Hypercalcemia of Malignancy with Simultaneous Elevation in Serum Parathyroid Hormone-Related Peptide and 1,25-Dihydroxyvitamin D in a Patient with Metastatic Renal Cell Carcinoma

ObjectiveTo determine the cause of refractory hypercalcemia in a patient with metastatic renal cell carcinoma.MethodsWe describe the clinical, pathologic, and immunostain findings in a patient with metastatic renal cell carcinoma and hypercalcemia of malignancy refractory to intravenous bisphosphonates.ResultsA 57-year-old man with a remote history of clear cell renal cell carcinoma was referred to our clinic for evaluation of resistant hypercalcemia 12 years after nephrectomy. The patient had simultaneous elevation of serum 1,25-dihydroxyvitamin D and parathyroid hormone-related peptide. Computed tomographic scan of the chest and abdomen demonstrated numerous ring-enhancing lesions in the liver, and histologic examination of a biopsy specimen revealed liver tissue infiltrated by a malignant neoplasm composed of cells with clear and eosinophilic cytoplasm, arranged in tubules and nests. Findings were morphologically consistent with renal cell carcinoma of clear cell type, and positive immunostaining with the epithelial markers EMA and CAM 5.2 were supportive of the morphologic impression of renal cell carcinoma. The tumor showed expression of 25-hydroxyvitamin D 1a-hydroxylase by immunostaining. After failing to respond to intravenous bisphosphonates, the hypercalcemia improved with prednisone treatment.ConclusionsIn some patients with renal cell carcinoma, hypercalcemia of malignancy is associated with simultaneous elevation in serum 1,25-dihydroxyvitamin D and parathyroid hormone-related peptide. As our case exemplifies, it is imperative to identify such patients because hypercalcemia due to elevated 1,25-dihydroxyvitamin D levels may respond better to glucocorticoid treatment than to the conventional bisphosphonate therapy. (Endocr Pract. 2009;15:234-239)     

Renal cell carcinoma metastatic to follicular adenoma of the thyroid gland. A case report

BACKGROUND: Renal cell carcinoma is an unpredictable tumor that can recur many years after the original diagnosis and metastasize to uncommon sites, including the thyroid gland. Differential diagnosis from primary thyroid tumor is often difficult both clinically and pathologically. We report a case of metastatic renal cell carcinoma in follicular adenoma of the thyroid gland. CASE: A 48-year-old woman presented with a 3-cm-diameter, palpable mass in the left lobe of the thyroid gland. The patient's history included removal of a left renal mass, which was conventional renal cell carcinoma. Fine needle aspiration cytology smears contained a few small clusters of polygonal cells with abundant, clear cytoplasm and irregular, hyperchromatic nuclei as well as bland-looking thyroid follicle cells and stromal cells. A papillary or follicular growth pattern was not detected. A cell block made from the aspirated sample was composed mainly of clear cells. By immunohistochemical stains, the clear cells were completely negative for TTF-1, thyroglobulin, calcitonin and inhibin while equivocally staining for cytokeratin, CD10 and galectin-3. The histologic diagnosis was renal cell carcinoma metastatic to follicular adenoma of the thyroid gland. CONCLUSION: Renal cell carcinoma metastatic to the thyroid may masquerade as a primary thyroid neoplasm. A history of prior nephrectomy, the presence of unremarkable thyroid follicle cells, the absence of a papillary or follicular growth pattern and immunohistochemical study can help differentiating metastatic renal cell carcinoma from a primary thyroid lesion with clear cell change.     

Clinical Characteristics and Pituitary Dysfunction in Patients with Metastatic Cancer to the sella

