Insular carcinoma of the thyroid: report of a case with intact insulae and microfollicular structures

Breast metastases from extramammary malignancies: typical and atypical ultrasound features

Breast metastases from extramammary malignancies are uncommon. The most common sources are lymphomas/leukemias and melanomas. Some of the less common sources include carcinomas of the lung, ovary, and stomach, and infrequently, carcinoid tumors, hypernephromas, carcinomas of the liver, tonsil, pleura, pancreas, cervix, perineum, endometrium and bladder. Breast metastases from extramammary malignancies have both hematogenous and lymphatic routes. According to their routes, there are common radiological features of metastatic diseases of the breast, but the features are not specific for metastases. Typical ultrasound (US) features of hematogenous metastases include single or multiple, round to oval shaped, well-circumscribed hypoechoic masses without spiculations, calcifications, or architectural distortion; these masses are commonly located superficially in subcutaneous tissue or immediately adjacent to the breast parenchyma that is relatively rich in blood supply. Typical US features of lymphatic breast metastases include diffusely and heterogeneously increased echogenicities in subcutaneous fat and glandular tissue and a thick trabecular pattern with secondary skin thickening, lymphedema, and lymph node enlargement. However, lesions show variable US features in some cases, and differentiation of these lesions from primary breast cancer or from benign lesions is difficult. In this review, we demonstrate various US appearances of breast metastases from extramammary malignancies as typical and atypical features, based on the results of US and other imaging studies performed at our institution. Awareness of the typical and atypical imaging features of these lesions may be helpful to diagnose metastatic lesions of the breast.

Insular thyroid carcinoma: a retrospective clinicopathologic study

BACKGROUND

Poorly differentiated carcinoma is a rare epithelial tumor that falls between well-differentiated thyroid carcinoma and anaplastic thyroid carcinoma in terms of morphologic appearance and biologic behavior. An insular variant was characterized in 1983. Further study of this neoplasm is warranted owing to its high aggressiveness, propensity to local recurrence and distant metastases, and high associated mortality. Since insular thyroid carcinoma may have varied presentations, treatment should be individualized.

PURPOSE

To describe the experience of a major tertiary medical center with insular thyroid carcinoma over a 7-year period.

MATERIAL AND METHODS

The study sample consisted of 17 patients with poorly differentiated thyroid cancer, insular variant, who were treated and followed at the Department of Otolaryngology, Head and Neck Surgery of Rabin Medical Center, Israel, in 1992-2009. The medical files were reviewed for background data, clinicopathologic features, treatment, and outcome.

RESULTS

The study group included 10 men and 7 women with a mean age of 63 years (range 16-78). Initial treatment was total thyroidectomy, in a single session (n=9) or two sessions (n=8), followed by radioiodine ablation. In addition, five patients received postoperative external beam radiation and one patient received chemotherapy. Nine patients had extrathyroidal extension, seven had vascular invasion, and four had multifocal disease. Distant metastases were present in four patients. Follow-up ranged from 6 months to 12 years. At present, 11 patients are alive and well. Five died of disease, and one died of another cause.

CONCLUSION

Insular thyroid carcinoma is aggressive and difficult to treat. Surgery remains the mainstay of treatment, though multimodality therapy is usually required.

Poorly differentiated (insular) thyroid carcinoma arising in a long-standing colloid goitre: A cytological dilemma

Poorly differentiated (insular) thyroid carcinoma (PDITC) is an uncommon thyroglobulin producing neoplasm intermediate in aggressiveness between well-differentiated carcinomas of follicular cell origin and undifferentiated anaplastic carcinoma. Its cytomorphological recognition is essential for planning surgery and subsequent management as it is known for its aggressive behavior, advanced stage at presentation, local recurrences and rapid dissemination. We report a case of PDITC arising in a long-standing goiter, in which presence of microfollicular structures and minimal necrosis resulted in difficulty in distinguishing it from a follicular neoplasm of thyroid.

Insular variant of poorly differentiated thyroid carcinoma

OBJECTIVE

To present a case of an insular variant of poorly differentiated thyroid carcinoma (PDTC) and to review the literature related to diagnosis, natural history, and treatment of this unusual form of thyroid cancer.

METHODS

We present the clinical, laboratory, and pathologic findings of the study patient and review English-language literature related to PDTC published between 1970 and the present.

