Imaging features and surgical management of giant parathyroid adenoma with autoinfarction

Autoinfarction of a parathyroid adenoma can have an atypical clinicoradiologic features that can mimic an inflammatory process or malignancy. In addition, the associated fibrosis makes surgical resection more challenging than for regular parathyroid adenomas. The implications of these findings are that while autoinfarction of parathyroid adenomas is a rare phenomenon, this entity should be considered when there are heterogeneous and cystic components on imaging in patients without hypercalcemia. Ultimately, histopathology is necessary for definitive diagnosis.

The Diagnostic Utility of Repeat Fine-needle Aspirations of Benign Thyroid Nodules

Objective This study aims to analyze the diagnostic utility of multiple repeat FNA on thyroid nodules with initially benign diagnosis. Methods In a 5-year period, 1658 thyroid nodules with initially benign FNAs were retrospectively reviewed and followed for subsequent resection and repeat biopsy. Results Out of 2150 thyroid nodules, 1658 (77.1%) were diagnosed as benign on FNAs. The average age was 57.4 years (range 11-93 years), and most were females (83.8%). Repeat FNA was performed on 183 benign nodules, of which 141 (8.5%) were sampled a second time and 42 (2.5%) had 2 or more repeat samplings. For the benign nodules without repeat FNAs, 124 had benign resection. Of cases with one-time repeat FNA, most (n=101) remained benign on repeat FNAs, 13 of which were benign on resection. Eleven had atypical repeat FNAs, 5 were resected, 4 of which were benign and one was atypical follicular neoplasm with HRAS and TERT promoter mutations. Of cases with multiple repeat FNA, most (n=35) were still benign on repeat FNAs, one had benign resection. Two had atypical repeat biopsies, one was PTC on resection with CCD6::RET fusion. The positive predictive value significantly decreased from 41.1% on single FNA to 8.3% on one-time repeat (p<0.001) and 16.7% on multiple repeat (p=0.002). The total cost for workup of previously benign nodules was $285,454. Conclusions Repeat FNA biopsies did not provide an additional diagnostic value in the evaluation of benign thyroid nodules, and often led to unwarranted follow-up procedures and significantly increased health care cost.

Small biopsies in the head and neck: Bone and soft tissue

Bone and soft tissue lesions in the head and neck encompass not only a broad morphologic spectrum but also significant inherent clinicopathologic overlap. Epidemiology, radiology, and location - similar to the diagnostic assessment in other sites - are especially important considerations in the context of an established mesenchymal proliferation. Herein, the approach towards diagnosis is stratified by morphology (spindle, sarcomatoid, epithelioid, round cell), cellular lineage (fibroblastic, nerve sheath, rhabdomyogenic), and tumor grade (benign, low- to high-grade malignant) as the basis of further immunohistochemical or molecular investigation.

Deep learning generates synthetic cancer histology for explainability and education

Artificial intelligence methods including deep neural networks (DNN) can provide rapid molecular classification of tumors from routine histology with accuracy that matches or exceeds human pathologists. Discerning how neural networks make their predictions remains a significant challenge, but explainability tools help provide insights into what models have learned when corresponding histologic features are poorly defined. Here, we present a method for improving explainability of DNN models using synthetic histology generated by a conditional generative adversarial network (cGAN). We show that cGANs generate high-quality synthetic histology images that can be leveraged for explaining DNN models trained to classify molecularly-subtyped tumors, exposing histologic features associated with molecular state. Fine-tuning synthetic histology through class and layer blending illustrates nuanced morphologic differences between tumor subtypes. Finally, we demonstrate the use of synthetic histology for augmenting pathologist-in-training education, showing that these intuitive visualizations can reinforce and improve understanding of histologic manifestations of tumor biology.

Top 10 Clear Cell Head and Neck Lesions to Contemplate

BACKGROUND

Optically clear cytoplasm may occur in neoplastic and non-neoplastic conditions, either as a characteristic feature of a disease entity or as a morphologic rarity, potentially creating diagnostic dilemmas in various organ systems. In the head and neck, clear cell change can occur in lesions of salivary, odontogenic, thyroid, parathyroid, or sinonasal/skull base origin, as well as in metastases to these regions.

