Primary high-grade non-anaplastic thyroid carcinoma: a retrospective study of 364 cases

AIMS

We aimed to study the clinicopathological and molecular features of high-grade non-anaplastic thyroid carcinomas (HGTCs), a carcinoma with a prognosis intermediate between those of well-differentiated carcinoma and anaplastic carcinoma.

METHODS AND RESULTS

This study included 364 HGTC patients: 200 patients (54.9%) were diagnosed with poorly differentiated thyroid carcinoma (PDTC), based on the Turin consensus (HGTC-PDTC), and 164 were diagnosed with high-grade features that did not meet the Turin criteria (HGTC-nonPDTC). HGTCs are aggressive: the 3-year, 5-year, 10-year and 20-year disease-specific survival (DSS) rates were 89%, 76%, 60%, and 35%, respectively. Although DSS was similar between HGTC-PDTC and HGTC-nonPDTC patients, HGTC-PDTC was associated with higher rate of radioactive iodine avidity, a higher frequency of RAS mutations, a lower frequency of BRAF V600E mutations and a higher propensity for distant metastasis (DM) than HGTC-nonPDTC. Independent clinicopathological markers of worse outcome were: older age, male sex, extensive necrosis and lack of encapsulation for DSS; older age, male sex and vascular invasion for DM-free survival; and older age, necrosis, positive margins and lymph node metastasis for locoregional recurrence-free survival. The frequencies of BRAF, RAS, TERT, TP53 and PTEN alterations were 28%, 40%, 55%, 11%, and 10%, respectively. TP53, PTEN and TERT were independent molecular markers associated with an unfavourable outcome, independently of clinicopathological parameters. The coexistence of BRAF V600E and TERT promoter mutation increased the risk of DM.

CONCLUSIONS

The above data support the classification of HGTC as a single group with two distinct subtypes based on tumour differentiation: HGTC-PDTC and HGTC-nonPDTC.

Histologic evaluation of host immune microenvironment and its prognostic significance in oral tongue squamous cell carcinoma: a comparative study on lymphocytic host response (LHR) and tumor infiltrating lymphocytes (TILs)

BACKGROUND

Host immune microenvironment is a key component of anti-tumoral immune response, influencing tumor progression, regression, and treatment responses. There is a need for simple and reliable histologic measurements of host immune response in routine histopathologic diagnosis.

METHODS

The prognostic value of lymphocytic host response (LHR), a qualitative histologic grading scheme, was compared to stromal/intratumoral TIL (sTIL/iTIL) percentage, a quantitative measurement in a retrospective study of 329 patients with oral tongue squamous cell carcinoma (OTSCC) of 4 cm or less in size.

RESULTS

High sTIL predicted improved distant recurrence free survival on univariate survival analysis and was an independent prognostic factor for better overall survival on multivariate analysis. LHR and iTIL were not associated with the risk of nodal metastasis or outcome.

CONCLUSIONS

sTIL appears to be a superior quantitative histologic measurement for the host immune microenvironment compared with the qualitative LHR grading scheme. sTIL is an independent prognostic factor for overall survival in OTSCC.

Diagnostic discrepancy in second opinion reviews of primary epithelial neoplasms involving salivary gland: An 11-year experience from a tertiary referral center focusing on useful pathologic approaches and potential clinical impacts

AIMS

In the era of precision medicine, accurate pathologic diagnoses are crucial for appropriate management.

METHODS

We herein described the histologic features and clinical impacts of 66 salivary gland epithelial neoplasms in which the diagnosis was altered after expert review.

RESULTS

The most common revised diagnosis was that of salivary duct carcinoma (SDC, n = 12), adenoid cystic carcinoma (n = 12), and myoepithelial carcinoma (n = 10). The most common initial diagnosis was mucoepidermoid carcinoma (n = 19) with SDC being the most common revised diagnosis (7/19). Thirteen salivary gland carcinomas were initially diagnosed as benign entities, whereas five benign tumors were initially interpreted as carcinoma. The change in diagnosis was considered to be clinically significant in 65 (97%) cases.