RESULTS

PDTC is a controversial and rare epithelial thyroid cancer, intermediate between differentiated thyroid carcinoma and anaplastic thyroid carcinoma that exhibits increased aggressiveness, propensity to local recurrence, distant metastases, and increased mortality. PDTC warrants aggressive management with total thyroidectomy followed by radioactive iodine ablation and potentially additional therapy for residual or recurrent disease. Some carcinomas do not take up radioactive iodine, and dedifferentiated clones of distant metastases may evolve. It is unclear whether chemotherapy is beneficial. Use of additional imaging modalities, including positron emission tomography, 18-fludeoxyglucose positron emission tomography/computed tomography, 18-fludeoxyglucose positron emission tomography/computed tomography/magnetic resonance imaging, (124)I positron emission tomography/computed tomography, positron emission tomography/magnetic resonance imaging fusion studies, and recombinant human thyrotropin-stimulated radioactive iodine uptake for cancer surveillance are discussed.

CONCLUSIONS

PDTC is an unusual and aggressive form of thyroid cancer. Fine-needle aspiration cytology may not yield sufficient information to specifically diagnose PDTC. Aggressive management with total thyroidectomy and neck dissection followed by high-dose radioactive iodine remnant ablation is standard. Iodine I 131 whole body scanning is often the initial test for tumor surveillance, with other imaging modalities applied as needed.

Cytomorphologic features of poorly differentiated thyroid carcinoma: a multi-institutional analysis of 40 cases

BACKGROUND

Poorly differentiated thyroid carcinoma (PDTC) is an uncommon and aggressive malignancy. Despite the significant clinical implications of a diagnosis of PDTC, its cytomorphologic features have not been well defined. Statistical analysis was applied to a series of 40 PDTCs to identify a specific set of cytomorphologic features that characterized these tumors on fine-needle aspiration biopsy (FNAB).

METHODS

In total, 40 thyroid FNABs that were highly diagnosed histologically as PDTC (19 insular carcinomas and 21 noninsular carcinomas) comprised the study group. A control group of 40 well differentiated thyroid neoplasms were selected for comparison. All FNABs were reviewed and scored for a series of 32 cytomorphologic features. The results were evaluated using univariate and stepwise logistic regression (SLR) analyses.

RESULTS

In univariate analysis, 17 cytomorphologic features were identified that characterized the 40 PDTCs: insular, solid, or trabecular cytoarchitecture (P < .001); high cellularity (P = .007); necrosis (P = .025) or background debris (P = .025); plasmacytoid appearance (P = .0007); single cells (P < .0001); high nuclear/cytoplasmic ratio (P < .0001); scant cytoplasm (P = .03); nuclear atypia (P < .0001), including nuclear pleomorphism (P = .0052) and anisokaryosis (P < .0001); granular/coarse chromatin (P = .026); naked nuclei (P = .01); mitotic activity (P = .0001) and apoptosis (P < .0001); endothelial wrapping (P = .0053); and severe crowding (P < .0001). In logistic regression analysis, severe crowding (P = .0008) and cytoarchitecture (P < .0001) were identified as the most significant cytomorphologic features of PDTCs, and the combination of cytoarchitecture, severe crowding, single cells, and high nuclear/cytoplasmic ratio was the most predictive of PDTC.

CONCLUSIONS

PDTCs have characteristic cytomorphologic features. By using logistic regression analysis, the features that were identified as the most predictive of PDTC were severe crowding, insular/solid/trabecular morphology, single cells, and high nuclear/cytoplasmic ratio.

Poorly differentiated thyroid carcinoma: a cytologic-histologic review

The term poorly differentiated thyroid carcinoma (PDTC) was first proposed in the 1980s, but it was not definitively recognized as a distinct pathologic entity until the most recent classification of endocrine tumors by the World Health Organization in 2004. More recently, as a result of discussions in Turin, Italy, in 2006, diagnostic criteria were made more specific by a consensus of expert thyroid pathologists. The histologic and cytologic aspects are detailed with particular attention to key features helpful in the diagnosis of PDTC, both in surgical pathology and in cytology-based studies. Histologically, insular, solid, and/or trabecular architecture, along with at least one of the following: convoluted nuclei, mitotic activity (>3/10 HPF), or tumor necrosis, are required for a diagnosis of PDTC. Cytologically, the combination of insular, solid, or trabecular cytoarchitectural pattern, single cells, high nuclear to cytoplasmic (N/C) ratio, and severe crowding are highly suggestive of PDTC. Most PDTCs are immunohistochemically positive for thyroglobulin and thyroid transcription factor 1 (TTF-1), and a subset is also positive for p53. On the molecular level, ras mutations are the most common finding. PDTCs are managed aggressively by total thyroidectomy, I, and in some cases, external beam radiotherapy.