METHODS

This review elaborates the top ten clear cell lesions in the head and neck, emphasizing their distinguishing histologic, immunohistochemical, and molecular attributes, and presents a rational approach to arriving at an accurate classification.

RESULTS

Cytoplasmic pallor or clearing may be caused by accumulations of glycogen, lipid, mucin, mucopolysaccharides, water, foreign material, hydropic organelles, or immature zymogen granules. Overlapping morphologic features may present a diagnostic challenge to the surgical pathologist. Similarity in immunohistochemical profiles, often due to common cell type, as well as rare non-neoplastic mimics, furthers the diagnostic conundrum.

CONCLUSIONS

The top ten lesions reviewed in this article are as follows: (1) clear cell carcinoma (salivary and odontogenic), (2) mucoepidermoid carcinoma, (3) myoepithelial and epithelial-myoepithelial carcinoma, (4) oncocytic salivary gland lesions, (5) squamous cell carcinoma, (6) parathyroid water clear cell adenoma, (7) metastatic renal cell carcinoma (especially in comparison to clear cell thyroid neoplasms), (8) sinonasal renal cell-like adenocarcinoma, (9) chordoma, and (10) rhinoscleroma.

To Freeze or Not to Freeze? Recommendations for Intraoperative Examination and Gross Prosection of Thyroid Glands

The use of intraoperative consultation for indeterminate thyroid lesions is not advocated but is still requested by some surgeons. Obscured cytomorphology and nonrepresentative sampling limit the specificity of intraoperative assessment. Formalin fixation of thyroid glands before sectioning also minimizes artifacts introduced by fresh sectioning. Inking of thyroid may vary based on institutional preferences and information desired by clinical teams. Sectioning may occur in the conventional transverse method or the modified transverse vertical method to more thoroughly evaluate the lesion's periphery. Gross examination of thyroid lesions should always consider possible high-grade features, such as necrosis or extrathyroidal extension.

Right Vocal Cord Paralysis Caused by Histoplasmosis: A Case Report

OBJECTIVES

Histoplasma capsulatum is a prevalent dimorphic fungus, reaching an exposure rate of 90% in endemic areas such as the Midwest and Central United States. We report an unusual presentation of dysphonia due to right vocal cord paralysis caused by mediastinal lymphadenopathy from histoplasmosis.

METHODS

A 73-year-old male presented to an otolaryngology clinic with 4 months of hoarseness. Flexible strobolaryngoscopy demonstrated right vocal cord paralysis in lateral position and a full length glottic gap. Computerized tomography (CT) scan showed enlargement of a right paratracheal node.

RESULTS

A lymph node biopsy was obtained and showed histoplasmosis. He was treated with a 3-month course of pozaconazole. He then received a vocal cord medialization injection 2 months after symptom onset, which produced favorable improvement of his symptoms at 8-month follow up.

CONCLUSIONS

One other case report in the literature has reported left vocal cord paralysis related to histoplasmosis. This first case of right vocal cord paralysis was extremely unusual and is not often included in the differential diagnosis of vocal cord paralysis.

High-Grade Non-Anaplastic Thyroid Carcinomas of Follicular Cell Origin: A Review of Poorly Differentiated and High-Grade Differentiated Carcinomas

Poorly differentiated thyroid carcinoma (PDTC) and high-grade differentiated thyroid carcinoma (HGDTC) are considered high-grade follicular-derived thyroid carcinomas, with prognoses intermediate between well-differentiated and anaplastic thyroid carcinoma. Both share the presence of invasion, thyroid follicular-cell origin, and tumor necrosis or increased mitoses (≥ 3 mitoses per 2 mm² in PDTC and ≥ 5 mitoses per 2 mm² in HGDTC), without anaplastic dedifferentiation. PDTC must possess solid, trabecular, or insular growth and lack classic papillary-like nuclei; HGDTC can be of any architectural or nuclear morphology (follicular-like, papillary-like, oncocytic). Transformation may be accompanied by acquisition of high-risk mutations (such as TP53 or TERT promoter) on top of RAS-like or BRAF p.V600E-like (including NTRK-fusion) initial driver mutations. These carcinomas most frequently affect adults and often present with metastases (20-50%) or wide local invasion. As PDTC and HGDTC may be radioactive iodine resistant, post-surgical therapy may consist of external beam radiotherapy or targeted, mutation-dependent chemotherapy, such as tyrosine kinase inhibitors. Ten-year disease specific survival is as low as 50%. Awareness of high-grade features in the diagnostic setting is important for patient prognosis and triage of tissue for molecular analysis in order to guide relevant clinical management and therapy.

