In January 2016, a 20-year-old female oriental small-clawed otter (Aonyx cinereus) from Night Safari in Singapore was euthanized and diagnosed with a thyroid gland carcinoma. Postmortem examination and histology also revealed metastasis to the regional lymph nodes and severe visceral pentastomiasis. Grossly, the lymph nodes were infested, and encapsulation was observed on the visceral serosal surface. Histopathologically, the lymph nodes were encysted by a thick fibrous connective capsule with minimal inflammatory response. Pentastomiasis has been previously reported in the smooth-coated otter (Lutrogale perspicillata) in Malaysia. This report is the first case of severe visceral pentastomiasis in an oriental small-clawed otter with functional thyroid carcinoma.
There has been a growing awareness of the association between papillary thyroid carcinoma and familial adenomatous polyposis (FAP). The cases of four young patients with papillary thyroid carcinoma occurring with FAP are presented. Three patients underwent surgery to provide specimens for detailed histological examination. The surgical specimens showed well-encapsulated multicentric tumours exhibiting a predominantly papillary architectural growth pattern. In some areas, follicular architecture and cribriform patterns were noted. Atypical areas of spindle cells in a trabecular or solid configuration, which are not normally seen in classical papillary thyroid carcinoma, were evident. Malignant cells exhibited a graduation of cuboidal to tall cells with abundant amphophilic cytoplasm. The nuclei did not exhibit the typical nuclear clearing as seen in papillary thyroid carcinoma, but nuclear grooving and inclusions were noted. Psammoma bodies were not seen in any of the specimens. In a limited review of these patients, features such as young age at presentation, multicentricity and unusual histology suggest that thyroid carcinoma associated with FAP may represent a distinct form of thyroid cancer.
Thyroid cancer is the most common among all endocrine malignancies. The worldwide prevalence of goitre in the general population is estimated at 4-7 percent and the incidence of malignancy in goitrous thyroid is about ten percent. It is postulated that goitrous thyroid is a precursor lesion to the development of malignant thyroid diseases. As Sarawak is a state well known for endemic goitre, this study focused on establishing the incidence of thyroid malignancy among goitrous thyroid swellings.