Case ReportGigantic Ocular Squamous Cell Carcinoma Mixed With Fibrosarcoma in a Mare: Clinical, Laboratory, Ultrasonography and Histopathology Findings
Introduction
Ocular neoplasms represent about 10% of all neoplasms in horses and ocular squamous cell carcinoma (OSCC) is the most commonly recorded one [1]. Equine ocular neoplasia constitutes diagnostic and therapeutic challenges. The diagnostic challenge arises from the difficulty of collection of tissue samples for cytology and histopathology before surgery while the therapeutic challenge arises from the malignancy of the majority of equine ocular neoplasms. Therefore, an adjunctive treatment such as immunotherapy and chemotherapy after surgical excision is mandatory in most cases [2].
The OSCC is a malignant neoplasm of the eye and ocular adnexa [3,4]. It affects the cornea, limbus, conjunctiva and eyelids in horses [5], [6], [7], [8], [9].
Although the etiology of OSCC has not been fully documented [4], there are several suggested causes such as; prolonged sunlight exposure, Papillomavirus, and changes in estrogen as well as androgen levels [10], [11], [12], [13]. OSCC usually affects middle-aged to older horses that belong to the breeds with a grey hair coat [4,11,14].
There are several diagnostic modalities for OSCC in equine such as clinical signs, ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI) and histopathology [15].
Although OSCC has a low distant metastatic rate of 18% [16], it has characters of malignancy, like local invasiveness to the iris, sclera and extra-ocular tissues (orbit, nasal cavity and sinuses), and recurrences [9,17,18]. The reported recurrence rate is 11.1-66.7% and depends upon the therapeutic technique and origin of neoplasm, corneal SCC has a lower recurrence rate than the SCC of eyelids [11,14,16].
Several treatments have been applied for OSCC such as; surgical excision, immunotherapy, intralesional chemotherapy with cisplatin, and surgical excision with adjunctive therapy like cryotherapy, radiofrequency hyperthermy, chemotherapy, radiation therapy, CO2 laser ablation and photodynamic therapy [1,11].
Despite numerous publications on deep neoplasia of the cornea, no tumor penetrating the Descemet's membrane has yet been described [5,8,19]. It seems that this membrane is resistant to the invasion of neoplastic cells, which spread around its borders.
Although OSCC is commonly reported in horses, ocular fibrosarcoma is a rare neoplasm. To the authors, knowledge, a mixed neoplasm of OSCC and fibrosarcoma has not been recorded before in equine practice. Therefore, this case report adds to the veterinary literature the clinical, laboratory, ultrasonography, postmortem, histopathology and immunohistochemistry findings in a 10-year-old draft mare with unusual gigantic OSCC mixed with fibrosarcoma and associated with cartilaginous and osseous metaplasia.
Section snippets
Case Description
A 10-year-old draft mare was admitted to the surgery clinic at Faculty of Veterinary Medicine, Cairo University for examination of a left ocular mass.
The owner had noticed a mass at the left eye (OS) with excessive lacrimation, blepharospasm and eye discomfort one year prior to referral. No history of trauma or other diseases was mentioned by the owner. The mare was located at a rural area with lack of veterinary service. The owner gave the mare topical anti-inflammatory and antibiotic eye
Discussion
This report records a very rare unilateral mixed neoplasm of OSCC and fibroarcoma that has not been reported previously in horses. The recorded neoplasm here was associated with cartilaginous and osseous metaplasia and destructed the left eye completely.
An ocular neoplasm was strongly suspected depending upon the ophthalmic and ultrasound examinations however, histopathology and immunohistochemistry were essential to confirm the final diagnosis. Based upon the neoplastic spindle‐shaped cells,
Conclusion
Despite the unsuccessful outcome in this particular case, this report documents a mixed eye neoplasm, highlights the ultrasonography and histopathology features of OSCC, and reinforces the need for early diagnosis and surgical treatment in such cases to decrease the drastic complications and mortality.
Acknowledgments
None
Financial Disclosure
This research didn't receive any specific grant from funding agencies from any sector.
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Conflict of Interest: All authors declare no conflict of interest concerning the publication of this case report. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Ethical statement: All international and institutional guidelines for animal use and care were followed up. All authors approved the writing and submission of this manuscript and none of them has any conflict of interests. This case report was not published elsewhere before in any form.