Glomus tumours of the knee: a case series

AIM

To review clinical and magnetic resonance imaging (MRI) features of patients with glomus tumour of the knee, and compare the present findings with cases from the English literature.

MATERIALS AND METHODS

The orthopaedic oncology and pathology databases at The University of Chicago were reviewed for cases of glomus tumour and small subcutaneous anterior knee masses. For all glomus tumours, the site of the tumour and age and sex of the patient were recorded. For those tumours arising in the knee, the symptom profile and MRI characteristics were recorded. The English literature was reviewed for cases describing glomus tumours in the knee.

RESULTS

Thirty-four patients with glomus tumour were recorded. Five glomus tumours occurred in the anterior knee, all in men aged ≥30 years, four of whom had a several-year history of pain prior to diagnosis. MRI showed small (<2 cm) nodular enhancing masses. Review of the English literature supports the anterior knee as a common location for lower-extremity glomus tumours, with a male predominance and several years of pain preceding diagnosis.

CONCLUSION

Although rare, glomus tumours occur in the knee. Unlike the classic description of glomus tumours occurring in the fingers most typically in women <30 years of age, those that occur in the knee tend to do so in men >30 years, and many years of pain can precede diagnosis. The astute radiologist may be the first to suggest this diagnosis if a small, painful, enhancing, nodular subcutaneous mass is noted on knee MRI examinations.

IgG4-related disease mimicking gynecologic malignancy

Immunoglobulin G4 (IgG4) related disease is a systemic disease that causes fibrosis, tumor-like nodules, and lymphoid hyperplasia with infiltration of IgG4 positive plasma cells. It can manifest in many organ systems; however, there are few cases that report gynecologic organ involvement. It is crucial to correctly diagnose IgG4-related disease versus malignancy because the former is treated with glucocorticoids or rituximab. In this case report, we describe two patients in which IgG4-related disease mimics gynecologic cancer. In the first case, an 85 year old woman presented with diffuse lymphadenopathy and a uterine mass concerning for malignancy. Biopsies were negative for carcinoma. Inguinal lymph node biopsy demonstrated IgG4 positive plasma cells and the patient was treated with rituximab therapy given concurrent severe rheumatoid arthritis. In the second case, a 35 year old woman under surveillance for Stage IB2 squamous cell carcinoma of the cervix (status post definitive chemoradiation therapy) presented with fluorodeoxyglucose (FDG) avid paraaortic lymph nodes on positron emission tomography (PET) imaging with subsequent negative paraaortic lymph node biopsies. Serial imaging and biopsies remained inconclusive despite ongoing diffuse lymphadenopathy and clinical concern for recurrence. Supraclavicular lymph node excision was performed which demonstrated lymphoid hyperplasia with increased IgG4 plasma cells and no evidence of carcinoma, supporting the diagnosis of IgG4-related disease. The patient was treated with high dose steroids with clinical improvement and resolution of abnormal imaging findings. We demonstrate that IgG4-related disease can present with FDG-avid lesions on PET imaging and lymphadenopathy that mimics primary or recurrent gynecologic malignancy. While rare, we conclude the IgG4-related disease is an important differential diagnosis to consider in the workup of primary or recurrent gynecologic malignancy and highlights the value of PET imaging to identify unusual patterns of lymphadenopathy and guide histologic confirmation of disease.

The Significance of RAS-Like Mutations and MicroRNA Profiling in Predicting Malignancy in Thyroid Biopsy Specimens