ObjectiveMetastatic disease to the sella is uncommon and there are limited available data regarding the clinical aspects of this disease. We therefore sought to characterize the clinical demographics of sellar metastases.MethodsRetrospective chart review of adults treated at Stanford University Medical Center from 1980 to 2011 with metastatic disease to the sella.ResultsA total of 13 subjects were identified (9 females). The mean age at diagnosis was 55 years (range, 25 to 73 years). A total of 6 patients (46%) had breast car-cinoma, 3 (23%) had renal cell carcinoma, 2 (15%) had squamous cell carcinoma of the head and neck, 1 had bronchoalveolar carcinoma of the lung, and 1 had nodular sclerosing Hodgkin’s lymphoma. The most common presenting signs and symptoms were headache (58%), followed by fatigue (50%), polyuria (50%), visual field defects (42%), and ophthalmoplegia (42%). Seventy-five percent of patients presented with at least one pituitary hormone insufficiency, which included 6 patients (50%) with diabetes insipidus (DI). Eight (67%) subjects had secondary hypothyroidism and 5 (45%) had secondary adrenal insufficiency. Of the patients with stalk involvement, 86% had DI. All patients had a prior diagnosis of malignancy, with a mean duration of 95 months.ConclusionThe most common neoplastic sources to the sella were breast and renal cell carcinomas. Secondary hypothyroidism was the most common endocrine abnormality, followed by DI and adrenal insufficiency. Newonset central hypothyroidism and DI along with known malignancy in a patient with a sellar lesion should raise the suspicion of a metastatic source. (Endocr Pract. 2013; 19:914-919)     

Hürthle cell Thyroid Carcinoma Presenting as A “Hot” Nodule

ObjectiveTo report an unusual clinical scenario and a rare histopathologic finding of Hürthle cell thyroid carcinoma in a patient with an autonomous thyroid nodule.MethodsWe describe the presentation and clinical course leading to the surprising histopathologic diagnosis of Hürthle cell carcinoma in a pediatric patient who was diagnosed with hyperthyroidism presenting as a solitary toxic nodule.ResultsA 13-year-old white girl presented with a recent history of a palpable thyroid nodule during a routine primary care clinic visit. She was asymptomatic, and thyroid function tests revealed a suppressed thyrotropin concentration, high-normal free thyroxine concentration, and elevated triiodothyronine concentration. The patient underwent dedicated thyroid ultrasonography revealing a 3.5-cm complex mass in the left lobe with increased central vascularity. Iodine 123 imaging of the thyroid demonstrated homogenous, hyperintense activity in the left lobe. The right lobe was not visualized. A solitary toxic nodule was diagnosed, and, considering her age, she was referred for surgical management. The patient underwent a left lobectomy with isthmusectomy. Pathologic examination revealed a 5-cm, encapsulated, well-differentiated Hürthle cell carcinoma with negative margins and no lymphovascular invasion. The patient underwent subsequent completion thyroidectomy with no evidence of residual carcinoma in the right thyroid lobe.ConclusionsMalignancy in autonomously functioning thyroid nodules is rare. Most of the thyroid nodules presenting as “hot” on radioiodine scintigraphy are benign follicular adenomas. However, this case represents a rare clinical entity, and it highlights the need for clinicians to be vigilant and aware that occasionally carcinomas can masquerade as scintigraphic “hot” nodules. (Endocr Pract. 2011;17:e68-e72)     

Renal clear cell carcinoma metastasis to the breast ten years after nephrectomy: a case report and literature review

Background

Renal cell carcinoma most commonly metastasizes to the lungs, skeleton or liver. Metastatic renal cell carcinoma to the breast is very rare, especially for clear cell carcinoma, and few cases regarding this condition have been reported.

Case Presentation

The case we presented was a 68-year-old Chinese female with metastatic renal clear cell carcinoma of the left breast 10 years after a nephrectomy. Identification of the metastatic renal clear cell carcinoma in the breast required multiple breast imaging modalities. Imaging showed a single, ovary-shaped, well-defined hypo-echoic mass, with abundant blood flow on ultrasound images. The mass was enhanced early on MRI, and it was hypointense on a T1-weighted image and hyperintense on a fat-saturated T2-weighted image. Following surgical excision of the tumor, a routine immunohistochemistry antibody panel on the tumor cells revealed negative staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (Her-2). Strong positive staining for the cluster of differentiation 10 (CD10) and vimentin was present.

Conclusion

This case is unusual because of the site of metastatic progression. It is important for physicians to be aware of this progression so early diagnoses can be made, and appropriate therapeutic planning can be initiated.

