Oncocytic (Hürthle cell) tumors of the thyroid: distinct growth patterns comparedẁith clinicopathological features

Poorly differentiated oncocytic (hürthle cell) follicular carcinoma: an institutional experience

The proposed diagnostic criteria for poorly differentiated thyroid carcinoma (known as the Turin classification) were defined based on growth pattern (solid, trabecular, or insular) and high-grade morphologic features (nuclear pleomorphism, mitoses including abnormal forms, and coagulative tumor necrosis). The development of this classification specifically did not include tumors with oncocytic or Hürthle cell cytology, and only sparse literature describing poorly differentiated oncocytic carcinomas is available. In this study, we examined a cohort of 284 cases of oncocytic follicular carcinoma/Hürthle cell carcinoma (OFC/HCC) and identified 17 cases of oncocytic variant of poorly differentiated carcinoma (OV-PDTC) based on Turin criteria. Compared to minimally invasive and angioinvasive OFC/HCC, these tumors arose in older patients (range 44-88 years; average 71 years), were larger (average size 4.5 cm), and all had extensive vascular invasion (5-15 foci), and coagulative tumor necrosis and the tumor cells were arranged in a trabecular or solid growth pattern. All showed an admixture of oncocytic follicular/Hürthle cells arranged in solid and trabecular growth pattern. Aggregates of small sized cells with minimal eosinophilic cytoplasm, comprising 10-20% of the entire tumor mass were also seen in 16/17 cases. Clinical follow-up was available in 12 cases and ranged from 6 to 120 months (average 41 months). Distant metastases were seen in 10/12 (83%) patients; two had lung and one had bone metastases at the time of thyroid surgery, and four subsequently developed cervical lymph node metastases. Two patients died of disease, and ten are alive either with or free of tumor. The OV-PDTC is a distinct entity which can be identified based on Turin criteria and the presence of a distinct "small cell" component. It is frequently associated with regional recurrence and distant metastases and can lead to tumor-related demise.

CBX7 Expression in Oncocytic Thyroid Neoplastic Lesions (Hürthle Cell Adenomas and Carcinomas)

BACKGROUND

Previous analysis of CBX7 expression in a large number of thyroid adenoma and carcinoma samples revealed a progressive reduction of CBX7 levels that was well related with the malignant grade of thyroid neoplasias. Hürthle cell tumors are unusual thyroid neoplasms characterized by the presence of particular cells called oncocytes.

OBJECTIVES

In order to develop new tools for a more accurate diagnosis of Hürthle cell tumors of the thyroid, we evaluated CBX7 protein levels to verify the possible presence of an expression signature.

METHODS

CBX7 expression was evaluated by immunohistochemistry in a panel of thyroid tissue sections including normal thyroids, goiters, follicular adenomas and oncocytic lesions.

RESULTS

CBX7 expression was low or null in 68% of Hürthle adenomas, whereas it was comparable to normal thyroid tissue in Hürthle hyperplasias and follicular adenomas.

CONCLUSIONS

Reduced expression of CBX7 suggests a more aggressive identity of Hürthle adenomas with respect to non-Hürthle ones.

Poorly differentiated oncocytic thyroid carcinoma--diagnostic implications and outcome

AIMS

  Poorly differentiated thyroid carcinomas (PDTC) are an ongoing diagnostic challenge. Although the Turin consensus criteria for PDTC excluded consideration of oncocytic tumours, the World Health Organization (WHO) classification does recognise an oncocytic variant of conventional PDTC. The aims of this study were to establish whether the Turin criteria can be applied to oncocytic PDTC, and to determine if there are prognostic differences between conventional and oncocytic PDTC.

METHODS AND RESULTS

  We applied the Turin criteria to 129 thyroid carcinomas. We identified 18 oncocytic PDTC and 16 conventional PDTC. Kaplan-Meier analysis revealed a significantly worse outcome for oncocytic PDTC with regard to overall and tumour-specific survival but no difference for relapse-free survival, all of which were confirmed by multivariate analysis. There was no association of survival with gender, age or tumour stage.

CONCLUSIONS

  The Turin criteria can be applied to oncocytic PDTC and patients with this variant have a decreased survival using conventional radioiodine treatment compared to conventional PDTC and might therefore be candidates for novel treatment modalities.

Prognostic factors of recurrence in encapsulated Hurthle cell carcinoma of the thyroid gland: a clinicopathologic study of 50 cases

BACKGROUND

Follicular carcinomas of the thyroid gland, including its oncocytic variant (so-called Hurthle cell carcinoma), are subdivided into the indolent encapsulated ("minimally invasive") and the clinically aggressive widely invasive tumors. There are, however, cases of encapsulated follicular carcinoma that recur and metastasize. Identifying these cases at the time of diagnosis is crucial for prognostic and therapeutic considerations. Because to the authors' knowledge most studies do not focus exclusively on the encapsulated Hurthle cell carcinoma (EHC), the current study attempted to identify predictors of recurrence in EHC.