In cytologically indeterminate thyroid nodules undergoing molecular testing, estimated risk of malignancy is variable. Identification of a non-cancer-specific mutation (RAS-like) confirms a neoplastic process but does not differentiate between benign, malignant, and low-risk neoplasms. This study aims to retrospectively evaluate institutional experience of Interpace (ThyGeNEXT^® and ThyraMIR^®; Pittsburgh, PA) testing and to determine the rate of malignancy in resected nodules, stratified by mutational analysis and microRNA profile. Of 1917 fine need aspirations, 140 (7.3%) underwent Interpace testing: 47 (33.6%) were molecular-not-benign (harbored mutation, fusion, and/or positive miRNA) and 93 (66.4%) were molecular-benign (no mutations or fusions and negative microRNA). Surgery was spared in 79.6% of molecular-benign and 61.4% of all tested patients. Fifty-four (38.6%) underwent resection. Seventeen (89.5%) of the resected molecular-benign were benign and 2 were malignant. Thirteen (37.1%) of the resected molecular-not-benign were benign, 7 (20%) were noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), and 15 (42.9%) were malignant (p < 0.05, negative predictive value (NPV) 89.4-95.6%, positive predictive value (PPV) 22.3-42.8%). Most molecular-not-benign (72.3%) had RAS-like mutation. Twenty-three were resected: 3 were malignant and 7 were NIFTP. Nodules with non-RAS-like mutations (BRAF V600E-like, others) were more likely to be malignant than RAS-like (H/N/KRAS, BRAF K601E) (p < 0.05, NPV 86.9-96.5%, PPV 100%). Most nodules had RAS-like mutations and most were benign or low-risk neoplasms (NIFTP). This study supports the role of histologic examination in the distinction of malignancy in RAS-like thyroid neoplasms and underscores the role of molecular testing in risk stratification, patient counseling, and operative management.

NUTM1 -rearranged Carcinoma of the Thyroid : A Distinct Subset of NUT Carcinoma Characterized by Frequent NSD3 - NUTM1 Fusions

NUT carcinoma (NC) is a rare subtype of squamous cell carcinoma defined by NUTM1 rearrangements encoding NUT fusion oncoproteins (the most frequent fusion partner being BRD4 ) that carries a very poor prognosis, with most patients dying in under 1 year. Only rare primary thyroid NCs have been reported. Here, we evaluated a series of 14 cases. The median patient age at diagnosis was 38 years (range: 17 to 72 y). Eight of 13 cases with slides available for review (62%) showed a morphology typical of NC, whereas 5 (38%) had a non-NC-like morphology, some of which had areas of cribriform or fused follicular architecture resembling a follicular cell-derived thyroid carcinoma. For cases with immunohistochemistry results, 85% (11/13) were positive for NUT on biopsy or resection, though staining was significantly decreased on resection specimens due to fixation; 55% (6/11) were positive for PAX8, and 54% (7/13) for TTF-1. Tumors with a non-NC-like morphology were all positive for PAX8 and TTF-1. The fusion partner was known in 12 cases: 9 (75%) cases had a NSD3-NUTM1 fusion, and 3 (25%) had a BRD4-NUTM1 fusion. For our cohort, the 2-year overall survival (OS) was 69%, and the 5-year OS was 58%. Patients with NC-like tumors had a significantly worse OS compared with that of patients with tumors with a non-NC-like morphology ( P =0.0462). Our study shows that NC of the thyroid can mimic other thyroid primaries, has a high rate of NSD3 - NUTM1 fusions, and an overall more protracted clinical course compared with nonthyroid primary NC.

Secretory carcinoma of the salivary gland: a multi-institutional clinicopathologic study of 90 cases with emphasis on grading and prognostic factors

Secretory carcinoma (SC) is a rare form of salivary carcinoma that was first described in 2010 and is characterized by ETV6::NTRK3 fusion in most cases. In this large retrospective study, we aimed to identify adverse clinicopathologic factors and propose a prognostically relevant grading scheme for SC.

METHODS

A detailed clinicopathologic review was conducted on 90 SCs from the major and minor salivary glands.

RESULTS

The median age at presentation was 50 years (range: 7-93). Sixty-nine (77%) tumours originated from major salivary glands, whereas the remaining 21 involved minor salivary glands.Six cases (7%) had cervical nodal metastasis. Only lymphovascular invasion (LVI) was associated with a risk of nodal metastasis (P < 0.05). The 5-year disease-specific survival and disease-free survival (DFS) were 98% and 87%, respectively. On univariate survival analysis, adverse prognostic factors associated with decreased DFS included minor salivary gland origin, atypical mitosis, high mitotic index, high-grade transformation (HGT), necrosis, nuclear pleomorphism, infiltrative tumour border, fibrosis at the invasive front, LVI, positive margin, and advanced pT stage (P < 0.05). When adjusted for pT stage and margin status, mitotic index, LVI, nuclear pleomorphism, and HGT remained as independent prognostic factors.