     

Delayed treatment of papillary thyroid carcinoma arising from struma ovarii in a patient with history of bilateral salpingo-oophorectomy: a case report

ObjectiveWe present a case of papillary thyroid carcinoma arising from struma ovarii treated erroneously as ovarian adenocarcinoma for more than 3 years.MethodsWe report clinical, surgical, laboratory, and imaging findings of the study patient and review the relevant literature.ResultsA 64-year-old woman was treated for ovarian adenocarcinoma for more than 3 years before it was determined that she likely had papillary thyroid carcinoma arising from struma ovarii. This is the first reported case of thyroid carcinoma arising from struma ovarii in a patient with a history of bilateral salpingo-oophorectomy. Possible etiologies include residual ovarian tissue after oophorectomy, ectopic thyroid, or metastatic thyroid cancer.ConclusionsIt is important to include struma ovarii and thyroid carcinoma arising from struma ovarii in the differential diagnosis, even with a history of bilateral salpingo-oophorectomy. This case emphasizes the importance of effective communication among the pathologist, oncologist, and surgeon to ensure timely initiation of appropriate therapy and reduced patient morbidity. (Endocr Pract. 2012;18:e1-e4)     

Metastatic Struma Ovarii Treated With Total Thyroidectomy and Radioiodine Ablation

ObjectiveTo present a rare case of metastatic struma ovarii, review the related literature, and discuss the management.MethodsA case report of a patient with metastatic struma ovarii is presented. The treatment plan, postoperative care, and follow-up are discussed. We conducted a MEDLINE search of the English-language literature seeking additional cases of metastatic struma ovarii. In addition to the current case, the previous 40 cases of metastatic struma ovarii were reviewed and analyzed.ResultsThe mean age of the patients at presentation was 43 years. All patients underwent resection of the primary tumor. The most common sites of involvement for struma ovarii metastatic disease have been the peritoneum, mesentery, and omentum. After primary tumor resection, a wide range of additional treatments have been used, including chemotherapy, resection of metastatic disease, external beam radiation therapy, and radioiodine ablation.ConclusionIn cases of metastatic struma ovarii, we recommend total thyroidectomy in conjunction with radioiodine scanning and radioiodine ablation. Thyroglobulin levels should be followed as a tumor marker, and diagnostic radioiodine scans should be performed to screen for residual or recurrent disease. Although this treatment strategy is well established for thyroid cancer, long-term outcomes of this treatment for struma ovarii are still unknown. (Endocr Pract. 2009;15:167-173)     

Parathyroid carcinoma arising from four-gland hyperplasia

ObjectiveTo report the use of immunohistochemical staining for parafibromin, APC, and galectin-3 to evaluate the malignant potential of a resected parathyroid specimen in a patient initially presenting with primary hyperparathyroidism attributable to 4-gland hyperplasia, who subsequently developed metastatic parathyroid carcinoma.MethodsWe describe a patient with primary hyperparathyroidism who underwent a 3-gland resection of hypercellular parathyroid glands, with postoperative normalization of her serum calcium and parathyroid hormone levels. She returned 4 years later with recurrent hypercalcemia and underwent partial resection of her remaining hypercellular parathyroid gland, without improvement of her hypercalcemia. Selective venous sampling localized the source as draining into her azygos vein, and metastatic parathyroid carcinoma was ultimately diagnosed.ResultsImmunohistochemical staining for parafibromin, APC, and galectin-3 suggested the malignant potential of the atypical adenoma removed during the patient’s original operation, which is believed to be the source of her metastatic disease. Access to this information by the treating surgeon may have prompted a more extensive en bloc resection or more vigilant follow-up that could have altered the patient’s clinical course.ConclusionImmunohistochemical staining for parafibromin, APC, and galectin-3 can be used to help distinguish the source of metastatic disease in patients with parathyroid carcinoma. Selective venous sampling may help localize metastatic parathyroid carcinoma when the source is otherwise not apparent. (Endocr Pract. 2011;17:e37-e42)     

Be Aware of the Patient With Benign Follicular Thyroid Lesion Histology and Rising Thyroglobulin Level