METHODS

A tumor was defined as EHC if it was encapsulated, macroscopically well defined with microscopic but no macroscopic evidence of vascular or capsular invasion, and composed of > 75% follicular oncocytic cells. Retrospective chart review and microscopic examination identified 50 primary tumors meeting the above criteria at the Memorial Sloan-Kettering Cancer Center between 1967 and 2005. The cases were analyzed for various histologic and clinical parameters. Each parameter was correlated with recurrence-free survival (RFS).

RESULTS

Seven of 50 (14%) patients developed disease recurrence. All patients who developed recurrence were found to have a high number of foci of vascular invasion (> or = 4). In univariate analysis, > or = 4 foci of vascular invasion (P <.0001), tumor size > 4 cm (P = .049), the presence of mitosis (P = .018), and a solid/trabecular growth pattern (P = .009) were found to be correlated with a decreased RFS. Extensive capsular invasion, gender, and age did not confer a statistically higher recurrence rate. The finding of a solid/trabecular growth and mitosis correlated with the presence of numerous foci (> or = 4) of vascular invasion (P = .01 and P = .005, respectively).

CONCLUSIONS

A diligent search for vascular invasion is recommended in EHC that display mitosis or a solid/trabecular growth pattern. The presence of > or = 4 foci of vascular invasion should alert the pathologist and the clinician to a significantly higher risk of recurrence in EHC.

Cluster analysis of p53 and Ki67 expression, apoptosis, alpha-fetoprotein, and human chorionic gonadotrophin indicates a favorable prognostic subgroup within the embryonal carcinoma germ cell tumor

PURPOSE

The prognostic information provided by alpha-fetoprotein and human chorionic gonadotrophin in the management of germ cell tumor (GCT) patients is a biochemical reflection of tumor differentiation. Ki67, p53, and apoptosis have been found to be related to proliferation (Ki67), cell death (p53, apoptosis), and possibly differentiation chemoresistance (p53). We sought to determine whether simultaneous expression of one or more of these markers could identify clinically relevant subgroups of patients with nonseminomatous GCT (NSGCT).

PATIENTS AND METHODS

These five marker values were obtained for 95 previously untreated patients with embryonal carcinoma with or without other germ cell components. A multivariate cluster analysis was performed to identify patients with similar marker patterns.

RESULTS

One prominent cluster (n = 37; 36 testis retroperitoneum), consisting of 26 (70%) good-risk (GR), nine (24%) intermediate-risk (IR), and two (6%) poor-risk (PR) patients, as defined by the International Germ Cell Consensus Cancer Group (IGCCCG), was observed. The 5-year survival of the prominent cluster (with 30% IR/PR patients) was 94% (95% confidence interval [CI], 86% to 100%), which is comparable to the 91% (95% CI, 89% to 93%) 5-year survival of the IGCCCG GR patients. IGCCCG risk status (P =.005) and cluster affiliation (P =.04) were independent predictors of outcome with hazard ratios of 5.0 (95% CI, 1.6 to 15.4) and 4.6 (95% CI, 1.04 to 20.1), respectively.

CONCLUSION

These results suggest that there is a subgroup of NSGCT patients with embryonal carcinoma (with or without other histologies) with a specific tumor biology profile (high Ki67, low apoptosis, and low p53) whose survival is better than that of the overall patient group. The unexpectedly good outcome for the prominent cluster and independent-risk status suggest that subgroups of GCT reflecting different abilities to respond to treatment exist within IGCCCG prognostic categories.

Extensive DNA fragmentation in oxyphilic cell lesions of the thyroid

The in situ end-labeling (ISEL) method demonstrates DNA fragmentation, commonly regarded as a marker of apoptosis. We investigated by the ISEL procedure a series of 52 thyroid lesions, including 24 lesions of mitochondrion-rich oxyphilic cells, both benign and malignant, and 28 non-oxyphilic control tumors. A high percentage of nuclear ISEL staining (approximating to 100% in most cases) was observed in the vast majority of oxyphilic cells from both adenomas and carcinomas, in the absence of morphological apoptotic changes and with no immunocytochemical evidence of caspase activation. This pattern of DNA fragmentation was not observed in non-oxyphilic lesions and was confirmed in total extracted DNA. Moreover, a peculiar cytoplasmic staining was also observed in oxyphilic cells from both benign and malignant lesions, probably related to abnormal fragmentation of mitochondrial DNA. Similar staining patterns were detected in oxyphilic cell tumors of other organs (parathyroids, salivary glands, and kidneys). These findings are consistent with an extensive DNA fragmentation peculiar to oxyphilic cells, which is not directly related to apoptosis and whose origin and biological significance are presently unknown.