Oncocytoma Research Articles

What is hiding behind S100 protein and SOX10 positive oncocytomas? Oncocytic pleomorphic adenoma and myoepithelioma with novel gene fusions in a subset of cases

Oncocytomas (OCs) in salivary glands are rare benign tumors composed of mitochondria-rich epithelial cells (oncocytes), mostly localized in the parotid gland. The treatment of choice is simple excision. Extensive oncocytic metaplasia of pleomorphic adenoma (PA) and myoepithelioma (ME) can be diagnostically challenging and may camouflage the correct diagnosis. These tumors should be treated more carefully compared with OC, given the risk of frequent recurrences and the possibility of malignant transformation. We have investigated 89 oncocytic lesions from our files, including OC (n=74) and metaplastic oncocytic variant of PA/ME (n=15). All OCs were stained for S100 protein and SOX10. The tumors with immunohistochemical expression of one or both markers were tested by next-generation sequencing (NGS). The NGS results were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH). Ten cases originally diagnosed as OC, and 1 low-grade uncertain oncocytic tumor (11/74) revealed nuclear-cytoplasmic and/or nuclear positivity for S100 protein and/or SOX10, respectively. Fusion transcripts CHCHD7-PLAG1 and GEM-PLAG1 were found in 2 cases (1 fusion in each), and these were confirmed by RT-PCR and PLAG1 break-apart FISH probe, respectively. Another 5 cases were positive for PLAG1 rearrangement by FISH. In the control group of 15 oncocytic PA/ME, 4/15 tested tumors harbored gene fusions including NFT3-PLAG1, CHCHD7-PLAG1, FBXO32-PLAG1, and C1orf116-PLAG1 (1 fusion in each case) as detected by NGS. Two fusions were confirmed by RT-PCR, 1 case by FISH, and 1 case was not analyzable by FISH. We additionally tested 24 OCs negative for S100 protein and SOX10 by immunohistochemistry (IHC) and by FISH for rearrangement of PLAG1 gene, but none of them were positive. SOX10 and/or S100 protein immunopositivity in conjunction with rearrangement of the PLAG1 gene assisted in reclassification of a subset of oncocytomas as oncocytic variants of PA and ME. Therefore, we recommend to include S100 protein and SOX10 IHC when diagnosing tumors with predominantly oncocytoma-like differentiation. In addition, by NGS, 3 new gene fusions were detected in oncocytic ME, including NTF3-PLAG1, FBXO32-PLAG1, and GEM-PLAG1, and a new fusion C1orf116-PLAG1 was detected in oncocytic PA.

A Rarity, Oncocytoma of the Eyelid

A Rarity, Oncocytoma of the Eyelid

Oncocytic Variant of Adrenocortical Carcinoma: Case Report of a Rare Malignancy

Adrenocortical carcinoma is a rare cancer. Oncocytic tumors of the adrenal gland are rarer. Most Oncocytic Adrenal Neoplasms are benign and carry favourable prognosis. They are classified as oncocytoma, oncocytic neoplasm of uncertain malignant potential and oncocytic adrenal carcinoma. The malignant nature of oncocytic neoplasm of adrenal gland can only be confirmed on histopathology. We report a case of a 55-year-old male with newly diagnosed hypertension being evaluated for left adrenal mass concerning for adrenocortical carcinoma. Open radical left adrenalectomy and nephrectomy was done and histopathology confirmed oncocytic variant of adrenocortical carcinoma based on Lin-Weiss-Bisceglia scoring system which has been developed particularly for oncocytic type of tumor. Though rare, oncocytic neoplasm has to be considered as one of the differential diagnoses of adrenocortical mass, especially those presenting as a large mass because malignant oncocytic neoplasm of adrenal gland as large as 23cm have been reported. Imaging modalities like ultrasonography, computed tomography or magnetic resonance imaging, though useful in evaluating an adrenocortical mass, cannot predict malignant nature of an oncocytic neoplasm. Diagnosis of adrenocortical carcinoma is therefore reliably made only after histopathological examination of the surgical specimen. Surgical resection in those presenting with nonmetastatic resectable disease remains the mainstay of ACC treatment. Oncocytic ACC compared with conventional ACCs matched for age, gender, disease stage and status of surgical resection, shows significant better overall survival thus representing more indolent variant of an aggressive and often fatal disease.