Objective: The accurate diagnosis of thyroid follicular/Hürthle cell tumors is challenging and a matter of controversy. We present a series of patients in whom a misclassification of follicular/Hürthle cell thyroid lesions as benign has led to devastating clinical outcomes.Methods: The Thyroid Cancer Registry of Rabin Medical Center was screened for patients with metastatic differentiated thyroid carcinoma (DTC) who had been initially diagnosed with benign follicular lesion between 1974 and 2015 and treated with hemithyroidectomy. Clinical, pathologic, and outcome data were collected from the medical files. Adequate pathology specimens, when available, were re-evaluated.Results: Seven patients met the inclusion criteria. The original pathologic diagnosis was follicular adenoma in 4 patients and Hürthle cell adenoma in 3 patients. Five patients had bone metastases, of whom one also had lung metastases and one, liver metastases. One patient had both cervical and lung metastases, and 1 patient had only meta-static neck lymph nodes. Six patients had a final diagnosis of encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC), and 1 patient was diagnosed as having follicular thyroid cancer metastasis by bone biopsy. In 3 of the patients, capsular invasion was detected retrospectively; only 1 patient had evidence of vascular invasion. All 7 patients had high levels of thyroglobulin at diagnosis of metastatic DTC.Conclusion: Misclassification of follicular thyroid lesions as benign may lead to progressive disseminated DTC. To minimize the clinical risk of misdiagnosis, especially if a thorough evaluation of the specimens by an experienced pathologist is unfeasible, we suggest long-term follow-up of serum thyroglobulin levels.Abbreviations: DTC = differentiated thyroid carcinoma; EFVPTC = encapsulated follicular variant of papillary thyroid carcinoma; FVPTC = follicular variant of papillary thyroid carcinoma; NIFTP = noninvasive follicular thyroid neoplasm with papillary-like nuclear features; PTC = papillary thyroid carcinoma     

Neuroendocrine Thymic Carcinoma Metastatic to the Parathyroid Gland that was Reimplanted into the Forearm in Patient with Multiple Endocrine Neoplasia Type 1 Syndrome: A Challenging Management Dilemma

ObjectiveTo describe a unique case of a metastatic thymic carcinoma to the hyperplastic parathyroid gland and to present a challenging management dilemma.MethodsOur patient is 60-year-old, intellectually disabled man with history of the multiple endocrine neoplasia type 1 (MEN1) syndrome, a surgery in 1985 for hypercalcemia with removal of one parathyroid gland, surgery in 2007 with findings of extensively necrotic well differentiated neuroendocrine carcinoma (carcinoid tumor) of the thymus. In 2012, he presented with persistent hypercalcemia (calcium level 11.7 mg/dL [range, 8.6-10.2]), and a parathyroid hormone (PTH) level of 225 pg/mL (range, 15-65 pg/mL). He underwent a repeat neck exploration with removal of 2 small inferior and a large left superior 4.5 × 2.5 × 1.5cm parathyroid glands, all of which showed hyperplasia on intraoperative frozen section. A small portion of the superior gland was reimplanted into the patient’s forearm. Final pathology showed the presence of a focus of neuroendocrine tumor within the left superior parathyroid gland with immunostain identical to the thymic carcinoma. His postoperative PTH level was 14 pg/mL and calcium 8.5 mg/dL. A positron emission tomography – computed tomography (PET-CT) and octreotide scans revealed an extensive metastatic disease within the lung, mediastinum, and bones.ResultsWe decided to leave a portion of the reimplanted parathyroid gland with possible metastatic thymic carcinoid in his forearm because of the presence a widespread metastatic disease and his intellectual disability that would result in noncompliance with calcium replacement in case of permanent hypocalcemia.ConclusionMetastatic thymic carcinoma to the parathyroid gland has never been reported in the literature. We have described the first case and presented a challenging management dilemma. (Endocr Pract. 2013;19:e163-e167)     

Incidental Finding of Metastatic Papillary Thyroid Carcinoma in a Patient with Primary Hyperparathyroidism

