Nasal tissue-derived hamartoma in the maxillary gingiva of a calf.

BACKGROUND: All of oral hamartomas has been previously found in mandibular gingiva in younger calves, and were histologically diagnosed as a vascular hamartoma. This is the first case report describing a calf with a mass in the maxillary gingiva that was histologically diagnosed as a nasal tissue-derived hamartoma. CASE PRESENTATION: A 13-day-old male Holstein calf presented with a horn-like mass in the left rostral maxillary gingiva. Surgical removal revealed that the mass had a dual structure composed of cartilaginous and soft tissues and extended deeply toward the nasal cavity. Excised tissues mainly consisted of two types of mature cells without mitotic figures and atypia: 1) the cartilage-like structures consisted of an island and a meandering massive focus of mature cartilaginous tissues, and 2) tubular structures consisting of stratified ciliated mucosal columnar cells with gland-like structures and aggregated goblet cells. The mass was diagnosed as a nasal tissue-derived hamartoma because these two types of structures were histologically identical to nasal structures. The present case had no recurrence at 1 year after surgery. CONCLUSIONS: To our knowledge, this is the first description of the calf with nasal tissue-derived hamartoma in the maxillary gingiva.