Rostral hard palate swelling (lampas) in horses: true or fiction?

Overview

• This study investigated the presence and nature of swellings called lampas on the front part of the hard palate in horses of various ages.
• It aimed to determine how common these swellings are and to analyze their tissue characteristics to understand whether they are pathological or normal variations.

Study Objectives and Design

• The main goal was to assess how often rostral hard palate swellings (lampas) occur in horses across different age groups: young, adult, and elderly.
• The study also sought to perform histological (microscopic) analysis to characterize these swellings and distinguish them from inflammatory or pathological lesions.
• 120 horses were orally inspected, and those with visible lampas were identified based on mucosal extension beyond the occlusal surface of the upper incisors.
• Samples of palatal mucosa were collected from affected horses for laboratory study.
• For comparison, 10 horses without hard palate alterations (euthanized due to unrelated reasons) were included as a control group.

Key Findings

• Approximately 23% of the evaluated horses (28 out of 120) showed the presence of swellings on the rostral hard palate.
• Histological examination revealed mucosal hyperplasia (an increase in the number of cells causing tissue enlargement) in only one case.
• No samples exhibited signs of inflammation, which would typically indicate infection or disease.
• Measurements of tissue layers such as lamina propria and keratinized epithelium showed no significant differences between age groups with the swelling and control horses (statistical significance p > 0.05).

Interpretation and Clinical Implications

• The absence of inflammation and minimal histological changes suggest that lampas may often be normal anatomical variations or an adaptive response rather than a pathological condition.
• Clinical misinterpretation of lampas as a disease could lead to unnecessary surgical interventions.
• In some cases, surgical removal of lampas might temporarily improve stereotypic behaviors, but such improvement does not reflect a true resolution of an underlying disease.
• Based on the findings, routine surgical excision of these swellings is rarely justified because they do not indicate a health problem requiring treatment.

Conclusion

• The study highlights that rostral hard palate swellings (lampas) in horses are relatively common and likely benign.
• Veterinarians should recognize these swellings as potential normal variations to avoid unnecessary procedures.
• Further research might focus on understanding any functional adaptations associated with these swellings and their relation, if any, to equine behavioral conditions.