A haemophilic pseudotumour was identified in the mandible of a 5-year-old male with severe haemophilia A. The patient initially experienced painless swelling of the mandible. Computed tomography revealed a marked enlargement of the lower right mandibular border, which was associated with a low-density area, and irregular absorption of the lingual cortex bone. A malignant tumour was suspected, and a biopsy was performed after the administration of coagulation factor (Factor VII). A histopathologic diagnosis of haemophilic pseudotumour was made and the patient subsequently underwent surgical treatment. A cavity was created in the multilocular bone cyst and surgical curettage and irrigation were performed with the same haemorrhagic control as in the biopsy procedure. The multilocular cyst was contained within a haematoma and was surrounded by thin granular tissue. Three years after surgery, no abnormal signs have been detected by radiography during follow-up examinations. This case involved a rare haemophilic pseudotumour located in the mandible; the pathogenetic mechanism was attributed to pressure necrosis due to intraosseous bleeding.
Haemophilic pseudotumour of the bone, which was first reported by Starker in 1918 , is a rare lesion that occurs in patients with severe haemophilia. The true incidence of this complication is difficult to establish, but it has been estimated that 1 or 2% of patients with severe haemophilia develop this condition . A haemophilic pseudotumour, also known as a haemophilic bone cyst, is an extra-articular destructive osseous lesion that causes necrosis of the bone due to pressure from a haematoma . The lesion most frequently occurs in the femur, although it can develop in the pelvis, tibia, and bones of the feet, hands, or wrists. Only 17 cases have been reported in the mandible and three in the maxilla . The first reported case in the mandible was published in 1968 . If the tumour is left untreated, the lesion can cause extensive destruction of the bone and surrounding tissues. The authors present a case of haemophilic pseudotumour in the mandible of a 5-year-old male with a history of haemophilia A. The pseudotumour was unrelated to traumatic injury.
A 5-year-old haemophilic male was referred with painless swelling on the right side of the lower border of the mandible. This swelling had developed 3 months prior to admission. He had not experienced any earlier traumatic injury to his mandible. His parents noted tumour growth up to 30 mm in diameter. The patient’s family history included four haemophiliac brothers and four carrier sisters.
Routine laboratory analyses revealed: haemoglobin level 11.7 g/dl; haematocrit 36.3%; white blood cell count 5800/μl; red blood cell count 4,840,000/μl; platelet count 292,000/μl; prothrombin time 13.0 s; activated partial thromboplastin time 108.2 s; activated factor VIII <1% (severe condition); and factor VIII inhibitor 20 Bethesda units (high inhibitory value). The findings of all other laboratory tests were normal.
A physical examination revealed a round, hard tumour about 30 mm in diameter adherent to the bone and located at the right side of the lower border of the mandible ( Fig. 1 A) . The patient had facial asymmetry caused by the painless right-sided mandibular mass. He had experienced no trauma in this region, and there was no evidence of any injury to his skin or intraoral mucosa. A computed tomography (CT) scan showed a radiolucent space which appeared to protrude to the lingual side of the right mandibular bone ( Fig. 1 B and C). Magnetic resonance imaging (MRI) demonstrated a cystic lesion on the lingual side of the right mandibular bone ( Fig. 1 D and E). The size of this intraosseous lesion was approximately 24 × 10 mm in diameter. The findings of other specific X-ray examinations were normal for his age. Provisional diagnostic imaging of haemophilic pseudotumour versus ameloblastoma was performed, and a biopsy specimen was obtained via an extraoral approach under general anaesthesia during replacement therapy with coagulation factor. Recombinant blood coagulation factor VII (NovoSeven ® ) was injected. Before surgery, 2.4 mg of factor VII was injected, and these injections were repeated every 2 or 6 h with the same dose for 2 days after completion of the surgical procedures. Microscopic examination of biopsy specimens revealed a fibrous capsule surrounding granular tissue with multi-focal haemorrhagic and haemosiderin deposits ( Fig. 2 A and B ). The lesion was histopathologically diagnosed as a haemophilic pseudotumour.