SUN-179 Oncocytic Adrenocortical Carcinoma: A Case Report

Adrenocortical carcinoma (ACC) is a rare tumor with a poor prognosis. Oncocytic variant of adrenocortical carcinoma is considered to be an even more rare malignancy with four reported in the literature in 2002 and thirty-six documented in 2015 i ii. This case report illustrates the case of oncocytic ACC.A 40-year-old woman post-hysterectomy from cervical cancer presented to the ER with severe left flank and back pain for two weeks. There was no weight loss or early satiety. CT scan revealed a large left adrenal mass measuring 12x9x13 cm, displacing the left kidney inferiorly with no metastasis to nearby structures. We ruled out functional adrenal mass through a 24-hour urine collection and blood work, then performed open left adrenalectomy.Grossly, it was a large, tan-colored mass, weighing approximately 2,500 grams. On biopsy, we incidentally found the mass to be oncocytic adrenocortical carcinoma. Using the Lin-Weiss-Bisceglia criteria, it met two major and one minor criteria, when only one major criterion is required to indicate malignancy. Immunohistochemical stains showed that the tumor cells were positive for Mart-1, inhibin, and synaptophysin. Quantitative Ki-67 showed a proliferation index of 10% in average (>5% is considered malignant). Even though adrenocortical carcinoma, specifically the oncocytic variant of ACC, is a very rare occurrence, it should be on the differential diagnosis for a chief complaint of unilateral flank pain with a large adrenal mass on CT due to its poor prognosis.Endnotes i Hoang, M., Ayala, A. & Albores-Saavedra, J. Oncocytic Adrenocortical Carcinoma: A Morphologic, Immunohistochemical and Ultrastructural Study of Four Cases. Mod Pathol 15, 973-978 (2002) doi:10.1038/modpathol.3880638 ii Kalra S, Manikandan R, Srinivas BH. Oncocytic adrenocortical carcinoma--a rare pathological variant. BMJ Case Rep. 2015;2015:bcr2014208818. Published 2015 Apr 24. doi:10.1136/bcr-2014-208818

Clinicopathological Profile of Thyroid Carcinomas: A 10-Year Experience in a Tertiary Care Institute

Objective: Thyroid gland is an important endocrine gland and thyroid cancers (TC) are the most noteworthy disease of the thyroid gland. Although thyroid surgery is performed for most particularly for malignancy, thyroidectomies still maintain a large part of surgical operations. We aimed to investigate the incidence and subtypes of the thyroid cancers in present study, with our 10 years experience of thyroid surgery.Methods: Data of patients who underwent thyroidectomy were retrospectively analyzed. The patients who underwent bilateral total thyroidectomy were included to the study. Patients’ age, gender and histopathological results were recorded. According to the histopathological reports we divided the patients into two groups either as benign or malignant.Results: A total of 3632 patients were included in the study. 2999 (82.6%) patients were in benign group and 633(17.4%) patients were in malignant group. The subtypes of malignant tumors were papillary carcinoma in 591 (93.4%), medullary carcinoma in 16 (2.5%), follicular carcinoma in 14 (2.2%), oncocytic (hurtle cell) carcinoma in 7 (1.1%) and undifferentiated (anaplastic) in 5(0.8%) of the cases.Conclusion: Incidental thyroid cancers are not a rare entity after pathological examination of thyroid specimen after surgery. Therefore, we suggest careful evaluation and bilateral leb lobectomy ectomy in surgical treatment of thyroid conditions

