Mixed thymic tumor in a rooster: gross and histological features

Abstract

A 2-year-old rooster local breed suffered from anorexia, emaciation with an abnormal large mass in the lateral side in the cervical region was attended to Veterinary Teaching Hospital belong to College of Veterinary Medicine, Mosul University. After physical examination a movable and friable mass was recognized in the cervical region, the case sends for surgical intervention. Gross examination of the removed mass showed a friable, pale, will capsulated with hemorrhagic areas. Microscopically, the mass included three types of tumors. Squamous cell thymic carcinoma characterized by the presence of keratin pearl. Lymphoma that characterized by atypical polymorphic lymphocytes, vesicular nucleus, and pyknotic nucleoli, while cytoplasm appears eosinophilic to granular with ill-define borders. Lipoma which appears as irregular shape of adipocytes that lack their nucleus, with scattered infiltration of pyknotic lymphocytes. This is the first pathological report of mixed tumor of the thymus gland in rooster that composed from squamous cell thymic carcinoma, lymphoma and lipoma.

Pathological study of neoplasms surgically excised from animals attended the veterinary teaching hospital

“…A case of the mixed thymic tumor was designated in a rooster of a local breed that composed from squamous cell carcinomas due to presence of keratin pearls and welldifferentiated thymoma and lipoma (5).…”

“…Thymoma also a popular type of tumor in chickens especially that affect with lymph proliferative viruses as in case of Marek's diseases in chickens, this tumor composed from atypical polymorphic T lymphocytes with ill-defined borders and they characterized by large size with a nucleus in spindle shape (5).…”

“…Surgical pathology of tumours in animals is widely described around the world in both farm and pet animals, with more advanced studies in the prevalence of each tumour type and their grading with prognosis (1). In Iraq, few studies are conducted to explain types of tumours in different species of animals, most of them are present to the scientific community as case reports, which emphasizing on describing these cases from a clinical perspective, only a few of them were conducting a pathological study to clear their histopathological architecture of neoplastic cells (2)(3)(4)(5). In Iraq, especially in pet animals, the prevalence of this condition is obscure, and they were recorded as a case report only, without advanced study to causes and pathology of them (6).…”

“…In Iraq, especially in pet animals, the prevalence of this condition is obscure, and they were recorded as a case report only, without advanced study to causes and pathology of them (6). The most common types of tumour that have been recorded in Iraq are cutaneous papilloma, cutaneous fibroma, hepatic adenoma, cutaneous squamous cell carcinoma, lipoma, and thymoma (2)(3)(4)(5). Few of previous studies explained the histological nature of these types of tumours; others were describing the gross lesions with emphasizing on the clinical aspects of these cases (7).…”

“…Few of previous studies explained the histological nature of these types of tumours; others were describing the gross lesions with emphasizing on the clinical aspects of these cases (7). In Mosul city, the neoplastic masses which have been recorded are bovine cutaneous papilloma, cutaneous squamous cell carcinoma, and mixed thymic tumour (2,3,5). This study aimed to investigate the pathology of surgically excised tumours in animals that attended Veterinary Teaching Hospital (VTH), College of Veterinary Medicine, University of Mosul.…”