CONCLUSION

We therefore propose a two-tiered grading system for SC. The low-grade SC is defined as those with <5 mitoses /10 high-power fields and no tumour necrosis, and high-grade SC as those with ≥5 mitoses /10 high-power fields and/or necrosis. This proposed grading system can be useful to risk stratify patients with SC for appropriate clinical management.

Laryngeal and pharyngeal actinomycosis: a systematic review and report of 3 cases

INTRODUCTION

Actinomycosis is a granulomatous infection that rarely involves the larynx or pharynx. Three cases of actinomycosis of the larynx or pharynx from our institution were reviewed and a systematic literature review was performed to better define surgical management, antibiotic therapy, risk factors, and incidence of recurrence or complications.

MATERIALS AND METHODS

PubMed/Medline, Cochrane, Embase, and Google Scholar were searched on November 30, 2021 using the terms "laryngeal actinomycosis", "pharyngeal actinomycosis", "actinomycosis AND larynx", and "actinomycosis AND pharynx." Articles which did not describe appropriate sites or were non-English were excluded. Results were collected for demographic information, site(s) of infection, comorbidities, lesion characteristics and treatments.

RESULTS

Along with three cases reported from our institution, 40 unique cases were reviewed from 37 studies for a total of 43 patients (Table 1). 34 (81.0 %) of the patients were male with the highest incidence of infection in the seventh decade (54.8 %). The most common site for the infection was the larynx (69.0 %) followed by the pharynx (16.7 %). Risk factors included a history of radiation therapy, immunosuppression, inhalational irritant, and diabetes (Table 3). The duration of antibiotic therapy varied greatly, from one month to one year and total follow up ranged from 1 month to 2.5 years (Table 1).

CONCLUSIONS

A comprehensive review of the literature on pharyngolaryngeal actinomycosis shows that this infection has increased prevalence within the head and neck cancer patient population. Similar to cervicofacial actinomycosis, these atypical sites have shown favorable responses to extended antibiotic therapy and generally do not require aggressive surgical management.

Graves' disease and papillary thyroid carcinoma: case report and literature review of a single academic center

BACKGROUND

Graves' disease (GD) and papillary thyroid cancer (PTC) can be concomitant. The existence of a link between these entities has long been investigated, but a clear correlation hasn't been established. We report a case of GD resistant to medical treatment in which surgery revealed unsuspected PTC and we aim to study the prevalence of PTC in Graves' disease, its clinical characteristics and review of the literature.

CASE PRESENTATION

Report of a 32 yo man who presented with weight loss and was found to be biochemically hyperthyroid. Antibodies were positive. Incremental doses of methimazole provided no improvement in thyroid tests. Hypervascularity and a spongiform nodule were noted on ultrasound. Thyroid uptake and scan showed 70.2% uptake. Thyroidectomy was performed due to inadequate therapeutic response. Pathology revealed PTC with extrathyroidal extension and positive lymph nodes. A retrospective review (2000-2021) and literature review of PTC in GD was performed. Clinical data were reviewed. Statistical analysis was calculated to identify correlations. 243 GD patients had total thyroidectomy at an academic center, 50 (20%) had PTC, 14% were microcarcinomas. 76% of cases were less than 55yo, 82% female, 78% stage 1, PTC diagnosis was incidental in 48%, hyperthyroidism was difficult to treat in 10% and only 2% had recurrence of PTC. There was no correlation between demographic or clinical data.

CONCLUSIONS

Evidence is controversial with some studies showing GD does not affect PTC prognosis. PTC may not be well recognized in GD, pre-operative assessment should consider risk of cancer.

Large tracheoesophageal granular cell tumor: An atypical case presentation, location, and management

Introduction

Presentation of case

Conclusion

•

Granular cell tumors (GCT) are rare tumors of the head and neck.

•

A 42-year-old man presented to the Emergency Department after a motor vehicle accident with a 3.2 × 5.5 cm mass anterior to the esophagus and posterior to the tachea.

•

The patient underwent a transcervical excision of the retrotracheal tumor, which was positive for CD68, CD163, S100, and SOX10, confirming a GCT.

