Adebowale J. Adeniran

Thyroid follicular lesion of undetermined significance: Evaluation of the risk of malignancy using the two-tier sub-classification

The Bethesda 2007 Thyroid Cytology Classification defines follicular lesion of undetermined significance as a heterogeneous category of cases that are not convincingly benign nor sufficiently atypical for a diagnosis of follicular neoplasm or suspicious for malignancy. In our institution, we refer to these cases as indeterminate, and they are further sub‐classified into two: (1) low cellularity with predominant microfollicular architecture and absence of colloid (INa) and (2) nuclear features not characteristic of benign lesions (nuclear atypia) (INb). We reviewed these indeterminate cases to document the follow‐up trend using this two‐tier classification. A search of the cytology records was performed for the period between January 2008 and June 2009. All thyroid fine‐needle aspiration (FNA) cases were reviewed and the ones diagnosed as indeterminate were identified. Correlating follow‐up FNA and/or surgical pathology reports were reviewed. The percentage of cases showing a malignancy was calculated. One hundred and seventy‐one indeterminate cases were identified, representing 2.8% of the 6,205 thyroid FNA cases examined during the time under review (107 INa, 64 INb). Records of follow‐up procedures were available in 106 (61%) cases. Malignancy was identified in 27% of all indeterminate cases. This was disproportionately more in the INb (56%) compared to the INa (7%) cases. A diagnosis of “INa” does not carry the same implication as that of “INb”. The INb category needs a more aggressive follow‐up than the INa category and may justify an immediate referral for lobectomy. Despite the vague morphologic criteria for this diagnostic category, the indeterminate rate remains relatively low and falls within the NCI recommendation (<7%). Diagn. Cytopathol. 2011;.

Reflex BRAF Testing in Thyroid Fine-Needle Aspiration Biopsy with Equivocal and Positive Interpretation: A Prospective Study

BACKGROUND The BRAF V600E mutation has been reported in 50%-80% of papillary thyroid carcinoma (PTC) cases and is highly specific for PTC. Reflex BRAF testing may improve the diagnostic accuracy of thyroid fine-needle aspiration (FNA) tests having equivocal cytologic interpretations and provide prognostic information that helps guide management in patients with PTC. PATIENTS AND METHODS Cases with equivocal thyroid FNA readings (indeterminate and suspicious for PTC) or a positive diagnosis for PTC and concomitant BRAF mutation analysis were included in this prospective study. BRAF mutation analysis was performed by polymerase chain reaction combined with single-strand conformation polymorphism gel electrophoresis using lavage fluid obtained from needle rinsing. The results of histopathologic follow-up were correlated with the cytologic interpretations and BRAF status. RESULTS One hundred fifty-seven FNAs with equivocal or positive cytologic interpretations were eligible for the study. All but one (99.4%) FNAs were found to have sufficient DNA quality and quantity for the assay. Based on the follow-up diagnosis of nodules after surgical resection, the sensitivity for diagnosing PTC was 63.3% with cytology alone and 80.0% with the combination of cytology and BRAF testing, respectively. No false positives were noted with either cytology or BRAF mutation analysis. All PTCs with extrathyroidal extension and of tall-cell variant were postive for BRAF mutation. CONCLUSIONS BRAF V600E mutation analysis can be easily performed on cytologic preparation using lavage fluids obtained from needle rinsing. By combining morphologic evaluation and BRAF testing, there is a substantial improvement in the preoperative identification of PTC when compared with cytology alone. Patients with equivocal cytologic diagnosis and BRAF V600E mutation are candidates for total thyroidectomy ± central lymph node dissection.

BRAF Mutation Testing of Thyroid Fine-Needle Aspiration Specimens Enhances the Predictability of Malignancy in Thyroid Follicular Lesions of Undetermined Significance

Background/Objective: The Bethesda 2007 Thyroid Cytology Classification defines atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) as a heterogeneous category of cases that are neither convincingly benign nor sufficiently atypical for a diagnosis of follicular neoplasm or suspicious for malignancy. At our institution, we refer to these cases as ‘indeterminate’ and they are further subclassified into two categories. BRAF mutation occurs in 40–60% of papillary thyroid carcinoma (PTC). In this study, we examined cases in the AUS/FLUS category in correlation with BRAF mutation analysis and surgical pathology outcome. Study Design: Thyroid fine-needle aspiration (FNA) cytology specimens interpreted as ‘indeterminate’ were selected from our files, and available remnants of thin-layer processed specimens were used for BRAF mutation analysis. Surgical pathology reports were reviewed for the final outcomes in these patients. Results: Of the 84 indeterminate cases with BRAF mutation analysis, only 49 had follow-up with surgical intervention. Sixteen cases had BRAF mutation. All of the BRAF-positive cases had a final diagnosis of PTC. Conclusions: The sensitivity and specificity of BRAF mutation in detecting PTC in FNA specimens with indeterminate diagnosis was 59.3 and 100%, respectively, while the positive and negative predictive values were 100 and 65.6%, respectively. The limited data supports the use of BRAF mutation analysis to predict the risk of malignancy in patients with indeterminate thyroid FNAs.

