Tumors of the thyroid gland: histologic and cytologic features--part 1

Papillary thyroid cancer, macrofollicular variant: the follow-up and analysis of prognosis of 5 patients

Objective. The main aim of this study was to comparatively analyze the recurrence and prognosis of this rare variant with the literature by analyzing the follow-up data of 5 patients diagnosed with papillary cancer macrofollicular variant. Methods. The demographic data, radiological and pathological data, and prognostic data of 5 patients who underwent surgery for thyroid cancer and were diagnosed with papillary cancer macrofollicular variant pathologically were retrospectively analyzed. Results. The mean age of patients whose mean follow-up period was determined as 7.2 years was 41, and the male/female ratio was 4/1. All patients underwent total thyroidectomy. The pathology report of 2 patients (40%) revealed macrofollicular variant of papillary microcancer, and 3 patients papillary cancer macrofollicular variant. Central dissection was performed in one patient (20%) due to macroscopic pathologic lymph node and 4 metastatic lymph nodes were reported. Also, locoregional recurrence was present in 3 out of 5 patients (60%). Conclusions. Although an impression of earlier and increased risk of recurrence in papillary carcinoma with macrofollicular variant has been documented, more studies with extensive follow-up times and large populations are required.

Differential expression of immune-modulatory molecule HLA-E in non-neoplastic and neoplastic lesions of the thyroid

Human leukocyte antigen (HLA)–E is a non-classical molecule of the histocompatibility complex that functions as one of the main ligands of the Natural Killer (NK) cell inhibitory receptor CD94/NKG2A and inhibits its potent cytotoxic activity. Due to the important role of NK cells in combating neoplasm, we hypothesized that the differential expression of HLA-E could favor the progression of heterogeneous thyroid tumors.Using an immunohistochemistry technique in 143 biopsies of thyroid tumors, including benign and malignant neoplasms and goiters, we evaluated the expression of HLA-E among various tumor types and its association with the clinicopathological factors of diseases. We verified high HLA-E expression in all types of neoplastic tumors, although no significant differences between the groups were found. Low expression was observed in 95 percent of the goiter samples, showing significant differences between neoplastic and non-neoplastic lesions. Furthermore, a significant result was found with regard to the tumor size, with high HLA-E expression being related to smaller tumors. Therefore, our data suggest that an increase in HLA-E may be associated with the establishment of thyroid neoplasms, with either benign or malignant features.

Role of Fine-needle Aspiration Biopsy and Frozen Section in the Management of Papillary Thyroid Carcinoma Subtypes

Since fine-needle aspiration biopsy (FNAB) was introduced, the value of frozen section (FS) has been questioned. This study compares FNAB and FS sensitivities among the usual form of papillary thyroid cancer (uPTC) and variants of PTC such as tall cell (tcPTC), follicular (fPTC), and Hurthle cell (HcPTC). A total of 257 patients who underwent preoperative FNAB, intraoperative FS, and thyroidectomy for PTC were, randomly selected from a database of a university teaching hospital in Toronto. There were 218 females (84.8%) and 39 males (15.2%), from 19 to 89 years of age (mean of 44 years), having uPTC (n = 212), fPTC (n = 24), HcPTC (n = 14), and tcPTC (n = 7). Data were analyzed using chi2 test. Sensitivities were calculated by division of true positives and by the sum of true positives and false negatives. True positives had to reflect a conclusive diagnosis of cancer. The FNAB sensitivities were uPTC (39.2%), fPTC (25%), HcPTC (42.9%), tcPTC (85.7%), similar to FS sensitivities (p = 0.497) for uPTC (44.3%), fPTC (16.7%), HcPTC (42.9%), and tcPTC (71.4%). Use of FS following FNAB increased sensitivities for uPTC to 56.1%, fPTC to 29.2%, and tcPTC to 100%. In addition, FS did not increase FNAB sensitivity in HcPTC. Combination FNAB plus FS failed in 43.9% of uPTC, 70.8% of fPTC, and 57.1% of HcPTC. We concluded that FNAB and FS sensitivity vary with PTC subtype and are still necessary for selection and treatment. The recognition of morphologic subtypes of PTC from the FNAB could optimize the selection of patients for intraoperative FS, enhance the preoperative assessment of prognosis, facilitate the surgical planning, and simplify the preparation of postoperative adjuvant therapy.

Evaluation of the thyroid nodule

BACKGROUND

Clinically detectable thyroid nodules occur in up to 4% of the population in the United States. With ultrasound, nodules may be found in up to 50% of those over 50 years of age.

METHODS

The author reviews his own experience as well as that of others to define a sound clinical approach to the differential diagnosis and detection of thyroid cancer.

RESULTS

Prior neck irradiation is a risk factor for thyroid malignancy. The association of a thyroid nodule with enlarged lymph nodes or fixation of the nodule to strap muscles or the trachea suggests malignancy. A diffusely multinodular gland is usually benign.

CONCLUSIONS

Thyroid function tests rarely help a differential diagnosis. Fine-needle aspiration is the "gold standard" for diagnosis. Tiny "incidentalomas" are often followed with repeat monitoring for change of size or character.