ObjectiveTo report on the management of a patient with the rare concurrence of primary hyperparathyroidism and incidentally found metastatic papillary thyroid carcinoma in an adjacent lymph node.MethodsWe present a case report, including scintigraphic and histologic documentation, and a summary of the related literature.ResultsPrimary hyperparathyroidism with concomitant occurrence of nonmedullary thyroid carcinoma is rare, occurring in less than 4% of patients. We report a case of a 53-year-old woman with no prior history of endocrine disease with primary hyperparathyroidism and an incidental finding of a concurrent thyroid carcinoma. In this patient, technetium 99m scintigraphy revealed a parathyroid adenoma beneath the inferior pole of the left thyroid bed. Parathyroidectomy was performed successfully with no complications. The final pathology examination showed a large parathyroid adenoma with an incidental finding of a small adjacent lymph node containing metastatic papillary thyroid carcinoma. The patient subsequently underwent total thyroidectomy, and the pathology evaluation revealed papillary thyroid carcinoma, follicular variant.ConclusionTo our knowledge, this case of concomitant primary hyperparathyroidism and papillary thyroid cancer is unique in the way in which the diagnosis of metastatic papillary thyroid cancer was made. The presence of parathyroid adenoma should not exclude the diagnosis of thyroid carcinoma; therefore, careful thyroid evaluation should be considered for all patients with primary hyperparathyroidism. (Endocr Pract. 2007;13:380-383)     

Fine needle aspiration biopsy of three cases of squamous cell carcinoma presenting as a thyroid mass: cytological findings and differential diagnosis

M. Rosa and K. Toronczyk Fine needle aspiration biopsy of three cases of squamous cell carcinoma presenting as a thyroid mass: cytological findings and differential diagnosis Objective: Primary squamous cell carcinomas of the thyroid gland are extremely rare, comprising about 1% of thyroid malignancies. Although squamous cell carcinomas are readily identified as such on aspiration cytology in the majority of cases, the differentiation of primary versus metastatic tumour might not always be easy. Herein, we report three cases of squamous cell carcinomas involving the thyroid gland. Methods: Fine needle aspiration cytology (FNAC) was performed in three patients with a thyroid mass using standard guidelines. Smears were stained with Diff‐Quik and Papanicolaou stains. Results: Two patients were male and one was female, aged 59, 45 and 35 years, respectively. In all three patients a thyroid mass was present. FNAC smears in all cases showed cytological features of squamous cell carcinoma including keratinization and necrosis. After clinical and cytological correlation, one case appeared to be primary, one case metastatic, and in the third case no additional clinical information or biopsy follow‐up was available for further characterization. Conclusions: Because primary squamous cell carcinoma of the thyroid is a rare finding, metastatic squamous cell carcinoma should always be excluded first. Metastatic disease usually presents in the setting of widespread malignancy, therefore a dedicated clinical and radiological investigation is necessary in these cases. In both clinical scenarios the patient’s prognosis is poor.     

Solitary thyroid metastasis from clear-cell renal carcinoma.

A 58-year-old woman underwent nephrectomy because of clear-cell renal carcinoma. Seven years later a solitary thyroid metastasis was detected. She is alive and well 17 months after thyroidectomy. The rarity of this manifestation is well known but its explanation is not clear. The long metastasis-free interval, a characteristic shared by other hormonally dependent neoplasms, has been explained in part by the concept of "dormant cells", which do not undergo division. The stimulus that provokes these cells into division is at present not known.     

Medullary Thyroid Carcinoma Manifesting as an Ovarian Mass: Case Report and Review of Literature

ObjectiveTo report the uncommon case of a woman with abdominal pain and a complex adnexal mass, who was subsequently found to have medullary thyroid carcinoma (MTC) metastatic to the ovary.MethodsWe present the clinical history, physical findings, laboratory and imaging studies, and pathologic findings in a woman with metastatic MTC and locally aggressive disease. The genetic associations, variable clinical course, and histopathologic findings in MTC are reviewed.ResultsA 38-year-old woman with abdominal and pelvic pain underwent a computed tomographic scan of the abdomen, which showed a complex left adnexal mass. After laparoscopic left oophorectomy, histopathologic analysis of the resected ovary suggested the presence of a metastatic neuroendocrine tumor. The patient recovered but was referred to the surgery clinic 3 months later because of hoarseness, a left neck mass, and left-sided vocal cord paralysis. Further work-up was suggestive of MTC, which prompted RET testing for multiple endocrine neoplasia. The patient underwent left thyroid lobectomy and selective lymph node dissection but later required tracheostomy because of tumoral invasion of the trachea, laser debulking of the tumor, and external beam radiation therapy. One year postoperatively, development of a metastatic lesion in her right ovary necessitated a second oophorectomy.ConclusionMTC usually manifests as a solitary thyroid nodule but should be considered in patients with metastatic lesions characterized by neuroendocrine features. This unusual case highlights the biologic and clinical variability of this often aggressive thyroid cancer, which necessitates an attentive work-up, a rigorous operative strategy, and a periodic postoperative surveillance program. (Endocr Pract. 2008;14:351-357)     