Aberrant Expression of Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) in Warthin Tumors

The Warthin tumor represents the second most frequent benign tumor of the parotid gland and is characterized by the presence of oncocytes rich in structurally and functionally altered mitochondria. Next to its role in metabolism, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is also implicated in cellular mitophagy. Immunohistochemistry was carried out on Warthin tumor and normal control (parotid gland with striated ducts) tissues, using anti-GAPDH specific antibodies followed by digital image analysis. Laser capture microdissection was used to isolate the oncocytic tumor cell and normal control striated duct compartments for RNA extraction and qPCR. Warthin tumor oncocytes exhibited a markedly spotted GAPDH staining pattern exhibiting cells with cytoplasmic and nuclear, only nuclear or none GAPDH staining. A significantly lower (p < 0.0001) total GAPDH signal was detected in Warthin tumor oncocytes. Similarly, significantly lower (p < 0.005) GAPDH mRNA levels were seen in oncocytes compared with normal ductal cells. To exclude the possibility of this GAPDH staining pattern being a general feature of oncocytic neoplasms of different organs, we tested a cohort of renal oncocytoma and oncocytic chromophobe carcinoma; none showed this type of staining. The observed progressive GAPDH loss in Warthin tumor oncocytes could be implicated in the pathogenesis of Warthin tumors.

RENAL CELL CARCINOMA WITH ONCOCYTIC CELL TUMOR IN ASEMPTOMATIC DIALYSIS PATIENT

Kronik böbrek yetmezlikli ve renal replasman tedavisi gören hastalarda kardiyovasküler hastalıklar (%56), infeksiyonlar (%11.2) ve maligniteye (%8) bağlı artmış mortalite oranları söz konusudur. Diyaliz süresi uzadıkça malignite görülme oranı da artar. Diyaliz hastalarında renal hücreli karsinom (RCC) prevalansının genel popülasyona göre daha yüksek olduğu bilinmektedir. Edinilmiş kistik böbrek hastalığı (ACKD) sıklığı diyaliz süresi ile artar; CKD ile ilişkili RCC erkeklerde daha sık görülür; sıklıkla bilateral ve multisentriktir. Renal hücreli tümörlerden olan onkositom varyant bir tümör olarak kabul edilmesine rağmen histopatolojik olarak malign tümör özellikleri gösterebilir. Bu yazıda uzun süreden beri hemodiyaliz tedavisi gören ve yakınması olmayan hastada rastlantısal olarak saptanan renal kitleler anlatılmaktadır.

Birt-Hogg-Dub\xe9 syndrome with simultaneous hyperplastic polyposis of the gastrointestinal tract: case report and review of the literature

BackgroundBirt-Hogg-Dubé syndrome (BHDS) is a rare autosomal dominant genodermatosis characterized by benign growth of the hair follicles, the presence of pulmonary cysts, spontaneous pneumothorax, and bilateral renal tumors that are usually hybrid oncocytic or multifocal chromophobe renal cell carcinoma. The diagnosis is confirmed by the presence of a pathogenic variant in the tumor suppressor folliculin (FLCN) gene mapped at 17p11.2. Although the dermatological lesions typical of BHDS are benign and only cause aesthetic concerns, and the pulmonary manifestations are controllable, the greater tendency of patients with this syndrome to present benign or malignant renal tumors, often bilateral and multifocal, makes the diagnosis of this syndrome important for the prognosis of the patients. The objective was to report the case of a patient with BHDS, without pulmonary manifestations and with hyperplastic polyposis of the gastrointestinal tract, and to perform a literature review.Case presentationA 60-year-old man complained of abdominal pain and diarrhoea for 2 months. Physical examination was normal except for the presence of normochromic papules in the frontal region of the face associated with hyperkeratotic and hyperchromic papules in the dorsal region. The excisional biopsies of the skin lesions indicated trichodiscomas. Esophagogastroduodenoscopy, enteroscopy, and colonoscopy showed the presence of hyperplastic polyps in the stomach, duodenum, jejunum, colon, and rectum. Computed tomography (CT) and magnetic resonance imaging (MRI) of the abdomen revealed multiple expansive solid lesions in both kidneys, with necrotic and calcified areas. Renal magnetic resonance angiography also showed a solid lesion in the right kidney measuring 5 cm in diameter and another solid lesion in the left kidney measuring 8 cm in diameter, both suggestive of renal angiomyolipoma. CT scans of the skull, chest, and temporal bones were normal. The genetic study revealed the presence of a variant of FLCN in the intron 13.ConclusionsTo the best of our knowledge, this is the first reported case of BHDS with the simultaneous finding of gastrointestinal hyperplastic polyposis, which may represent a possible phenotypic expression of this syndrome that has not yet been described.

