13-year-old girl presented with history of pain in the left thigh for the past 25 days. No history of trauma or fever. Recent X-ray and CT reports revealed lytic lesion in the femur. Past medical history revealed that she had been diagnosed with congenital afibrinogenaemia shortly after birth because of bleeding from the umbilicus.
Cystic intramedullary lesion was noted involving the proximal and mid shaft of the left femur, measuring 18 cm in length and 1.8 cm in width. Thin internal septae with endosteal scalloping along the length of the lesion was seen. The lesion appeared hyperintense on T1WI Fat Sat and STIR sequences were consistent with blood degradation products. Intermediate signal within the lesion on T2WI and STIR sequences was noted suggestive of subacute haemorrhage. No cortical break or associated soft tissue component was seen. No periosteal reaction was noted. The muscles of the thigh showed normal signal intensity. Screening of the right thigh also showed a similar-appearing lesion and blood degradation products within. Review of recent X-ray chest coincidentally showed a lytic lesion in both humeri.
Congenital afibrinogenaemia is a rare autosomal recessive disease which is caused by absence of fibrinogen or factor 1 that results in impaired blood coagulation. The normal value of fibrinogen in the blood is 2 to 4 g/l [1]. In congenital afibrinogenaemia the fibrinogen level is less than 0.2 g/l. There is no predisposition to any gender and males and females are equally affected. The estimated prevalence of this disorder is 1 in a million [2]. This disease is often diagnosed in the neonatal period with 85% presenting with umbilical cord bleeding [3] or bleeding into the gastrointestinal tract, genitourinary tract or into the skin or central nervous system. Musculoskeletal bleeding, including haemarthroses may also occur. Unusual manifestations of afibrinogenaemia include spontaneous rupture of the spleen and presence of bone cysts [4]. Bone cysts, which are one of the rarest complication of afibrinogenaemia, are caused by intraosseous haemorrhage, particularly at the entrance of the nutrient artery [5]. They commonly appear in the contiguity of the cortex or trabeculae in the diaphysis of long bones. Femora, tibiae and humeri are the commonest sites. MRI shows multicystic lesions with septa formation involving meta-diaphyseal junction of the long bones. Intraosseous haemorrhage is better diagnosed on MRI. Whole body MRI screening may be useful to evaluate lesions in other regions. X-ray shows lytic lucent lesions in the diaphysis of long bones. Large bone cysts may cause trabeculae remodelling which may result in pathological fractures in the weight-bearing bones. Furthermore haemorrhage occurs in the bone cysts which causes pain and may be the presenting symptom.
Bone cyst with haemorrhage, as a complication of afibrinogenaemia.
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Based on the provided MRI images and the patient’s symptoms in the left femoral region, a round or oval cystic lesion is observed in the proximal to middle segment of the femoral shaft, showing a multi-loculated or cystic appearance with relatively clear boundaries. The lesion signal may appear as high or mixed intensity on different weighted sequences, indicating the presence of fluid or old hemorrhagic components. No significant swelling or abnormal signal is observed in the surrounding soft tissue. Currently, there is no definite sign of pathological fracture, but given the large cystic change in a weight-bearing bone, one must be vigilant about the risk of pathological fracture.
Considering the patient’s age, history of congenital afibrinogenemia (afibrinogenaemia), imaging characteristics, and clinical symptoms, the most likely diagnosis is:
“Hemorrhagic bone cyst associated with congenital afibrinogenemia/hypofibrinogenemia.”
If uncertainty persists, further imaging follow-up or biopsy (if necessary) could be performed to clarify the nature of the lesion and to assess the risk of pathological fracture.
The rehabilitation focus for this patient is to minimize weight-bearing stress, prevent pathological fractures, and maintain normal muscle strength and joint mobility. Given the presence of an intraosseous cystic lesion and bleeding risk, an individualized and progressive exercise program is advised:
Collaboration with hematology and orthopedics is essential throughout rehabilitation to monitor coagulation function and minimize bleeding risk.
This report is for reference only based on the limited information available and does not replace a professional physician’s in-person consultation or other specialist opinions. The final diagnosis and treatment plan should be made by qualified physicians, taking into account the patient’s actual condition.
Bone cyst with haemorrhage, as a complication of afibrinogenaemia.
