The significance of paravacuolar granules of the thyroid. A histologic, cytologic and ultrastructural study.
ABSTRACT The presence of the so-called "paravacuolar granules" in thyroid follicular cells has been associated with increased metabolic activity of the gland, regressive changes, degeneration, phagocytic activity and benign papillary hyperplasia. During the course of a review of the intraoperative cytologic preparations and corresponding histologic sections from 73 thyroid cases, the presence of granules within follicular cells was noted in 25 cases (18 adenomatous or colloid goiters, 3 follicular adenomas, 2 papillary carcinomas, 1 follicular carcinoma and in thyroid tissue surrounding a follicular adenoma in 1 case). Histochemical and ultrastructural studies showed the granules to consist of lysosomes containing hemosiderin or lipofuscin pigments. These findings indicate that the presence of paravacuolar granules in thyroid cells is a common nonspecific finding that simply reflects: (1) the erythrophagocytic capability of the follicular epithelial cells, which results in the accumulation of iron within lysosomes, and (2) the accumulation of lipofuscin pigments within lysosomes as a result of degradation of endogenous cellular material.
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ABSTRACT: A comprehensive comparative histo-cytological study of 48 nodular goiters from an endemic goiter region was undertaken. Practically all features observed on the biopsies were identified, although with less frequency, on the smears. In agreement with previous observations, characteristic components of nodular goiter (NG) in aspirates included small to medium size epithelial cells with regular round nuclei, honeycomb pattern, large follicles, papillae showing the previously mentioned epithelial features, oxyphilic cells, and moderate to abundant background colloid material and thyroid phagocytes (macrophages). All eight features occurred together in only 2% of the studied cases, seven in 6 (12.5%), six in 4 (8%), five in 6 (12.5%), four in 12 (25%), three in 6 (12.5%), two in 11 (23%), and one in 2 (4%) cases, respectively. Regardless of the number and combination of features present, specific identification of NG on the smears may not always be possible and diagnostic pitfalls include thyroid cyst, Hashimoto's thyroiditis, granulomatous lesions, and, more frequently, follicular neoplasia. Our findings suggest that thyroid aspirates should be analysed with critical clinico-pathological approach and surgery considered only for nodules that are clinically suspicious or unresponsive to hormonotherapy when a diagnosis of follicular neoplasia is made.Diagnostic Cytopathology 07/1992; 8(4):409-19. DOI:10.1002/dc.2840080421 · 1.52 Impact Factor
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ABSTRACT: Thyroid nodules are common and, depending on the detection technique used, can affect 50% or greater of the population. The primary diagnostic test to assess the nature of these nodules is fine-needle aspiration cytology. Most thyroid nodules are benign and often are multiple. However, the morphology of these nodules may mimic neoplasms showing features such as papillary growth, micro follicles and even oncocytic metaplasia. Lesions with these features may be considered in-determinant, and often require surgical excision to define their nature. The role of cytopathology in this area is to screen those definitely benign nodules, thus preventing surgery and reassuring both the patient and the clinician. In this review, we demonstrate many of the morphological manifestations of nodular goiter and stress the necessity of careful preparatory techniques. Although the past several years have witnessed the development of molecular testing to refine diagnostic cytology in the thyroid, it is still the role of the cytopathologist to identify those "indeterminant" nodules which should be tested. Thus, the cytopathologist contributes both an essential diagnostic and an important cost saving role which hopefully will continue in the future.Best Practice & Research: Clinical Endocrinology & Metabolism 08/2014; 28(4). DOI:10.1016/j.beem.2014.01.010 · 4.91 Impact Factor
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ABSTRACT: Fine-needle aspiration (FNA) is the predominant method for triaging thyroid nodules into operative and nonoperative lesions. Accurate needle placement assuring representative sampling of a suspicious nodule is required. Criteria are well established for separation of nodular goiter from most neoplasms but are less well developed for recognition of normal thyroid tissue. Identification of normal tissue is vital when investigating solitary nodules. Cytologic identification of only normal thyroid tissue would indicate a failure to sample the index nodule. The authors investigated a set of criteria to determine whether any were useful for separating goiterous nodules from normal thyroid tissue. FNA specimens from 10 patients with histologically confirmed goiters were compared with bench aspirates from 7 nodular goiters and 9 thyroid specimens that showed no histologic change. The three sets of specimens were scored for 21 cytomorphologic variables, and differences in the frequency of the variables between sets of FNA specimens were recorded. The patient specimens were compared with bench specimens to find differences secondary only to in vivo and in vitro specimen types. These features were excluded from analysis of differences between bench specimens of hyperplastic nodules and normal tissue. Cells with feathered cytoplasmic edges occurred with statistically significantly different frequency between bench specimens and patient goiter specimens. Cytomorphologic features that showed differences between FNA specimens from goiters and normal thyroid tissue included the presence of microfollicles, prominent nucleoli, abundant cytoplasm, the number of cells with paravacuolar granules, the presence of Hürthle cells, and the presence of cells with feathered cytoplasmic edges. The results of the current study indicate that there are cytologic differences between FNA specimens from normal thyroid and from goiterous nodules. The presence of Hürthle cells, prominent nucleoli, and cells with abundant cytoplasm favored the diagnosis of nodular goiter, whereas large numbers of cells with paravacuolar granules favored a determination of histologically normal thyroid. These differences may aid in the distinction of normal thyroid tissue from hyperplastic goiters in cytologic specimens obtained by FNA.Cancer 08/2003; 99(4):217-22. DOI:10.1002/cncr.11221 · 4.90 Impact Factor