Oral neurovascular hamartoma: a lesion searching for a name

Neurovascular hamartoma (NVH), in particular in the oral cavity, is rarely described in the literature. The low number of cases may reflect a genuine rarity of the lesion, or it may be due to its being unrecognized and/or under-reported.

To investigate clinical and microscopic features of oral NVH and to define microscopic diagnostic criteria with emphasis on the differential diagnosis.

Archival cases diagnosed as oral NVH between 1999 and 2011 were retrieved; clinical and demographic data were collected, and a paired morphometric analysis was conducted, with each case of NVH a case of fibrous hyperplasia (FH) from the same oral location. The nerve bundle and blood vessel density were quantified in five microscopic fields at ×100 magnification.

The study group included 25 oral NVH, 11 men and 14 women, aged 6-76 years, (mean 44). The majority occurred in the tongue (54%), followed by the buccal mucosa and lower lip (17% each), clinically presenting as asymptomatic 0.25-2.5 cm exophytic masses. Microscopic characteristics included poorly circumscribed masses of closely packed nerve bundles and blood vessels in a loose matrix, containing minimal or no inflammation. The mean nerve bundle density was significantly higher in NVH (4.28 ± 1.26) in comparison with FH (0.27 ± 0.27), (P < 0.00001), and mean vessel density was significantly lower (5.98 ± 1.4 vs. 7.8 ± 1.9, respectively), (P < 0.0003).

Oral NVH may not be as rare as previously considered. Morphometric analysis demonstrated that NVH presents a separate distinct entity.