•

This is a distinctive presentation of a large (5.5cm) GCT in the plane between the trachea and esophagus that hasn't been shown in the literature

Multimodality management of sinonasal teratocarcinosarcoma in a 76‐year‐old Alaska Native female during the COVID‐19 pandemic

Sinonasal teratocarcinosarcoma is a rare, highly aggressive tumor of the anterior skull base composed of malignant epithelial, mesenchymal, and neural tissue. Examination of cases in patients in minority populations is important in order to better understand the behavior of this neoplasm and outcomes of treatment in our nation's diverse population.

Practical immunohistochemistry in the classification of salivary gland neoplasms

Diagnosis of salivary gland neoplasms can be challenging for surgical pathologists due to low incidence of tumors as well as overlapping histologic features. On small biopsy, the most important information to be conveyed for clinical management is the distinction between a benign/low grade tumor and a high grade carcinoma. This review will discuss the differential diagnosis of salivary gland tumors based on four broad morphologic patterns: basaloid/tubular/cribriform, (micro)cystic/secretory/mucinous, solid-nested/clear-spindled, and oncocytic/oncocytoid. With the assistance of immunohistochemistry, demonstration of the number of cell types (mainly epithelial versus myoepithelial/basal) can further subclassify tumors within these morphologic categories. Additional tumor-specific immunomarkers are useful in some cases. Underlying tumor-specific genetic anomalies can be of value, however, immunohistochemical correlates are only available for some. When used judiciously, in the correct morphologic context, and with knowledge of their limitations, immunohistochemical stains can aid in differentiating tumors with similar morphology.

Primary Desmoplastic Small Round Cell Tumor of the Femur: Case Report and Review of a Rare Intraosseous Malignancy

Background: Desmoplastic small round cell tumors (DSRCT) are malignant neoplasms of young males arising most commonly in the abdominopelvic cavity, with a subset originating from extra-abdominal soft tissues. As either primary or metastatic lesions, they are rare in intraosseous sites. Case Presentation: We describe the fifth report of primary DSRCT of bone. A healthy 18-year old male presented with a blastic, 17 cm lesion within the left distal femur, suspicious for osteosarcoma or Ewing sarcoma. Subsequent biopsy revealed nests of small round blue cells infiltrating through a desmoplastic stroma. These cells were diffusely positive for epithelial markers, with paranuclear staining for desmin and focal reactivity with NSE. Break-apart FISH revealed a rearrangement in EWSR1, and RNA fusion panel confirmed WT1 as its partner in the pathognomonic t(11;22)(p13;q12) rearrangement. PET/CT showed widespread metastatic disease to visceral and bony sites. Conclusions: Due to their rarity as well as clinicopathologic and immunomorphologic overlap, primary intraosseous DSRCT can create diagnostic challenges with the more frequently encountered tumors of bone.

Distinguishing Parathyromatosis, Atypical Parathyroid Adenomas, and Parathyroid Carcinomas Utilizing Histologic and Clinical Features

Parathyromatosis is displaced parathyroid tissue in the neck and mediastinum related to prior surgery. Parathyromatosis can be difficult to distinguish from atypical adenoma and parathyroid carcinoma. The aim of this study is to evaluate clinical and morphologic features that may differentiate parathyromatosis, atypical adenoma, and parathyroid carcinoma. Cases of parathyromatosis, atypical adenoma, and parathyroid carcinoma were identified. Index cases were reviewed by consensus for histologic features, including stromal, cytologic/architectural, and invasive features. Ki67 was performed on index cases and scored using the Adsay method. Clinical information was gathered from the electronic medical record. 4 parathyromatosis, 17 atypical adenoma, and 6 parathyroid carcinoma were included. Parathyroid carcinomas were more likely to display coarse chromatin with nucleoli (P = 0.04), infiltrative invasion (P < 0.01), and metastasis (P < 0.01). Only parathyromatosis showed circumscribed invasion. Infiltrative invasion was more common in cases with progression (P = 0.046) and metastasis (P < 0.001). Necrosis and perineural invasion were only present in cases with progression and were more frequent in cases with metastasis (P = 0.079 and P = 0.19, respectively). There were no differences in presence of a fibrous capsule, capsular invasion, intralesional fibrous bands, random endocrine atypia, solid growth, Ki67 index, gland size/weight, serum PTH/calcium levels, and locoregional recurrence rates. There is overlap in the histologic features in parathyromatosis, atypical adenoma, and parathyroid carcinoma. While perineural, vascular, and infiltrative soft tissue invasion should remain diagnostic of malignancy, other atypical features such as solid growth, coarse chromatin with nucleoli, and necrosis should raise concern for recurrence and/or metastasis, and can be present in parathyroid lesions with and without recurrence.

