parathyroid cytology: a diagnostic dilemma

INTRODUCTION Neck nodules are common in clinical practice which are accessible to Fine needle aspiration cytology (FNAC). Thyroid being the commonest organ to present as the nodular lesions. Parathyroid lesions can be incidentally encountered during FNA of a thyroid nodule Fine needle aspiration cytology is a safe economical and leading investigation in the diagnosis of neck nodules. Thyroid and parathyroid nodules are indistinguishable clinically. An attempt is made to familiarise the pathologist about the cytomorphological features of parathyroid nodules and simple approach to differentiate from thyroid nodules. MATERIALS AND METHODS It is a retrospective study conducted over a period of 5 years from 2011-2016. Twelve cases of histologically proven parathyroidal lesions are the subjects of study of which 4 cases were diagnosed as parathyroidal cyst and rest as parathyroid adenoma. All the cases underwent fine needle aspiration cytology under ultrasound guidance, Smears were made, stained by H & E and PAP staining method, the slides were reviewed by two cytopathologists. Biochemical and radiological findings were evaluated before giving definitive cytological diagnosis. RESULTS A total number of 12 cases which were histologically proven as parathyroidal lesion. Out of which 4 were cystic lesions which were excluded from the study. Rest of the 8 cases confirmed as parathyroid adenoma which had FNAC were evaluated. 5 cases had positive cytohistological correlation. Three out of 8 cases were diagnosed as papillary carcinoma of thyroid, Toxic nodular goitre and Hurthle cell neoplasm due to varied cytomorphology. CONCLUSION Parathyroidal lesions has got low sensitivity and specificity in cytology. The confident diagnosis of parathyroid neoplasm was made in conjunction with biochemical and advanced radiological imaging. In neck nodules which are asymptomatic and at abnormal locations, FNAC through its cytomorphological features has an edge in diagnosis.