Clinical History
A 59-year-old man with history of non-Hodgkin lymphoma and peripheral venous insufficiency presents with a palpable mass in the right tibial shaft associated with intermittent pain. He had no previous history of lower extremity trauma or infection. Radiography and magnetic resonance of the lower extremity were performed.
Imaging Findings
Radiography of the lower extremity showed two small cortical defects in the middle third of the tibial diaphysis, one located in the anterior cortex and the other in the lateral cortex, cranially to the former. Each one was connected to a heterogeneous area in the medullary region, through a small groove. Additionally, a small soft tissue mass was seen in the pre-tibial region, abutting the anterior cortical defect. No periosteal reaction was documented.
MR images showed a tubular structure originating in the superficial venous system, extending posteriorly through the anterior tibial diaphyseal cortex into the medullary canal and then perforating the lateral tibial diaphyseal cortex to connect with the deep venous system. This tubular structure had low signal intensity (SI) on T1, high SI on T2 and avid enhancement on T1 with gadolinium.
Multiple varices were seen in pre-tibial sub-cutaneous tissue. No signs of thrombophlebitis or osteomyelitis were present.
Discussion
Leg varices have high prevalence, afflicting around 10-40% of the world’s population [1, 2]. It is one of the most prevalent chronic conditions in which treatment has a high impact in health care systems.
Intraosseous venous anomalies are rare, with just a few cases described in the literature [2]. The cause of this pathology is unknown. In physiologic conditions venous flow in long bones occurs in both centripetal and centrifugal ways, the former being predominant. Boutin et al postulated that centripetal transcortical venous flow could be heightened secondary to venous insufficiency, venous hypertension, or both. These will make the flow mainly centrifugal, which can be responsible for intraosseous venous anomalies. [1] Conversely, patients with intraosseous venous anomalies are at risk for varices and deep venous thrombosis [1, 3].
Patients are invariably symptomatic and have peripheral venous insufficiency [2].
Management depends on the cause and site of the pathologic venous insufficiency. Most of the assessment is made clinically and with ultrasound examinations, but few are studied with conventional radiographs and MRI [1].
Conventional radiography usually shows cortical interruption in the middle third of the tibial diaphysis and a groove connecting the cortical defect with an intramedullary lytic lesion. Another typical finding is a soft tissue mass near the cortical defect representing subcutaneous varices.
MRI finding corroborate the radiography findings, showing a small vein arising from the superficial venous system, perforating the cortical bone, crossing the medullary bone as a tortuous vessel, exiting through the nutrient canal and draining in the deep venous system.
Treatment can be either surgical or nonsurginal. Surgical treatment is preformed through ligation of the venous anomaly. Some authors advocate a nonsurgical approach, usually sclerotherapy [4], as a safe and alternative method to treat anomalies with slow blood flux documented in venography [1, 3].
The characteristic triad of findings in patients with anomalous intraosseous venous drainage are: symptom-producing pretibial varices, a cortical defect in the anterior aspect of the midtibia and an enlarged intraosseous vein and nutrient canal [1].
Differential Diagnosis List
Anomalous intraosseous venous drainage
Prominent nutrient groove in an otherwise normal tibia
Arteriovenous malformations
Venous malformations
Haemangiomas
Osteomyelitis
Haematoma
Final Diagnosis
Anomalous intraosseous venous drainage