The Controversy of Lateral Aberrant Thyroid and the use of BRAF Immunostain

A 29-year-old women presents with primary intrathyroidal papillary thyroid carcinoma (BRAF VE1 positive) with morphologically recognizable metastases to cervical lymph nodes (BRAF VE1 positive) as well as a focus of bland-appearing thyroid follicles within the capsule of a level II lymph node (BRAF VE1 negative). There exist various theories regarding the possible developmental origins of "benign" intranodal thyroid tissue in the lateral neck. While the true nature of the bland follicles may not be definitively resolved in this case, these findings are suggestive that they do not represent metastasis from the main papillary thyroid carcinoma. Additional insight into this unusual phenomenon may be gathered by more specific clonal analysis of these microscopic foci.

High Rates of Ultraviolet-Signature Mutations in Squamous Cell Carcinomas of the Parotid Gland and Prognostic Implications

In the absence of clear pathologic differences, clinical history may differentiate potential primary parotid squamous cell carcinomas (SCC) from metastases. The presence of an ultraviolet (UV) signature can distinguish between tumors of cutaneous and non-cutaneous origin. This study aimed to investigate rates of UV signature mutations in squamous cell carcinomas of the parotid gland as well as differences in clinical features between tumors of cutaneous and non-cutaneous origin. Clinical and pathologic data were collected from 71 patients with SCC involving the parotid gland, of which 48 had cutaneous, 10 had mucosal, and 13 had no history of SCC. In 34 available cases, genomic DNA was isolated from formalin-fixed paraffin-embedded tissue specimens and sequenced using a targeted hybrid capture 1213 gene panel. Tumor mutational burden and COSMIC (Catalogue of Somatic Mutations in Cancer) mutational signatures were calculated. Most (74%) were UV-positive. Patients with UV-positive tumors were significantly older, white, and had higher rates of sun exposure. Patients with UV-negative tumors had a significantly higher mortality rate and shorter time to death: 6 (67%) died of disease with a median time to death of 9 months compared to 5 (20%) UV-positive patients who died of disease with a median time to death of 32 months. Pathologic features did not significantly vary by clinical history or UV status. The presence of a UV-signature combined with clinical history can be used to determine the primary source of SCC involving the parotid gland. UV-positivity may reflect a less aggressive disease course in an older population.

SALL-4 and Beta-Catenin Expression in Sinonasal Teratocarcinosarcoma

Sinonasal teratocarcinosarcoma (SNTCS) is a rare, aggressive malignancy that displays a heterogeneous combination of malignant blastema-like, epithelial and mesenchymal components. Its exact histogenesis is unknown with hypotheses ranging from true germ cell derivation to origin from pluripotent stem cells. However, despite this tumor's multiphenotypic histology, which includes frequent glandular, squamous, and neuroectodermal differentiation similar to adnexal germ cell tumors, SNTCS appears to have some differences from adnexal teratomas. For example, unlike adnexal teratomas, SNTCS has never been described as a component in a mixed germ cell tumor. Accurate recognition of SNTCS is difficult due to its rarity and histologic overlap with other sinonasal tumors. It is even more problematic on biopsy, since not all elements may be present in small samples. SNTCS can also share similar staining patterns with other neoplasms in the differential diagnosis. A recent study found nuclear β-catenin expression in a single TCS, but this has yet to be confirmed in additional cases. SALL-4, a marker of germ cell tumors, has not been examined. We performed β-catenin and SALL-4 immunohistochemistry on whole sections of 7 SNTCS and 19 other sinonasal neoplasms to assess whether β-catenin and SALL-4 are of utility in establishing a diagnosis of SNTCS. Intensity of expression and percentage of staining was noted for each tumor. For SNTCS, distribution of staining within each histologic component (immature neuroectodermal, epithelial, and mesenchymal) was also documented. Nuclear β-catenin expression was not identified in any SNTCS, with all cases demonstrating membranous expression (6 cases) or cytoplasmic and membranous expression (1 case). SALL-4 immunohistochemistry, however, was relatively sensitive (85.7%) and specific (89.5%) for SNTCS. SALL-4 expression was also identified in one poorly differentiated neuroendocrine carcinoma and one case of sinonasal undifferentiated carcinoma. SALL-4 appears to have utility in distinguishing SNTCS from other high grade sinonasal tumors.