Genomic characterization of sarcomatoid transformation in clear cell renal cell carcinoma

Significance Parts of clear cell renal cell carcinomas (ccRCCs) sometimes have histologic features characteristic of a sarcoma. So-called sarcomatoid tumors are more aggressive, difficult to treat, and associated with a poor prognosis. Their pathogenesis has been uncertain. Through separate exome sequencing of carcinomatous and sarcomatoid components, we show that these components share many somatic mutations, including many in genes characteristic of ccRCC. Sarcomatoid elements had significantly more new somatic mutations, particularly in cancer driver genes, than carcinomatous components. In particular, tumor protein p53, AT-rich interaction domain 1A, and BRCA1 associated protein 1 had sarcomatoid-specific homozygous mutation in 10 tumors and were all mutually exclusive, implicating these genes in sarcomatoid degeneration. The presence of sarcomatoid features in clear cell renal cell carcinoma (ccRCC) confers a poor prognosis and is of unknown pathogenesis. We performed exome sequencing of matched normal-carcinomatous-sarcomatoid specimens from 21 subjects. Two tumors had hypermutation consistent with mismatch repair deficiency. In the remainder, sarcomatoid and carcinomatous elements shared 42% of somatic single-nucleotide variants (SSNVs). Sarcomatoid elements had a higher overall SSNV burden (mean 90 vs. 63 SSNVs, P = 4.0 × 10−4), increased frequency of nonsynonymous SSNVs in Pan-Cancer genes (mean 1.4 vs. 0.26, P = 0.002), and increased frequency of loss of heterozygosity (LOH) across the genome (median 913 vs. 460 Mb in LOH, P < 0.05), with significant recurrent LOH on chromosomes 1p, 9, 10, 14, 17p, 18, and 22. The most frequent SSNVs shared by carcinomatous and sarcomatoid elements were in known ccRCC genes including von Hippel–Lindau tumor suppressor (VHL), polybromo 1 (PBRM1), SET domain containing 2 (SETD2), phosphatase and tensin homolog (PTEN). Most interestingly, sarcomatoid elements acquired biallelic tumor protein p53 (TP53) mutations in 32% of tumors (P = 5.47 × 10−17); TP53 mutations were absent in carcinomatous elements in nonhypermutated tumors and rare in previously studied ccRCCs. Mutations in known cancer drivers AT-rich interaction domain 1A (ARID1A) and BRCA1 associated protein 1 (BAP1) were significantly mutated in sarcomatoid elements and were mutually exclusive with TP53 and each other. These findings provide evidence that sarcomatoid elements arise from dedifferentiation of carcinomatous ccRCCs and implicate specific genes in this process. These findings have implications for the treatment of patients with these poor-prognosis cancers.

Primary Diffuse Large B-Cell Lymphoma of the Testis

In this short review, we discuss primary diffuse large B-cell lymphoma of the testis, an entity that is most commonly seen in older patients. The most common clinical presentation is a unilateral testicular mass. Microscopically, the tumor shows diffuse infiltration of lymphocytes between intact seminiferous tubules. Spermatogenic arrest, interstitial fibrosis, and tubular hyalinization are commonly seen. The tumor is positive for B-cell markers by immunohistochemistry. Treatment has traditionally been with orchiectomy and combination chemotherapy; however, only a minority of patients enjoy a prolonged disease-free survival. Differential diagnosis includes seminoma and viral and granulomatous orchitis.

Endoscopic ultrasound-guided fine-needle aspiration diagnosis of Merkel cell carcinoma metastatic to the pancreas.

Merkel cell carcinoma (MCC) is a rare and highly aggressive primary neuroendocrine carcinoma of the skin with a high propensity for local, regional, and distant spread. Distant metastasis of MCC to the pancreas is uncommonly seen and may impose a diagnostic challenge cytologically. Here we report a case of MCC with pancreatic metastasis, which was diagnosed by endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA). The aspirates revealed both single and clustered epithelial cells with scant cytoplasm and round nuclei with stippled chromatin and inconspicuous nucleoli. Immunocytochemically, the tumor cells were positive for CK20, synaptophysin, CD56, and CD117. The neoplastic cells were also identified by flow cytometry as non‐hematopoietic cells which were positive for CD56 and negative for CD45. To our knowledge, this is only the second case report of MCC metastatic to the pancreas diagnosed by EUS‐FNA. There have been several reports of MCC metastatic to the pancreas diagnosed only at the time of surgical resection. However, a preoperative diagnosis allows for appropriate management while sparing a patient the morbidity of unnecessary procedures. Diagn. Cytopathol. 2014;247–252.

