The Diagnostic Role of the Marginal Vacuoles in FNAC of Solitary Thyroid Nodules

Abstract

Context: FNAC thyroid is more sensitive as well as specific in segregating neoplastic and non-neoplastic thyroid lesions. Identification of predominant cell pattern, cell morphology and background details in FNAC smears play an important role in categorisation of various thyroid lesions with accuracy. Marginal vacuoles (MVs) have been described as irregular cytoplasmic vacuoles with largely unstained central area. MVs, although suggestive of thyrotoxicosis, are non-specific, as they are also encountered in non-toxic goitre, Hashimoto's thyroiditis and follicular carcinoma. This cytologic finding therefore deserves further study to precisely delineate its utility. Methods & Material:Forty patients having solitary thyroid nodule were subjected to FNAC on an outpatient basis. Their cytomorphological features were studied with special attention to presence of MVs. MVs if present were then graded as no/ scant (gradeI ), moderate (gradeII) and abundant (gradeIII).Results and Conclusion: Majority (77.5%) of nodular goitres had insignificant MVs (gradeI) in their smears. Significant MVs (gradeII+III) were limited to autoimmune thyroiditis presenting as solitary nodule and follicular neoplasms. Abundant MVs/ gradeIII were seen in follicular neoplasm only. MVs were not present in rest of neoplastic goitres. This implies that MVs are a marker of follicular differentiation.