animals Case Report Ossifying Fibroma in the Nasal Cavity of a 2-Year-Old Horse Bernard Turek 1,* , Kamil Górski 1, Olga Drewnowska 1, Roma Buczkowska 1, Natalia Kozłowska 1,* and Rafał Sapierzy ´nski 2 1 Department of Large Animals Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland; [email protected] (K.G.); [email protected] (O.D.); [email protected] (R.B.) 2 Department of Pathology and Veterinary Diagnostic, Institute of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland; [email protected] * Correspondence: [email protected] (B.T.); [email protected] (N.K.); Tel.: +48-604-247-640 (B.T.) Simple Summary: This article reports on the clinical features, diagnosis, and management of ossi- fying fibroma in the nasal cavity of a 2-year-old horse. Ossifying fibromas (OFs) are rare, benign, fibro-osseous neoplasms that occur more frequently in the rostral mandible of young horses (termed equine juvenile mandibular ossifying fibromas) but rarely in older horses. The occurrence of OF in young animals suggests developmental disorders or trauma as etiological factors. The local recur- rence of OFs is common if they are not completely surgically excised, but metastatic spread is unusual. The presented case remained clinically asymptomatic until the mass obliterated the whole nasal cavity, causing severe breathing difficulties. The exact mass location was revealed using diagnostic images—namely, radiographs and computed tomography (CT) images. A concurrent problem of an underdeveloped and hypoplastic last premolar tooth of the maxilla was diagnosed. Because the mass was well-demarcated, the horse underwent standing surgery to remove the mass and the tooth. Histopathological diagnosis of ossifying fibroma was confirmed. The patient recovered uneventfully Citation: Turek, B.; Górski, K.; and remained free of disease at the 2-year postoperative follow-up. Drewnowska, O.; Buczkowska, R.; Kozłowska, N.; Sapierzy´nski,R. Abstract: A 2-year-old mare of an unknown breed was referred to the clinic due to undetermined Ossifying Fibroma in the Nasal breathing difficulties. Physical examination revealed painless swelling rostral to the nasoincisive Cavity of a 2-Year-Old Horse. Animals notch and a large, firm mass protruding from the left nostril. Radiographic examination of the head 2021, 11, 317. https://doi.org/ revealed a mass occupying the left nasal cavity and a displaced and hypoplastic last premolar of the 10.3390/ani11020317 left maxilla. The CT scan showed a well-demarcated heterogeneous mass measuring 22 × 9 × 5 cm Academic Editor: Alessandro Spadari (length × height × width) in the left nasal cavity attached to the roots of the displaced tooth and Received: 23 November 2020 conchae. The surgery was performed on the standing horse. Firstly, due to the oblique position of the Accepted: 20 January 2021 displaced tooth, the extraction was performed extra-orally through the trephination and repulsion Published: 27 January 2021 of the maxillary bone. In the next step, a direct surgical approach was chosen for the caudal part of the mass via the osteotomy of the left nasal bone. The mass was bluntly separated from the conchae Publisher’s Note: MDPI stays neutral and removed through the nostril using Fergusson forceps. The histopathological characteristics of with regard to jurisdictional claims in the mass led to the diagnosis of ossifying fibroma. The horse recovered completely in seven months, published maps and institutional affil- without recurrence after two years. iations. Keywords: tumor; ossifying fibroma; tooth; extraction; computed tomography Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. 1. Introduction This article is an open access article There are no clear-cut data on the incidence of tumors in the skeletal system in horses. distributed under the terms and Only in one paper was the rate of occurrence reported to be below 1.5% [1]. conditions of the Creative Commons Ossifying fibromas (OFs) are fibro-osseous neoplasms that most commonly occur on Attribution (CC BY) license (https:// the intramembranous bone of the skull and mandible [2] and rarely in the appendicular creativecommons.org/licenses/by/ 4.0/). skeleton [3]. Fibro-osseous lesions have been reported in humans [4,5] and a variety Animals 2021, 11, 317. https://doi.org/10.3390/ani11020317 https://www.mdpi.com/journal/animals Animals 2021, 11, 317 2 of 11 Animals 2021, 11, x 2 of 12 of domestic animals, including dogs [6], cats [7], rabbits [8], llamas [9], birds [10], and ruminantsdomestic [animals,11–13]. including dogs [6], cats [7], rabbits [8], llamas [9], birds [10], and rumi- nantsIn horses,[11–13]. ossifying fibromas usually affect the rostral part of the mandible of young animalsIn agedhorses, between ossifying 2 and fibromas 15 months usually and affect are termedthe rostral equine part juvenileof the mandible mandibular of young os- sifyinganimals fibromas aged between (EJMOFs). 