PD-L1 and thyroid cytology: A possible diagnostic and prognostic marker.

Programmed death-ligand 1 (PD-L1) expression is emerging as an important predictive biomarker in anti-PD-L1 cancer immunotherapy. Its role has been clearly defined in various human cancers and is linked to a poor prognosis and resistance to anticancer therapies. The role of PD-L1 in thyroid cancers has not been well defined in fine-needle aspiration cytology (FNAC). The authors examined the performance of PD-L1 immunostaining in liquid-based cytology (LBC) to determine whether it could be a biomarker of malignancy or aggressive disease. From January 2018 to March 2019, 236 thyroid lesions, which had been diagnosed by FNAC as indeterminate lesions, suspicious for malignancy (SFM), and malignant, were enrolled. PD-L1 immunostaining was performed on both LBC and corresponding histology samples. The FNAC cohort included 50 benign negative controls, 42 samples of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 33 samples of follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 53 samples that were suspicious for malignancy (SFM), and 58 malignant samples. AUS/FLUS samples included 3 goiters, 32 follicular adenomas (FAs), 1 noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), 5 invasive follicular variants of papillary thyroid carcinoma (I-FVPTCs), and 1 follicular carcinoma; whereas FN/SFN samples included 24 FAs and 9 malignancies (4 I-FVPTCs, 1 NIFTP, 3 papillary thyroid carcinomas [PTCs], and 1 oncocytic follicular carcinoma). The 53 SFM samples were diagnosed on histopathology as 2 FAs, 5 NIFTPs, 15 I-FVPTCs, and 31 PTCs; whereas the 58 malignant specimens included 5 NIFTPs, 5 I-FVPTCs, and 48 PTCs. Increased plasma membrane and cytoplasmic PD-L1 expression was found in 79 cases (38.5%), including 61 PTCs (conventional and variants). Negative PD-L1 expression was found in NIFTPs and FAs. A BRAF V600E mutation was identified in 15% of PD-L1-positive malignancies. The current data suggest that PD-L1 expression in the thyroid gland might represent a marker of malignancy that correlates with PTC, but not with NIFTP. Thyroid neoplasms with PD-L1 expression also ae enriched with BRAF V600E mutations, suggesting that they are associated with more aggressive behavior.

Combined use of galectin-3 and thyroid peroxidase improves the differential diagnosis of thyroid tumors.

