Histological pattern of thyroid gland neoplasms in Kano, Northern Nigeria

Thyroid gland neoplasms occur globally with geographical variation in incidence and histopathological pattern related to age, sex, dietary and environmental factors. There is, however, no published histological study from northwestern Nigeria; hence, the need for this retrospective study to document the pattern in Kano.

This was a retrospective study of all histologically diagnosed thyroid neoplasms in the Department of Pathology, Aminu Kano Teaching Hospital (AKTH), Kano Nigeria, over a ten year period from 1st January, 2002 to 31st December, 2011.

A total of 522 thyroid specimens (1.5% of all biopsies) were received over the ten year period. Thyroid neoplasms accounted for 157 (30.1%) of all the thyroid specimens, comprising 130 females (82.8%) and 27 males (17.2%) with female to male ratio of 4.8:1. The ages range from 15 to 80 years with a mean age of 35.8 years and peak occurrence in the 4th decade. There were 82 cases (52.2%) of thyroid adenoma (mostly follicular) while thyroid carcinoma accounted for 66 cases (42%). Papillary carcinoma predominated (53%) followed by follicular carcinoma (33.3%) and medullary carcinoma (9.1%). One case each (1.5%) of anaplastic carcinoma, squamous cell carcinoma and metastatic squamous cell carcinoma were seen. All the malignant tumours were epithelial and all except one were primary thyroid malignancy.

Thyroid neoplasmis a common thyroid gland lesion in Kano with a striking female preponderance. Thyroid adenoma was the most common benign neoplasm while papillary carcinoma seen a decade earlier in females was the most common malignant thyroid neoplasm. The predominance of papillary carcinoma over follicular carcinoma is a reverse of the finding of an earlier clinicopatholgical study on thyroid gland diseases in Kano.