An important radiological and histopathological differential diagnosis is pigmented villonodular synovitis (PVNS), which can also present as a cystic lesion in juxtaosseous locations [4]. However, PVNS shows areas of dark T2 signal unlike haemangiomas and on postcontrast images PVNS shows enhancement of the synovial lining and not the whole tumour as seen in haemangiomas [8]. Other important differential diagnoses are synovial sarcomas which are usually characterised by bony erosion and signal intensity resembling soft tissue rather than cystic signal on T2-weighted sequence. In our case, the patient underwent MRI from an outside institute, but retrospectively, we believe that the diagnosis was initially missed because a contrast MRI was not performed and the lesion was reported as joint effusion. In our institute, we could recognise the phleboliths on radiography and the soft tissue nature of the lesion on ultrasonography which enabled us to keep this rare lesion early on in our differential consideration.

Surgical excision with partial or total synovectomy is the treatment for these tumours. Arthroscopic approach is preferred for a well-circumscribed haemangioma and open surgical technique is employed for diffuse lesions. Other proposed treatment strategies include embolisation, holmium, laser ablation, cautery and freezing [10],[12].

In conclusion, we wish to emphasise that synovial haemangiomas should be considered as one of the differentials whenever a benign appearing lesion is encountered within the knee joint capsule. The appearances compiled from a combination of multiple imaging modalities seem reasonably confirmatory, and obviated the need of invasive histopathological evaluation in the present case. This may prove crucial for deciding the line of management of these lesions.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Suh JS, Hwang G, Hahn SB. Soft-tissue hemangiomas: MR manifestations in 23 patients. Skeletal Radiol 1994; 23:621–625.
2Bouchut GE. Tumeur erectile de l'articulation du genou. Gaz Hop 1856; 29:379–381.
3Kenneth D, Vinh TN, Sweet DE. Synovial hemangioma: a report of 20 cases with differential diagnostic considerations. Hum Pathol 1993; 24:737–745.
4Rajni, Khanna G, Gupta A, Gupta V. Synovial hemangioma: a rare benign synovial lesion. Indian J Pathol Mircrobiol 2008; 51:257–258.
5Wang MT, Chen CK, Yeh LR, Chen JC, Tzeng WS, Chen IC, et al. Synovial hemangioma of the knee joint: a case report. Chin J Radiol 2008; 34:239–243.
6Stout AP. Hemangioma-endothelioma: a tumor of blood vessels. Ann Surg 1943; 118:445–464.
7Bennet GE, Cobey MC. Hemangioma of joints: report of five cases. Arch Surg 1939; 38:487–500.
8Sanghi AK, Ly JQ, McDermott J, Sorge DG. Synovial hemangioma of the knee: a case report. Radiol Case Rep 2007; 2: 33–36.
9Dileep KS, Kanakaraddi SV, Vidyasagar JVS, Radha S, Aroor AR. Intra-articular synovial hemangioma of knee overlying posterior cruciate ligament – a case report. Nitte Uni J Health Sci 2012; 2:42–44.
10Dunet B, Tournier C, Pallaro J, Boullet F, Fabre T. Arthroscopic treatment of an intra-articular hemangioma in the posterior compartment of the knee. Orthop Traumatol Surg Res 2014; 100:337–339.
11Devaney K, Vinh TN, Sweet DE. Synovial hemangioma: a report of 20 cases with differential diagnostic considerations. Hum Pathol 1993; 24:737–774.
12Vakil-Adli A, Zandieh S, Hochreiter J, Huber M, Ritschl P. Synovial hemangioma of the knee joint in a 12-year-old boy: a case report. J Med Case Rep 2010; 4:105.
13Sanchez TR, Wong S, Swischuck L, Carmichael K. Synovial hemangioma in a 2-year old mimicking synovial osteochondromatosis. Open J Rad 2012; 2:22–24.
14Resnick D, Oliphant M. Hemophilia-like arthropathy of the knee associated with cutaneous and synovial hemangiomas. Report of 3 cases and review of the literature. Radiology 1975; 114:323–326.