Insular carcinoma of the thyroid with uncommon cytologic features: anisokaryotic cells and microfollicles containing dense colloid

Insular carcinoma of the thyroid is a rare neoplasm, constituting less than 5% of all thyroid tumors. It was Carcangiu et al. who first described this tumor, which exhibits an intermediate biologic behavior between well-differentiated and undifferentiated follicular carcinomas, as a distinct clinicopathologic entity. A 63-year-old female patient with thyroid enlargement was admitted to our institution. Thyroid ultrasonography revealed a 5x4x3cm solid nodule within the right thyroid lobe. The fine needle aspiration was highly cellular; there were individual cells with naked nuclei, loose aggregates, cohesive clusters of follicular cells and infrequent microfollicles with round-oval nuclei containing finely granular chromatin, and scant cytoplasm. There were two uncommon findings not previously reported in the literature. The first one is anisokaryotic nuclei, and the second one is the presence of dense colloid in the center of microfollicles. The aspiration biopsy was reported as malignant. The patient underwent bilateral total thyroidectomy. Histopathologically, the lesion was diagnosed as insular carcinoma. We believe that in addition to the previously described cytopathologic findings, microfollicles with dense colloid core and anisokaryosis may be indicators of insular carcinoma in thyroid FNACs.

Cytologic features of insular carcinoma of the thyroid: A case report

Fine-needle aspiration of the thyroid has been accepted as one of the initial diagnostic tools in the evaluation of thyroid nodules. As its use becomes more widespread, the demand for more precise diagnosis has increased. The histopathology of insular carcinoma of the thyroid is now well recognized. However, the cytologic diagnostic criteria are not well established. The reported series have been small (4-6 cases), which is not surprising because of the rarity of this tumor. They consist of retrospective reviews of the aspirates (after the histologic diagnosis had been made from the thyroidectomy specimens). Also, the case reports do not provide uniform cytologic criteria; this could be due to limited sampling of these tumors (which are usually large). A cytologic diagnosis of insular carcinoma can be suggested if multiple samples of a thyroidal mass are markedly cellular, with a cytologic pattern reminiscent of a follicular variant of papillary carcinoma. However, the follicular cells are arranged predominantly in rosettes, their nuclei appear more monotonous, some "intranuclear cytoplasmic pseudoinclusions" are seen, and there is an occasional large cell with a pleomorphic nucleus.

Insular carcinoma of the thyroid in an adolescent: a case report and review of the literature

A 15-year-old girl was referred for a thyroid gland mass, which rapidly enlarged in the brief interval between initial evaluation and surgery. Fine needle aspiration of the mass suggested a diagnosis of papillary thyroid carcinoma. Upon pathological examination of this aggressive tumor, an "insular" pattern of tumor was identified. Insular carcinoma of the thyroid gland is unusual in the pediatric age group, however its aggressive nature and prognosis have important management implications for those physicians involved in the care of affected patients. Aggressive surgical debulking, very close observation of the course of disease, and adjunctive radioiodine therapy may all be indicated as were performed in this case. A description of the pathology of this condition, and a review of the clinical experience with insular carcinoma in childhood and adolescence are presented.

Insular Carcinoma of the Thyroid

Thyroid surgeons are becoming increasingly more aware of a histologically distinct subset of thyroid carcinoma whose classification falls between well-differentiated and anaplastic carcinomas with respect to both cell differentiation and clinical behavior. This subtype of tumors has been categorized as poorly differentiated or insular carcinoma, based on its characteristic cell groupings. Although the differentiation of insular carcinoma from other thyroid carcinomas has important prognostic and therapeutic significance, relatively little about insular carcinoma has been published in the otolaryngology literature. In this article, we describe a new case of insular carcinoma and we discuss the findings of our review of the literature. We conclude that insular thyroid carcinoma warrants aggressive management with total thyroidectomy followed by radioactive iodine ablation of any remaining thyroid tissue.

Cytopathology of insular carcinoma of the thyroid

Four pure insular carcinomas (IC) and one IC with focal anaplastic carcinoma (AC) of the thyroid with cytologic evaluation by fine-needle aspiration (FNA) were reviewed. The needle aspirates from the four pure ICs revealed abundant monomorphic follicular cells present singly, in small, loose aggregates, and in cohesive trabecular and acinar clusters. Tumor cells showed fragile, ill-defined, granular cytoplasm and oval nuclei with conspicuous or inconspicuous nucleoli. The case of IC with focal AC yielded, in addition to the follicular cells as seen in the FNA of the 4 cases of pure IC, large pleomorphic malignant cells with prominent nucleoli that were characteristic for an AC, giant-cell type. No intact insulae of tumor cells were identified in any of the 5 cases. Thus, a thyroid IC may be suspected if abundant cohesive and dyshesive monomorphic follicular cells are present in the tumor FNA. However, a firm diagnosis of thyroid IC can only be made by histologic examination of the excised tumor.