What if Many Follicular Variant Papillary Thyroid Carcinomas are not Malignant? a Review of Follicular Variant Papillary Thyroid Carcinoma and a Proposal for a New Classification

ObjectivesTo review the relevant literature concerning follicular variant of papillary thyroid carcinoma (FVPTC) with an emphasis on the heterogeneity of this disorder and to propose a new classification for FVPTC on the basis of molecular diagnostics and apply the classification to a typical case.MethodsEnglish-language articles pertaining to FVPTC published between January 1990 and December 2010 were reviewed.ResultsFVPTC is particularly vexing. The criteria for diagnosing FVPTC appear to have changed over the years. Pathologists often disagree about the diagnosis of FVPTC. The clinical behavior of these tumors is variable. Molecular diagnostic studies suggest that FVPTC represents a heterogeneous group of disorders rather than a single entity.ConclusionsOn the basis of the available data, it is proposed that individual cases of FVPTC be reclassified as papillary thyroid carcinoma, follicular thyroid carcinoma, or follicular adenomas, after appropriate molecularbiologic studies have been completed. Long-term followup studies to validate this classification are necessary. (Endocr Pract. 2011;17:768-787)     

Cystic Lymph Nodes in the Lateral Neck As Indicators of Metastatic Papillary Thyroid Cancer

ObjectiveTo determine whether radiographic findings portend to metastatic disease in patients with papillary thyroid carcinoma (PTC) and whether cystic lymph node metastasis can be recognized by preoperative, ultrasound-guided fine-needle aspiration (FNA).MethodsWe performed a retrospective review of patients with cystic lymph nodes in the lateral neck identified on preoperative ultrasonography between March 1996 and December 2009. Factors examined included demographic information; stage; cytologic and final pathologic findings; and imaging characteristics including location, size, and presence of vascularity and calcifications. Time of cystic node identification in relationship to initial diagnosis was also recorded.ResultsThirty patients had cystic lymph nodes in the lateral neck on cervical ultrasonography during the study period. Among this group, 28 (93%) had PTC, 1 (3%) had papillary serous carcinoma of the ovary, and 1 (3%) had poorly differentiated thyroid cancer. Median age at initial cancer diagnosis was 41 years (range, 16-64 years). Twenty-one patients (70%) were women, and median lymph node size was 1.8 cm (range, 0.6-4.8 cm). Twenty-three patients (77%) had a solitary cystic lymph node, and the remainder had more than 1 cystic lymph node. Cystic lymph nodes were identified at initial presentation in 11 patients (37%), while cystic lymph nodes were discovered in 19 patients (63%) after the initial operation. FNA was performed on the cystic lymph nodes of 23 patients (77%). Cytologic findings were positive for metastatic disease in 18 of 23 patients (78%). Among the 5 of 23 patients with negative cytologic findings, thyroglobulin aspirate was obtained in 1 patient, confirming metastatic PTC. Final pathologic review after surgical resection of cystic lymph nodes with negative cytologic findings from FNA was consistent with metastatic disease in 4 of 5 patients (80%).ConclusionsIn patients with PTC, the presence of a cystic lymph node by ultrasonographic examination is highly suggestive of locally metastatic disease. Confirmation of metastatic PTC may sometimes be achieved with thyroglobulin aspirate from cystic lymph nodes when cytologic findings are negative. Clinicians should strongly consider surgical lymph node resection of cystic lymph nodes regardless of the preoperative cytologic findings by FNA. (Endocr Pract. 2011;17:240-244)     

