Varied histopathological changes in thyroid lumps mimicking carcinoma radiologically: a Diagnostic Dilemma

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Varied histopathological changes in thyroid lumps mimicking carcinoma radiologically: a Diagnostic Dilemma

Journal Title: International Journal of Medical Science and Innovative Research (IJMSIR) - Year 2018, Vol 3, Issue 1

Abstract

Fine needle aspiration cytology (FNAC) of the thyroid gland is a first-line diagnostic test for evaluation of diffuse thyroid lesions as well as of thyroid nodules with the main aim of differentiating benign from malignant lesions and reducing unnecessary surgery [Orell SR, et al.,2005]. One of the common modalities in determining the diagnosis of thyroid lesions is fine needle aspiration. It is minimally invasive and cheap with good patient compliance and gives around 80 to 90% diagnostic yield.[4] However there are diagnostic difficulties in a post FNAC thyroidectomy specimen. TB in India is extremely common especially in young, adults than other age group. It is more common in female population in India where women remain poor and neglected.[1] Tuberculosis [TB] burden continues to remain huge with more than half cases not getting registered under Revised National Tuberculosis Programme [RNTCP].Tuberculosis commonly is pulmonary where it exists as primary ,primary progressive, secondary and disseminated. Common extrapulmonary TB sites are the intestine skin, liver spleen meninges etc. In meninges tuberculosis commonly occur as abscess. When those abscesses rupture and release bacteria, tuberculosis meningitis occurs.[2] Thyroid is one of the lesser known organs to be affected by tuberculosis. The thyroid gland maybe involved in two forms , first, and the more common, is miliary spread to the thyroid gland as a part of generalized dissemination. Second is the focal caseous tuberculosis of thyroid presenting as a localized swelling mimicking a tumor , a cold abscess, or a multinodular goiter with rarely an acute abscess.[3] Thyroid undergoes secondary changes due to introduction of the needle. These changes can be schematically divided into two major groups--recent ones (intranodal bleeding and/or necrosis) and subacute/late ones (proliferation of granulation tissue with predominance of myofibroblasts or endothelial cells, resorptive pseudoxantomathous granulomas, formation of sarcoid-like granulomas, capsular pseudoinvasion and scarring).[5]These varied histological alteration also called as Worrisome histological alterations following fine needle aspiration (WHAFFT) are seen in thyroid tissue due to trauma caused by the aspiration needle in FNAC. These include acute changes such as hemorrhage, granulation tissue, mitosis, granuloma, capsular distortion (pseudoinvasion) and infarction, and chronic alterations such as fibrosis, metaplasias, infarction, cholesterol granuloma, cyst formation, degeneration, papillary endothelial proliferation and calcification [LiVolsi VA et al;1994]. They cause difficulty in diagnosis of histopathological specimen received thereafter. Squamous epithelium in thyroid lesions is an unusual finding and their presence has been attributed to metaplastic change in follicular epithelium by some authors or persistence of ultimo-bronchial body by others in areas of fibrosis and inflammation, secondary to hemorrhage. If it is extensive with associated degenerative epithelial changes, it can be easily confused with primary or metastatic malignancy. When metaplasia is extensive, they can present as thyroid nodule. Differentiation of FNAC related squamous metaplasia from malignancy is very necessary to choose appropriate treatment. Cholesterol granulomas are extremely rare in thyroid. Cases have been reported as Cholesterol granuloma in association with primary lipid metabolism disorders like Erdheim- Chester disease (ECD), can also be post inflammatory finding or some reported literature say it can be a part of WHAFFT [Pandit AA et al;2001]. We aimed our study to determine the incidence of secondary changes seen in cases undergone a previous FNAC as well as secondary diagnosis missed on FNAC. We reviewed cases over a period of one month where we had the FNAC findings as well as the biopsy findings and found total 10 cases where we had both the diagnosis out of which 6 showed the desired secondary changes and 1 showed secondary finding missed on FNAC.

Authors and Affiliations

Neema Tiwari

Keywords

EP ID EP494577
DOI -
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