Cytological features of dyshormonogenetic goitre: A diagnostic pitfall

Abstract

Dyshormonogenetic goitre, being rare, infrequently reaches the cytopathologist's desk. This letter reports a case of a child with dyshormonogenetic goitre, highlighting its cytological features and common differential diagnoses.Dyshormonogenetic goitre (DG) is a rare cause of congenital hypothyroidism, resulting from a lack of enzymes necessary for biosynthesis/transport of thyroid hormones. The disease usually presents in childhood with symptoms secondary to hypothyroidism.Rarely, patients may be euthyroid. Owing to a lack of adequate thyroid hormone synthesis, there is uninhibited stimulation by thyroid stimulating hormone (TSH), resulting in thyroid hyperplasia, and hence thyroid swelling. This profound thyroid follicular hyperplasia can be a cause of over-diagnosis in fine needle aspiration cytology (FNAC). 1 Although the histological findings of DG are well documented, there is a paucity of literature on its cytological features as DG is usually a clinical diagnosis. However, patients may be subjected to FNAC for evaluation of either radiologically suspicious nodules or thyromegaly in an unsuspected euthyroid patient. An accurate pre-operative diagnosis on cytology, will aid correct management and avoid undue surgery. We present here the cytological and histological findings of a case of DG along with a discussion of the possible diagnostic pitfalls that this lesion may pose.An 8-year-old male presented with gradual thyroid enlargement and growth retardation from 5 years of age. The T3 (0.78 ng/mL) and T4 (1.6 μg/dL) levels were decreased, and the TSH (584-753 μIU/mL) was markedly raised. Sonography showed multinodular thyroid enlargement. The nodules were solid and hyperechoic relative to the surrounding parenchyma. Some showed cystic changes. Contrastenhanced computed tomography scan showed multiple non-enhancing well defined round to oval shaped hypo-intensities in both lobes of thyroid. Thyroid scintiscan showed a cold nodule in the inferior pole of the right thyroid lobe and another in the upper pole of the left thyroid lobe. Ultrasound-guided FNAC was performed on the two nodules using a 24-gauge needle. The smears were air-dried for May-Grünwald Giemsa and alcohol-fixed for Papanicolaou staining.Following cytological evaluation, the patient was subjected to a total thyroidectomy for cosmetic purposes, and thereafter put on hormone replacement. The thyroidectomy specimen weighed 10 g and measured 4.5 × 6 × 3 cm 3 . The external capsule was intact. The cut surface of both lobes showed solid, greyish-white well circumscribed nodules ranging in size from 0.4 to 1 cm separated by fibrous bands.The smears were cellular and showed syncytial fragments and cohesive clusters of follicular cells. Occasional stromal fragments were seen ( Figure 1A), corresponding to stromal fibrosis on histology. (Figure 1E). The follicular cells were arranged as microfollicles ( Figure 1B), representing follicular hyperplasia seen histologically ( Figure 1F). There was focal nuclear anisonucleosis with a moderate number of giant...

Cytomorphologic analysis of dyshormonogenetic goiter

“…6 The underlying cause of the inborn metabolic error is a defect in thyroid hormone synthesis that may be because of defects in Only four case reports have described the cytological findings of dyshormonogenetic goiter. [2][3][4][5][6] By comparing the cytomorphological features of these cases and this case, we observed that the majority (83.3%) showed syncytial and microfollicular arrangement of follicular epithelial cells, nucleomegaly and nuclear hypochromasia. Half of the cases noted empty follicles, nuclear overlap/crowding, and colloid.…”

“…However, cytological features were reported in only four case reports of dyshormonogenetic goiter. [2][3][4][5] We present a case of dyshormonogenetic goiter in a 9-yearold girl. We compared our case with other similar case reports in the literature to elaborate on the cytomorphological features of this benign entity.…”

Congenital hypothyroidism and thyroid cancer

“…Adequate cytological diagnosis in nodules of patients with dyshormonogenesis might be demanding as a result of specific architectural and cytological appearances that may lead to an erroneous interpretation of the malignancy. The main findings are summarized in Table 2 (Matos et al 1994, Mahajan et al 2019. The cytological approach needs much refinement, encompassing the discernment of many conditions, such as hyperplastic nodule, post-radioiodine changes, follicular neoplasm, and non-invasive follicular thyroid neoplasm with papillary-like nuclear features (Matos et al 1994, Mahajan et al 2019.…”

“…The main findings are summarized in Table 2 (Matos et al 1994, Mahajan et al 2019. The cytological approach needs much refinement, encompassing the discernment of many conditions, such as hyperplastic nodule, post-radioiodine changes, follicular neoplasm, and non-invasive follicular thyroid neoplasm with papillary-like nuclear features (Matos et al 1994, Mahajan et al 2019. There may also be foci of papillary hyperplasia and mitotic activity, which could again lead to overdiagnosis of DTC.…”

“…There may also be foci of papillary hyperplasia and mitotic activity, which could again lead to overdiagnosis of DTC. It is not rare for the cytological conclusion to be atypia of undetermined significance/follicular lesion of undetermined significance, combined with focal cytological and architectural atypia (Matos et al 1994, Mahajan et al 2019. Hence, the histological examination must be largely scrupulous since lifelong TSH stimulation might be a powerful driver of many architectural changes and cellular pleomorphism (Table 2) (Ghossein et al 1997, Fadda et al 1999, Pedrinola et al 2001, Deshpande & Bobhate 2005, Drut & Moreno 2009, Kallel et al 2009.…”