The differential diagnosis of well-differentiated tumors of follicular cell origin remains the most problematic task in thyroid pathology. Specific morphologic criteria (capsular and/or vascular invasion, nuclear characteristics) are crucial in the diagnosis of these neoplasms. However, the assessment of malignant features is inconclusive in some cases. Moreover, oncocytic thyroid tumors remain controversial in a respect to their pathobiology, behavior and management. Therefore, the useful diagnostic/prognostic thyroid markers are awaited. The aim of our study was to evaluate the expression of galectin-3 and thyroid peroxidase (TPO) in benign and malignant thyroid tumors of follicular cell origin. A total of 186 archival thyroid samples including 38 non-oncocytic follicular adenomas, 53 oncocytic (Hürthle cell) adenomas, 6 non-oncocytic follicular carcinomas, 23 oncocytic (Hürthle cell) carcinomas, 43 non-oncocytic papillary carcinomas, and 23 oncocytic papillary carcinomas were analyzed for galectin-3 and TPO expression by immunohistochemistry. Both types of papillary carcinomas showed significant upregulation of galectin-3 in comparison with the other tumor types, likewise, significant differences in galectin-3 expression were discovered between non-oncocytic and oncocytic variants of studied tumors excluding follicular carcinoma. Significant lowering of TPO was revealed in oncocytic adenomas and papillary carcinomas. In conclusion, the combined use of galectin-3 and TPO markers could help to improve the differential diagnosis of thyroid tumors. Differences in the galectin-3 and TPO expression between some oncocytic and non-oncocytic tumors support their separation in the latest WHO classification of thyroid tumors.

Cytologic Diagnosis of Oncocytic Neoplasms of the Thyroid Gland: The Importance of the Clinical Scenario.

It is a diagnostic challenge to differentiate benign and malignant thyroid neoplasms made up of Hürthle (or oncocytic) cells on cytologic material. They are large, polygonal cells with marked eosinophilic, granular cytoplasm reflective of overly abundant mitochondria. These cells commonly occur in nodular goiters and dominant adenomatous or hyperplastic nodules though they may also be the predominant component of neoplastic lesions. There are significant controversies concerning the optimal management of patients with oncocytic cell carcinoma. This review provides an overview of the most significant studies addressing the distinction between benign and malignant Hürthle cell lesions on cytology and histology.

Untargeted Lipidomics Reveals Specific Lipid Abnormalities in Nonfunctioning Human Pituitary Adenomas.

The pituitary gland is a small but important organ located in the base of the brain. Although mostly noncancerous, pituitary adenomas (PAs) can cause serious health problems such as headaches, visual field defects, double vision, and hypopituitarism by invasion of regional structures. Nonfunctioning PAs (NFPAs) approximately account for one-third of PAs manifested by no circulating hormone hypersecretion. Lipid reprogramming has been recognized as a hallmark of tumor cells and proven to play a crucial role in tumorigenesis. However, the lipid molecular pathogenesis of NFPAs has remained obscure to date. To uncover lipid alterations that may contribute to the development of NFPAs and define their molecular characteristics, we investigated tissue lipids of patients with NFPAs including eight null cell adenomas (NCAs) and eight oncocytomas (OCMs) and of five normal pituitary glands as the control (Ctrl) using nontargeted lipidomics based on ultrahigh-performance liquid chromatography-Orbitrap Q-Exactive HF mass spectrometry. The lipidomic results were further validated in another set of subjects consisting of 8 NCAs, 10 OCMs, and 6 Ctrls to define crucial lipids discriminating NFPAs from the normal pituitary tumors. Lipidomic analyses revealed that OCM showed more pronounced changes in lipid compositions than NCA and Ctrl. As expected, mitochondria abundant cardiolipins were remarkably increased in OCM, which was accordant with the biochemical evidence of mitochondria hyperplasia in OCM. Significantly increased levels of phospholipids (PLs), especially arachidonic acid (AA)-enriched PLs, were unique characteristics of lipid profiling in OCM vs Ctrl. Our results indicate that AA-PLs may have diagnostic potential for OCM.