2 and These 15 months lesions and may are replace termed alveolar equine andjuvenile cortical mandibular bone, cause ossi- thefying loosening fibromas of the(EJMOFs). teeth, interfere These lesions with themay mastication replace alveolar of food, and and cortical predispose bone, cause the jaw the toloosening pathological of the fractures teeth, interfere [14]. Although with the the ma causestication of OFof food, is unknown, and predispose several hypothe-the jaw to sespathological have been suggested,fractures [14]. including Although developmental the cause of disorders OF is unknown, that may several affect ossification hypotheses athave a young been agesuggested, as well including as trauma developmental [15]. Other reports disorders have that described may affect OF ossification in horse max- at a illayoung [16], paranasalage as well and as trauma sphenopalatine [15]. Other sinuses reports [17 –have19], proximaldescribed tibia OF in [20 horse], and maxilla the fourth [16], metacarpalparanasal boneand sphenopalatine [21]. sinuses [17–19], proximal tibia [20], and the fourth meta- carpalOssifying bone [21]. fibromas tend to recur if they have not been completely removed, but metastaticOssifying spread fibromas is unusual tend [ 22to ].recur The if objective they have of not the been present completely paper isremoved, to describe but themet- clinical,astatic imaging,spread is andunusual pathological [22]. The findingsobjective of of an the ossifying present paper fibroma is to in describe the nasal the cavity clinical, of aimaging, horse. and pathological findings of an ossifying fibroma in the nasal cavity of a horse. 2.2. Materials Materials and and Methods Methods 2.1.2.1. Case Case Presentation Presentation AA 2-year-old 2-year-old mare mare of of an an unknown unknown breed breed was was admitted admitted to to the the clinic clinic due due to to breathing breathing difficulties. On initial examination, the general conditions of the patient were assessed difficulties. On initial examination, the general conditions of the patient were assessed as as poor because of malnutrition, poor quality of fur, and general neglect. Breathing was poor because of malnutrition, poor quality of fur, and general neglect. Breathing was strid- stridulous, with no passage of air through the left nostril. Temperature and pulse were ulous, with no passage of air through the left nostril. Temperature and pulse were within within normal limits. A deformation was visible on the left side of the head, rostral to the normal limits. A deformation was visible on the left side of the head, rostral to the naso- nasoincisive notch. Epiphora was noted in the left eye. During a detailed examination, a incisive notch. Epiphora was noted in the left eye. During a detailed examination, a firm, firm, non-shifting mass protruding from the left nostril was found (Figure1). non-shifting mass protruding from the left nostril was found (Figure 1). Figure 1. Firm mass protruding from the left nasal cavity of a mare with breathing difficulties. Figure 1. Firm mass protruding from the left nasal cavity of a mare with breathing difficulties. 2.2.2.2. X-ray, X-ray, CT, CT, Endoscopy Endoscopy Examination Examination RadiographsRadiographs were were obtained obtained byby computedcomputed radiography (Gierth HF HF 80 80 Plus, Plus, Gierth Gierth X- X-rayray International, International, Germany, Germany, and ConsoleConsole AdvanceAdvance DR-IDDR-ID 300300 CL, CL, Fujifilm Fujifilm Corporation, Corporation, Tokyo,Japan) Japan) with an with indirect an indirect conversion conversion system system for scanning. for scanning. The leftThe latero-lateral left latero-lateral (LL) and (LL)right and 30° right dorsal–left 30◦ dorsal–left ventral oblique ventral oblique(Rt30D-LeVO) (Rt30D-LeVO) projections projections were assessed. were assessed. A well-de- A well-delineated,lineated, oval-shaped, oval-shaped, and slightly and slightly heterogeneous heterogeneous mineral mineral opacity opacity was seen was within seen within the left thenasal left nasalpassage, passage, extending extending from fromthe level the level of 208 of 208to the to thenostril nostril (Figure (Figure 2a)2 a)[23]. [ 23 Triadan]. Triadan 208 208was was displaced displaced into into the the rostral rostral aspect aspect of the of the nasal nasal cavity. cavity. The The morphology morphology of tooth of tooth 208 208 was wasabnormal, abnormal, with with markedly markedly