Tall Cell Variant of Papillary Thyroid Microcarcinoma: Clinicopathologic Features with BRAFV600E Mutational Analysis

BACKGROUND The tall cell variant of papillary thyroid carcinoma is an aggressive subtype that generally presents as a large tumor in the advanced stage; however, little is known about the tall cell variant of microcarcinoma (tumors measuring <1 cm). In this study, we compare the tall cell variant of microcarcinoma (microTCV) with classic papillary microcarcinomas to examine the hypothesis that, despite the small size, the microTCV may be more aggressive than the classic papillary microcarcinoma. METHODS We identified 27 microTCV patients and compared their clinicopathologic features and BRAF(V600E) mutational status with classic papillary microcarcinomas matched by age and size. The patients with microTCV included 22 women and 5 men aged 33 to 74 years (median age, 56 years). All patients underwent total thyroidectomy; 20 patients had lymph node dissection. RESULTS Tumor size in microTCV patients ranged from 2 mm to 10 mm (median, 7 mm). Extrathyroidal extension and lymphovascular invasion were seen in 9 (33%) and 4 (15%) tumors, respectively. Thirteen patients (48%) harbored multifocal papillary carcinomas. Metastasis to central compartment lymph nodes was seen in 8 patients and to lateral cervical nodes in 3 patients. Nine of the 25 patients (36%) presented at an advanced stage (stage III/IVA). The BRAF(V600E) mutation was detected in 25 of 27 tumors (92.6%). In contrast, age- and size-matched classic papillary microcarcinomas (n=26) showed no extrathyroidal extension (p=0.002), lymphovascular invasion in 1, central compartment lymph node metastasis in 2, lateral cervical node metastasis in 1, multifocal tumors in 10 (38.5%), the BRAF(V600E) mutation in 20 (76.9%), and it infrequently presented in stage III/IVA (7.7%, p=0.02). CONCLUSIONS The microTCV form is associated with aggressive features at presentation, and it should be differentiated from other papillary thyroid microcarcinomas.

PD-L1 Studies Across Tumor Types, its Differential Expression and Predictive Value in Patients Treated with Immune Checkpoint Inhibitors

Purpose: With recent approval of inhibitors of PD-1 in melanoma, non–small cell lung cancer (NSCLC) and renal cell carcinoma, extensive efforts are under way to develop biomarkers predictive of response. PD-L1 expression has been most widely studied, and is more predictive in NSCLC than renal cell carcinoma or melanoma. We therefore studied differences in expression patterns across tumor types. Experimental Design: We used tissue microarrays with tumors from NSCLC, renal cell carcinoma, or melanoma and a panel of cell lines to study differences between tumor types. Predictive studies were conducted on samples from 65 melanoma patients treated with PD-1 inhibitors alone or with CTLA-4 inhibitors, characterized for outcome. PD-L1 expression was studied by quantitative immunofluorescence using two well-validated antibodies. Results: PD-L1 expression was higher in NSCLC specimens than renal cell carcinoma, and lowest in melanoma (P = 0.001), and this finding was confirmed in a panel of cell lines. In melanoma tumors, PD-L1 was expressed either on tumor cells or immune-infiltrating cells. The association between PD-L1 expression in immune-infiltrating cells and progression-free or overall-survival in melanoma patients treated with ipilimumab and nivolumab was stronger than PD-L1 expression in tumor cells, and remained significant on multivariable analysis. Conclusions: PD-L1 expression in melanoma tumor cells is lower than NSCLC or renal cell carcinoma cells. The higher response rate in melanoma patients treated with PD-1 inhibitors is likely related to PD-L1 in tumor-associated inflammatory cells. Further studies are warranted to validate the predictive role of inflammatory cell PD-L1 expression in melanoma and determine its biological significance. Clin Cancer Res; 23(15); 4270–9. ©2017 AACR.

Hereditary Renal Cell Carcinoma Syndromes: Clinical, Pathologic, and Genetic Features.

Renal cell carcinomas associated with syndromes of a heritable nature account for about 4% of all renal cell carcinomas. They are characterized by an earlier age of onset, and are often multicentric and bilateral. Some of these patients may fit into well-characterized kidney cancer syndromes, while many more may have a genetic component that is not fully recognized or understood. The presence of extrarenal clinical features may suggest a specific renal tumor susceptibility syndrome. Moreover, each syndrome is associated with specific renal pathology findings. Recognition of individuals and families with a high risk of renal neoplasia is important so that surveillance for renal tumors may be initiated. This manuscript reviews the clinical, pathological, and molecular features of hereditary renal cell carcinoma syndromes with emphasis on the morphologic features of these tumors and the molecular mechanisms of hereditary renal tumorigenesis.

Risk stratification in follicular neoplasm: A cytological assessment using the modified bethesda classification

The 2007 Bethesda classification for thyroid cytology defines follicular neoplasm as a category of cases with cellular specimens demonstrating abundant follicular cells arranged in a microfollicular pattern with little or no colloid. The current recommendation for the management of these cases is diagnostic lobectomy. There has been great difficulty and variability in triaging and reporting follicular neoplasm. To increase diagnostic accuracy, at the study institution, this category is subclassified further into 3 categories: 1) microfollicular‐patterned neoplasm (MN); 2) Hürthle cell neoplasm (HN); and 3) follicular lesion with some features suggestive of but not diagnostic of the follicular variant of papillary thyroid carcinoma (FL). The authors reviewed the cases of follicular neoplasm observed over a period of 5 years to document the follow‐up trend using this modified classification.