A case report of renal oncocytoma and literature review

目的 探讨肾嗜酸细胞瘤的诊断和治疗。 方法 回顾性分析1例误诊为左肾细胞癌的肾嗜酸细胞瘤患者的临床资料，并查阅相关文献。 结果 该患者因腰痛检查发现左肾占位，行彩超、CT检查，提示肾恶性肿瘤，行手术治疗，术后病理确诊肾嗜酸细胞瘤。 结论 肾嗜酸细胞瘤临床罕见，其影像学表现与肾恶性肿瘤类似，易于混淆，临床医生应提高认识，拓宽诊断思路，总结经验教训，尽量避免误诊误治。

Oncocytic adrenocortical carcinoma

Oncocytic adrenocortical carcinoma is an extremely rare tumor, with only 150 cases reported in the literature. A 48-year-old male patient, with right adrenalectomy due to a 7-cm non-functional adrenal inciden- taloma. From a clinical imaging point of view, oncocytic adrenocortical carcinoma cannot be distinguished from other more common adrenal tumors; therefore, the diagnostic confirmation is histological. It is rarely malignant, and the accepted treatment is laparoscopic adrenalectomy. In our case, two minor histological criteria classify it as a potentially malignant tumor.

Clinicopathological features and outcomes after radioactive iodine treatment of oncocytic well-differentiated thyroid carcinomas.

The aim of this study was to compare the clinicopathological features of Hürthle cell carcinomas (HCC) and oncocytic papillary thyroid carcinomas (OPTC) and to evaluate their response to radioactive iodine (RAI) treatment. We retrospectively reviewed the charts of patients with histopathologically verified OPTC (group 1) and HCC (group 2), during a 17-year period. All patients underwent total thyroidectomy and received RAI adjuvant therapy. Clinicopathological characteristics of the two groups were compared. Response to initial therapy was assessed 6 to 24 months after RAI ablation according to the American Thyroid Association dynamic risk reclassification. Clinical outcomes were evaluated. A total of 28 patients (8 OPTC and 20 HCC) were included. There was no significant difference in clinicopathological features including sex, age, tumour size and vascular invasion. Distant metastases were absent in both groups. OPTC, however, presented more features of local invasion (50% vs. 10%, P = 0.03), extrathyroidal extension (25% vs. 0%, P = 0.07) and lymph node involvement (37.5% vs. 0%, P = 0.01). Median cumulative RAI activity administered to both groups was 200 mCi (range: 100-300 mCi). Response to RAI therapy was excellent in all HCC and 87.5% of OPTC (P = 0.28). One patient with OPTC (12.5%) presented an indeterminate response. Clinical outcomes were favourable after a median follow-up of 87.5 and 49 months, respectively. Although OPTC presented more locoregional invasion, clinicopathological characteristics of OPTC and HCC were comparable. Both OPTC and HCC were iodine responsive. We suggest that adjuvant RAI therapy after total thyroidectomy is beneficial for OPTC and HCC and may improve disease-free survival.

Parotid Gland Oncocytoma: A Rare Case and Literature Review

Oncocytoma is a rare salivary gland tumor consisting of oncocytes with many hyperplastic mitochondria. It usually occurs in the parotid gland. Clinical diagnosis is often challenging due to the likeness of oncocytoma to other benign and low-grade malignant salivary gland tumors. We report a case of a patient who presented to our department with a right parotid swelling evolving for 1 year. Imaging studies diagnosed the lesion as a benign tumor. The patient underwent superficial parotidectomy with complete tumor excision with no complication. Definitive histology examination concludes to oncocytoma. The patient is disease free with a follow-up of 3 years. J Med Cases. 2019;10(5):146-149 doi: https://doi.org/10.14740/jmc3288

Neurological symptoms in a patient diagnosed with adrenal oncocytic cortical carcinoma. (P1.9-041)

Neurological symptoms in a patient diagnosed with adrenal oncocytic cortical carcinoma. (P1.9-041)

Recognizing the Limitations and Pitfalls of Cytology for Anaplastic Carcinoma within Hürthle Cell (Oncocytic) Carcinomas

