Histopathological analysis of biopsies of "peri-implant inflammatory lesions." Everything is not what it seems

Peri-implantitis is the inflammatory process, which most commonly affects the therapy with dental implants. However, there are other reactive and neoplastic entities, mainly benign but also malignant, which also take place in the peri-implant mucosa. There is little information about the histopathological analysis of these peri-implant inflammatory diseases.

To analyze the histopathological diagnosis of biopsies located in the peri-implant mucosa that showed an inflammatory clinical appearance.

We have made a retrospective study of 111 peri-implant biopsies analyzed in the Oral and Maxillofacial Pathology Unit of the Dental Clinic Service at the University of the Basque Country, from January 2001 to December 2018. These samples corresponded to 84 women and 27 men, whose mean age was 59 years. We performed a standard histological processing with paraffin embedding, and sections were stained with H&E and PAS. All cases were analyzed following a specific diagnostic histopathological protocol. A descriptive statistical analysis was carried out with the obtained data.

Lesions located in the mandible (64.8%) were more frequent and 34.2% of the biopsies arrived without a presumptive clinical diagnosis. "Inflammatory peri-implant lesion" or peri-implantitis was the most common clinical diagnosis. Histopathologically, the majority of the lesions were peri-implant nonspecific inflammatory hyperplasia (60.3%), followed by peripheral giant cell granuloma (18.1%), pyogenic granuloma (lobular capillary hemangioma) (14.4%), actinomicotic infection (3.6%), and squamous cell carcinoma (3.6%). Individually, peri-implant lesions were more common among women and in the mandible, except for actinomicotic infection and squamous cell carcinoma.

An important percentage of cases whose initial presumptive clinical diagnosis was "peri-implant inflammatory lesion" truly corresponded to other reactive and neoplastic processes. Thus, it is key to always submit all the tissue removed during the implant surgery, in order to perform a good histopathological study and achieve the correct final diagnosis.