CONCLUSIONS

Given their rarity, salivary gland neoplasms are prone to diagnostic inaccuracy and discrepancy. A constellation of histologic features and ancillary studies are useful in reaching the correct diagnosis, which can have significant clinical impacts.

The prognostic role of histologic grade, worst pattern of invasion, and tumor budding in early oral tongue squamous cell carcinoma: a comparative study

Major pathology guidelines often mandate stating the histologic grade as a component of the pathology report for various types of cancer. However, the prognostic value of histologic grade in head and neck squamous cell carcinoma (HNSCC) is controversial at best, and there is a need for more reliable prognostic histologic factors to better stratify and manage patients with HNSCC. In this study, we compared three relevant histopathologic features (histologic grade, worst pattern of invasion (WPOI), and tumor budding) in a large single-center retrospective cohort of early oral tongue squamous cell carcinoma (OTSCC) with tumor greatest dimension ≤ 4 cm. Only histologic grade predicted distant metastasis free survival (DMFS) on univariate analysis. Tumor budding was associated with nodal metastasis, overall survival (OS), regional recurrence-free survival (RRFS), and DMFS and was a significant predictor for nodal metastasis on the multivariable logistic regression model. WPOI 5 was associated with high frequency of nodal metastasis and shortened OS and was an independent adverse prognostic factor for OS on multivariate analysis using the Cox proportional hazards model. WPOI and tumor budding were prognostically more relevant than histologic grade. Consideration should be given to include WPOI and tumor budding in the pathology reporting of OTSCC.

Depth of invasion versus tumour thickness in early oral tongue squamous cell carcinoma: which measurement is the most practical and predictive of outcome?

AIMS

The 8th edition of the American Joint Committee on Cancer (AJCC) Staging introduced depth of invasion (DOI) into the pT category of oral cavity squamous cell carcinoma. However, we noted multiple practical obstacles in accurately measuring DOI histologically in our daily practice.

METHODS AND RESULTS

To compare the prognostic effects of DOI and tumour thickness (TT), a meticulous pathology review was conducted in a retrospective cohort of 293 patients with AJCC 7th edition pT1/T2 oral tongue squamous cell carcinoma. Overall survival (OS) and nodal metastasis rate at initial resection were the primary and secondary outcomes, respectively. We found that TT and DOI were highly correlated with a correlation coefficient of 0.984. The upstage rate was only 6% (18 of 293 patients) when using TT in the pT stage compared with using DOI. More importantly, DOI and TT, as well as pT stage using DOI and pT stage using TT, performed identically in predicting risk of nodal metastasis and OS.

CONCLUSIONS

We therefore propose to replace DOI, a complicated measurement with many challenges, with TT in the pT staging system.

Metastasis to the thyroid gland: a single-institution 16-year experience

AIMS

Metastasis to the thyroid gland is a rare occurrence that may pose a diagnostic challenge. In this study, we aimed to report the clinicopathological features, immunoprofile, molecular alterations and outcome of 30 patients treated at our centre from 2003 to 2019.

METHODS AND RESULTS

The most common site of the primary tumour was the kidney, followed by the lung, lower gastrointestinal tract and breast. In seven (23%) patients, the thyroid metastases were resected prior to the diagnosis of the primary tumours. Six patients (20%) had thyroid as the sole metastatic site. Three (10%) patients harboured tumour-to-tumour metastasis; 71% had a unilateral unifocal thyroid mass, which might be mistaken for a primary thyroid tumour. Among the 13 cases that were initially diagnosed at an outside hospital, four (31%) were misinterpreted as a thyroid primary. An immunohistochemical panel of thyroid follicular cell markers was most useful to differentiate primary thyroid tumours from metastasis. Molecularly, the metastasis showed alterations characteristic of the primary tumour, which may be helpful in establishing the diagnosis and primary site. Although the prognosis was poor, with a 5-year disease specific survival of 58%, a long-term cure was possible in cases with oligometastasis successfully treated with surgery.

CONCLUSIONS

Metastasis to the thyroid gland is an uncommon phenomenon, with an incidence of 0.36% in all thyroid malignancies. It may present as a solitary thyroid mass before the discovery of the primary tumour, posing a diagnostic challenge. Although the overall prognosis is poor, a subset of patients with oligometastasis can be managed surgically.