Fine needle aspiration is an initial method for diagnosis of enlarged thyroid nodules. Hurthle cell neoplasm is usually cytomorphologically distinct from undifferentiated/anaplastic thyroid carcinoma, except when there is marked atypia. Herein we contrast two cases, highlighting Hurthle cell atypia mimicking anaplastic change versus true anaplastic thyroid carcinoma. The first case is of a 44 year old female with a rapidly enlarging thyroid mass presenting with an outside fine needle aspiration diagnosis of anaplastic thyroid carcinoma; however the thyroidectomy found only a Hurthle cell follicular carcinoma with a component of cytologic atypia. The second case is from an 81 year old female with acute onset neck swelling. The cytologic evaluation was suspicious for a Hurthle cell neoplasm only, while the thyroidectomy showed Hurthle cell follicular carcinoma with anaplastic thyroid carcinoma. Hurthle cell neoplasm may have marked atypia, for which anaplastic thyroid carcinoma is important to exclude. Since fine needle aspirations have sampling limitations, subsequent surgical excision is essential in determining the correct diagnosis in cases of cytologic Hurthle cell neoplasm which may harbor anaplastic thyroid carcinoma.

The key radiologic and cytomorphologic features of oncocytic and oncocytoid lesions of the salivary gland.

Oncocytic and oncocytoid lesions represent a distinct subset of salivary gland lesions. True oncocytic lesions of the salivary gland are entirely composed of oncocytes. These are characterized by the presence of abundant eosinophilic granules due to the presence of abundant cytoplasmic mitochondria. Oncocytic lesions of the salivary gland include oncocytosis, oncocytoma, and oncocytic carcinoma. In addition to the true oncocytic lesion, there exists another group of salivary gland lesions, which demonstrate cells with abundant and occasionally granular cytoplasm. These are often termed as "oncocytoid" lesions. The recently proposed Milan System for reporting salivary gland cytology clearly states that fine-needle aspiration specimens representing oncocytic/oncocytoid lesions of salivary gland cannot effectively distinguish between a nonneoplastic lesion, benign and malignant neoplasms. Therefore, most lesions lacking classic cytomorphologic features will be classified under the umbrella diagnostic term of "Salivary Gland Neoplasm of Uncertain Malignant Potential" (SUMP). In this review, we discuss and illustrate key clinicopathologic and radiologic features that can help the practicing cytopathologist narrow down the differential and provide the best management based diagnosis.

Comparison of irisin hormone expression between thyroid cancer tissues and oncocytic variant cells.

Objective: The incidence of thyroid cancer has been continuously increasing. The main objective of this study was to investigate irisin expression in various thyroid pathologies and to compare these expression patterns with irisin expression in healthy thyroid tissues.Methods: The study groups consisted of 20 cases each of control thyroid tissue, Hashimoto’s thyroiditis, thyroid papillary carcinoma, oncocytic papillary carcinoma, follicular thyroid carcinoma, oncocytic follicular thyroid carcinoma, medullary thyroid carcinoma, anaplastic thyroid carcinoma. Irisin expression was evaluated using immunohistochemistry. Irisin levels in thyroid tissue supernatants were measured using ELISA.Results: Patients with HT showed increased irisin expression compared with controls (p<0.05). In addition, mild immunoreactivity was observed in the thyroid tissues of patients with papillary carcinoma while significantly increased irisin immunoreactivity was observed tissues of patients with oncocytic papillary carcinoma (p<0.05). There was no difference in irisin immunoreactivity in thyroid tissues between patients with follicular carcinoma and controls. However, irisin immunoreactivity was higher in tissues of patients with oncocytic follicular carcinoma than in tissues of patients with follicular carcinoma (p<0.05). No irisin immunoreactivity was observed in tissues of patients with medullary carcinoma, a malignant tumor the thyroid; however, irisin expression was significantly increased in tissues of patients with anaplastic carcinoma compared with that in tissues of controls (p<0.05). Furthermore, in all thyroid tissues with irisin expression, irisin immunoreactivity was observed in follicular cells, indicating that irisin is produced by these cells.Conclusion: Irisin is a novel potential immunohistochemical marker for differentiating oncocytic variants of papillary and FTCs from papillary and follicular thyroid cancers.