A Case of Hyalinizing Trabecular Adenoma of the Thyroid Gland

Hyalinizing trabecular adenoma of the thyroid gland is a rare benign neoplasm. It is characterized by an encapsulated nodule, trabecular arrangement of polygonal, oval, elongated cells, and hyalinized stroma. It is easily confused with medullary thyroid carcinoma or papillary thyroid carcinoma. Distinguishment with pathologic finding and immunohistochemical studies are needed to make a definite diagnosis. We recently experienced a case of hyalinizing trabecular adenoma of the thyroid gland. A 73-year-old woman present with an incidentally detected left thyroid mass. Fine needle aspiration was performed and papillary thyroid carcinoma was suspected. However, the surgical specimen revealed a hyalinizing trabecular adenoma. We present this case with a review of the literature.

Hyalinizing Trabecular Adenoma of Thyroid

The Hyalinizing trabecular adenoma of the thyroid is a uncommon benign neoplasm which is characterized by trabecular growth pattern with hyaline stroma of the basal membrane type. It is often misdiagnosed as papillary carcinoma due to its peculiar cytologic and histologic features such as, nuclear grooving and papillary structures, or as medullary carcinoma due to the hyalinized stroma resembling amyloid. Special stains and immunohistochemical studies are required to make a definite diagnosis. A 34-year old woman was admitted suffering from a left neck mass. Computed tomography showed a 2 cm-sized mass in the left thyroid. Fine needle aspiration cytology suggested papillary carcinoma. Intraoperative frozen section suggested medullary carcinoma, and H&E staining suggested medullary carcinoma. However according to immunohistochemistry which revealed calcitonin negative, the tumor was reviewed and finally diagnosed as hyaline trabecular adenoma. The hyalinizing trabecular adenoma, although uncommon, is certainly worth consideration in order to avoid being misinterpreted as carcinoma on the basis of individual cytologic and histologic features.

Cytologic Features of Fine Needle Aspirates of Hyalinizing Trabecular Adenoma with Occult Papillary Carcinoma of the Thyroid / 대한세포병리학회지

Hyalinizing trabecular adenoma of the thyroid gland is a rare benign neoplasm predominantly diagnosed in middle-aged women. Carney et al. first described this entity that may mimic paraganglioma, medullary carcinoma and papillary carcinoma in 1987. We describe cytologic and histopathologic features of a case of hyalinizing trabecular adenoma combined with occult papillary carcinoma in the opposite lobe. A 55-year-old woman presented with nontender palpable mass of the right neck for 6 months. The aspirate was cellular and contained small clusters and sheets of epithelial cells with abundant filamentous, vacuolated, and ill-defined cytoplasm. The nuclei were slightly pleomorphic and showed nuclear overlapping, nuclear grooves, and intranuclear cytoplasmic inclusions. Histologic examination showed hyalinizing trabecular adenoma in the right lobe and occult papillary carcinoma in the left lobe.

Hyalinizing Trabecular Adenoma of Thyroid Gland

Hyalinizing trabecular adenoma of the thyroid gland is a distinctive benign epithelial lesion exhibiting a prominent trabecular arrangement and stromal hyalinization. We recently recognized a hyalinizing trabecular adenoma of the thyroid that displayed potentially misleading features of papillary and medullary carcinomas. However the immunohistochemical features, i.e. thyroglobulin-positive and calcitonin-negative as well as its trabecular arrangement and surrounding abundant hyaline materials confirmed our diagnosis.

Fine Needle Aspiration Cytology of the Hyalinizing Trabecular Adenoma of the Thyroid Gland: A Case Report / 대한세포병리학회지

Hyalinizing trabecular adenoma is an uncommon benign thyroid tumor that is recently described in the literature. This tumor is easily confused with medullary carcinoma on surgical specimens and with papillay carcinoma on cytologic specimens. Herein we report the cytologic characteristics of a case of histologically proven hyalinizing trabecular adenoma of the thyroid gland. Cytologically, the aspirate showed trabecular or individually dispersed polygonal cells with finely stippled chromatin pattern, nuclear grooves, and eosinophilic nuclear pseudoinclusions. No colloid materials were noted in the background.

A Case of Hinman Syndrome Complicated by Chronic Renal Failure

Although there have been a few reports of cases in which cancer cells of extrauterine origin were observed in vaginal smears, such findings are relatively uncommon. We recently experienced a case of ovarian serous cystadenocarcinoma diagnosed by cervicovaginal smear in a 56-year-old woman in routine work-up of carcinoma peritonei. The cellular features were several scattered cellular clusters of adenocarcinoma cells in clear background without tumor diathesis. Psammoma body was not present. Exploratory laparotomy confirmed the diagnosis of bilateral ovarian serous cystadenocarcinoma with multiple metastases.

Hyalinizing Trabecular Adenoma of the Thyroid: A case report

We report a case of hyalinizing trabecular adenoma of the thyroid gland with its immunohistochemical and ultrastructural features. A 53 year-old euthyroid woman presented a well defined small cold nodule on a thyroid iodine scan. Microscopically, oval and elongated tumor cells were arranged in trabeculae, clusters and a "zellballen" pattern resembling paraganglioma with scattered follicles. Nuclear features were characterized by fine nuclear grooves, acidophilic intranuclear cytoplasmic inclusions and perinucleolar halos. Abundant extracellular eosinophilic fibrohyaline matrix resembling amyloid were also noted. Immunostaining of tumor cells was positive for thyroglobulin and negative for calcitonin. In addition, tumor cells displayed an unexpected, unique cytoplasmic immunoreactivity for MIB1. Electron microscopy revealed euchromatic nuclei with grooves, intranuclear cytoplasmic inclusions, intermediate filament stuffed cytoplasms and abundant extracellular basal lamina material.