Periocular sarcoid in a horse

A case of lipogranulomatous conjunctivitis in a horse

OBJECTIVE

To describe a case of lipogranulomatous conjunctivitis in a horse.

ANIMAL STUDIED

A client-owned 12-year-old Standardbred gelding presenting with chronic conjunctivitis and palpebral masses.

METHODS

Complete ophthalmic examination, surgical excision, histopathology, and bacterial culture of biopsy samples were performed.

RESULTS

Upper and lower eyelids of both eyes were affected, with multiple yellow-to-white nodules on the palpebral conjunctiva, adjacent to the eyelid margin. Nodule removal was achieved via partial tarsal plate excision. Histopathological examination revealed granulomatous inflammation and large droplets of presumed free lipid in the conjunctival lamina propria. The animal was diagnosed with lipogranulomatous conjunctivitis. No postoperative ocular discomfort was observed for months; however, 3 years later, new conjunctival nodules were noticed, requiring a second surgical procedure on three of the eyelids. Transient entropion in the left lower eyelid was observed 2 months after the second surgery, and no recurrence of conjunctival nodules was observed after 18 months of follow-up.

CONCLUSION

To our knowledge, this is the first report of lipogranulomatous conjunctivitis in horses.

Anatomical, Histological and Histochemical Observations of the Eyelids and Orbital Glands in the Lowland Tapir (Tapirus terrestris Linnaeus, 1785) (Perissodactyla: Ceratomorpha)

The lowland tapir is one of four species belonging to the Tapiridae family of the Ceratomorpha suborder, similar to Rhinocerotidae. This study describes anatomy with morphometry, histology (hematoxylin and eosin, Masson-Goldner trichrome, Movat pentachrome, mucicarmine, picro-Mallory trichrome) and histochemistry (PAS, AB pH 1.0, AB pH 2.5; AB pH2.5/PAS and HDI) of the upper and lower eyelids, and superficial gland of the third eyelid with the third eyelid, deep gland of the third eyelid, and lacrimal gland. The aim of the work is to show the features of the above-mentioned structures typical only for Tapiridae, as well as to show the presence of similarities and differences between the families forming the order Perissodactyla. The eyelashes on the upper eyelid were long, while those of the lower eyelid were short and much less prominent. In the upper and lower eyelid sebaceous glands, a characteristic simple alveolar gland producing a mucus-like secretion and poorly developed tarsal glands were observed. The marginal zone of the posterior surface of the eyelids was covered by stratified columnar epithelium with 18-21 layers of nucleated cells, while the bulbar zone of these surfaces was covered by cubic multilayer epithelium with 6-11 non-keratinized layers of cells and with sparse goblet cells. In only lower eyelids, numerous lymphoid nodules, diffuse lymphocytes and high endothelial venules were observed. The superficial gland was an acinar complex which secreted mucous and contained plasma cells within the interlobular and interlobular connective tissue. The upper and lower branches of the third eyelid were the shape of a bent "caudal fin" and were composed of hyaline cartilage, and they contained conjunctiva associated lymphoid tissue (CALT). The deep gland was also an acinar complex producing a serous character and having numerous diffuse lymphocytes. The lacrimal gland was an acinar complex producing seromucous secretions and had numerous plasma cells located in the glandular interstitium. The results of our research indicate that the features of the anatomy of the eyelids and orbital region in the lowland tapir are also typical of the family Tapiridae, but also have features common to the families Equidae and Rhinocerotidae. We confirm the presence of poorly developed tarsal glands in both eyelids as well as presence of a palpebral part of the lacrimal gland in the upper eyelid, which is typical only to Tapirus terrestris.

Immunotherapy of Equine Sarcoids—From Early Approaches to Innovative Vaccines

Horses and other equid species are frequently affected by bovine papillomavirus type 1 and/or 2 (BPV1, BPV2)-induced skin tumors termed sarcoids. Although sarcoids do not metastasize, they constitute a serious health problem due to their BPV1/2-mediated resistance to treatment and propensity to recrudesce in a more severe, multiple form following accidental or iatrogenic trauma. This review provides an overview on BPV1/2 infection and associated immune escape in the equid host and presents early and recent immunotherapeutic approaches in sarcoid management.

Repurposing Infectious Diseases Vaccines Against Cancer

Vaccines used to prevent infections have long been known to stimulate immune responses to cancer as illustrated by the approval of the Bacillus Calmette-Guérin (BCG) vaccine to treat bladder cancer since the 1970s. The recent approval of immunotherapies has rejuvenated this research area with reports of anti-tumor responses with existing infectious diseases vaccines used as such, either alone or in combination with immune checkpoint inhibitors. Here, we have reviewed and summarized research activities using approved vaccines to treat cancer. Data supporting a cancer therapeutic use was found for 16 vaccines. For 10 (BCG, diphtheria, tetanus, human papillomavirus, influenza, measles, pneumococcus, smallpox, typhoid and varicella-zoster), clinical trials have been conducted or are ongoing. Within the remaining 6, preclinical evidence supports further evaluation of the rotavirus, yellow fever and pertussis vaccine in carefully designed clinical trials. The mechanistic evidence for the cholera vaccine, combined with the observational data in colorectal cancer, is also supportive of clinical translation. There is limited data for the hepatitis B and mumps vaccine (without measles vaccine). Four findings are worth highlighting: the superiority of intravesical typhoid vaccine instillations over BCG in a preclinical bladder cancer model, which is now the subject of a phase I trial; the perioperative use of the influenza vaccine to limit and prevent the natural killer cell dysfunction induced by cancer surgery; objective responses following intratumoral injections of measles vaccine in cutaneous T-cell lymphoma; objective responses induced by human papillomavirus vaccine in cutaneous squamous cell carcinoma. All vaccines are intended to induce or improve an anti-tumor (immune) response. In addition to the biological and immunological mechanisms that vary between vaccines, the mode of administration and sequence with other (immuno-)therapies warrant more attention in future research.