Hyalinizing trabecular tumor in a background of lymphocytic thyroiditis: a challenging neoplasm of the thyroid

ObjectiveTo describe a case of hyalinizing trabecular tumor (HTT) in a background of lymphocytic thyroiditis that was misdiagnosed as papillary thyroid carcinoma (PTC) based on fine-needle aspiration (FNA) cytologic findings and overtreated with total thyroidectomy.MethodsWe present a case report, including the imaging and pathologic findings, of a 68-year-old woman who presented with a multinodular goiter that was suspicious for PTC.ResultsOn the basis of FNA cytologic findings, she underwent a total thyroidectomy, and histologic examination of the thyroid gland revealed HTT in a background of lymphocytic thyroiditis. Radioiodine treatment was not administered because of the tumor’s low risk profile. No metastatic foci were established under nonsuppressive levothyroxine therapy after 3 years of follow-up.ConclusionsHTT is a challenging entity because of the uncertainty of its nature, the diagnostic challenges,and the mimicry of other types of thyroid tumors. In order to avoid overtreatment, endocrinologists and thyroid surgeons should be aware of the features of HTT, and suspicious cases should be evaluated by experienced cytopathologists. (Endocr Pract. 2011;17:e140-e143)     

Intraoperative Diagnostic Strategy to Distinguish Parathyroid Adenomas from Metastatic Thyroid Cancer

ObjectiveTo report the limitations of frozen section examination and the value of intraoperative tissue aspiration for parathyroid hormone assay to distinguish parathyroid adenomas from metastatic thyroid carcinoma.MethodsWe describe 2 patients with a biochemical diagnosis of primary hyperparathyroidism who underwent intraoperative frozen section analysis of suspected parathyroid tumors. Parathyroid gland aspiration for parathyroid hormone was also performed for confirmation.ResultsThe intraoperative frozen section examination of the suspected parathyroid tumors inaccurately identified the tumors as follicular carcinomas. The parathyroid gland aspirate, however, accurately substantiated the presence of parathyroid adenomas, rather than follicular cancers.ConclusionAspiration of a suspected parathyroid tumor for parathyroid hormone assay accurately determines whether a nodule is a parathyroid gland and facilitates intraoperative decision making, especially when frozen section diagnosis is misleading. (Endocr Pract. 2009; 15:454-457)     

Unusual Initial Manifestation of Metastatic Follicular Carcinoma of the Thyroid with Thyrotoxicosis Diagnosed by Technetium Tc 99m Pertechnetate Scan: Case Report and Review of Literature

ObjectiveTo report a case of metastatic thyroid cancer diagnosed on a technetium Tc 99m pertechnetate (TcO₄^–) thyroid scan.MethodsWe present the clinical findings, laboratory results, imaging studies, and surgical pathology report in a man with thyrotoxicosis in whom metastatic well-differentiated thyroid cancer was diagnosed incidentally on a routine TcO₄ ^– thyroid scan in the setting of a presumed diagnosis of benign toxic thyroid disease. In addition, we review the literature regarding coexistence of metastatic thyroid cancer and thyrotoxicosis.ResultsA 68-year-old man with thyrotoxicosis was referred for radioiodine therapy. A routine TcO₄^- thyroid scan revealed high-grade extrathyroidal uptake in the right upper hemithorax as well as in the left side of the thorax. In view of this finding, radioiodine treatment was deferred; further imaging with computed tomography revealed a 6.5-cm mass in a rib on the right side. A biopsy of the rib confirmed the presence of metastatic follicular carcinoma of the thyroid. Scintigraphy revealed sites of metastatic involvement predominantly in the bones along with a cold nodule in the left thyroid lobe, consistent with the primary tumor.ConclusionThis case emphasizes the impact of scintigraphic findings on determining the correct management of a patient who would have otherwise undergone inappropriate treatment. Through an extensive literature review, the incidence of malignant involvement in hyperfunctioning thyroid glands and the possible role of sodium iodide symporter expression by thyroid cancer metastatic lesions in preoperative detection of metastatic sites are addressed. (Endocr Pract. 2009;15:458-462)