A healthy 24-year-old woman presented with gingival bleeding in the right upper right posterior teeth during the last 6 months. The patient also reported episodes of mild pain and a gradual deviation of the teeth. There were no signs of fever or pus.
A general systemic examination of the patient revealed no abnormalities. Local examination revealed a diffuse swelling of 1 x 3 cm in the alveolus corresponding to the upper right molars. The swelling was more prominent on the vestibular side. The surface appeared rough and erythematous. There were no visible pulsations in the lesion. The aforementioned teeth were deviated towards the palate. On palpation, the swelling showed a hard consistency. The three affected teeth did not respond to heat, cold or electrical pulp stimulation. Orthopantomography was inconclusive. A contrast-enhanced computed tomography (CT) scan showed a soft tissue mass in the right maxillary alveolus, without bone erosion. Radiological examinations and routine haematological examinations, including coagulation tests, revealed no abnormalities.

Based on clinical, radiological and CT findings, a provisional diagnosis of giant cell lesion was made, and an incisional biopsy of the vestibular gingiva was performed. Marginally increased intraoperative bleeding was evident, but was attributed to inflammation.
The pathology report of the specimen revealed fibrovascular connective tissue with aggregates of numerous dilated endothelial capillaries and venules suggestive of AVM. After consultation with an interventional radiologist, resection of the lesion was decided and performed under general anaesthesia. The single specimen included vestibular and palatal gingivae, alveoli, and the affected teeth. Haemostasis was achieved and the defect was closed by first intention by advancement of the palate and buccal mucosa. The perioperative period and recovery was uneventful and comfortable for the patient.
Pathological analysis of the specimen was very similar to that of the incisional biopsy and revealed numerous arterioles and venules interspersed between the bony trabeculae, extending into the gingiva suggesting arterio-venous malformation.

The patient was followed up for a period of 1 year without recurrence.