Artificial Intelligence Can Cut Costs While Maintaining Accuracy in Colorectal Cancer Genotyping

Rising cancer care costs impose financial burdens on health systems. Applying artificial intelligence to diagnostic algorithms may reduce testing costs and avoid wasteful therapy-related expenditures. To evaluate the financial and clinical impact of incorporating artificial intelligence-based determination of mismatch repair/microsatellite instability status into the first-line metastatic colorectal carcinoma setting, we developed a deterministic model to compare eight testing strategies: A) next-generation sequencing alone, B) high-sensitivity polymerase chain reaction or immunohistochemistry panel alone, C) high-specificity panel alone, D) high-specificity artificial intelligence alone, E) high-sensitivity artificial intelligence followed by next generation sequencing, F) high-specificity artificial intelligence followed by next-generation sequencing, G) high-sensitivity artificial intelligence and high-sensitivity panel, and H) high-sensitivity artificial intelligence and high-specificity panel. We used a hypothetical, nationally representative, population-based sample of individuals receiving first-line treatment for de novo metastatic colorectal cancer (N = 32,549) in the United States. Model inputs were derived from secondary research (peer-reviewed literature and Medicare data). We estimated the population-level diagnostic costs and clinical implications for each testing strategy. The testing strategy that resulted in the greatest project cost savings (including testing and first-line drug cost) compared to next-generation sequencing alone in newly-diagnosed metastatic colorectal cancer was using high-sensitivity artificial intelligence followed by confirmatory high-specificity polymerase chain reaction or immunohistochemistry panel for patients testing negative by artificial intelligence ($400 million, 12.9%). The high-specificity artificial intelligence-only strategy resulted in the most favorable clinical impact, with 97% diagnostic accuracy in guiding genotype-directed treatment and average time to treatment initiation of less than one day. Artificial intelligence has the potential to reduce both time to treatment initiation and costs in the metastatic colorectal cancer setting without meaningfully sacrificing diagnostic accuracy. We expect the artificial intelligence value proposition to improve in coming years, with increasing diagnostic accuracy and decreasing costs of processing power. To extract maximal value from the technology, health systems should evaluate integrating diagnostic histopathologic artificial intelligence into institutional protocols, perhaps in place of other genotyping methodologies.

Deep learning prediction of BRAF-RAS gene expression signature identifies noninvasive follicular thyroid neoplasms with papillary-like nuclear features

Noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) are follicular-patterned thyroid neoplasms defined by nuclear atypia and indolent behavior. They harbor RAS mutations, rather than BRAFV600E mutations as is observed in papillary thyroid carcinomas with extensive follicular growth. Reliably identifying NIFTPs aids in safe therapy de-escalation, but has proven to be challenging due to interobserver variability and morphologic heterogeneity. The genomic scoring system BRS (BRAF-RAS score) was developed to quantify the extent to which a tumor's expression profile resembles a BRAFV600E or RAS-mutant neoplasm. We proposed that deep learning prediction of BRS could differentiate NIFTP from other follicular-patterned neoplasms. A deep learning model was trained on slides from a dataset of 115 thyroid neoplasms to predict tumor subtype (NIFTP, PTC-EFG, or classic PTC), and was used to generate predictions for 497 thyroid neoplasms within The Cancer Genome Atlas (TCGA). Within follicular-patterned neoplasms, tumors with positive BRS (RAS-like) were 8.5 times as likely to carry an NIFTP prediction than tumors with negative BRS (89.7% vs 10.5%, P < 0.0001). To test the hypothesis that BRS may serve as a surrogate for biological processes that determine tumor subtype, a separate model was trained on TCGA slides to predict BRS as a linear outcome. This model performed well in cross-validation on the training set (R2 = 0.67, dichotomized AUC = 0.94). In our internal cohort, NIFTPs were near universally predicted to have RAS-like BRS; as a sole discriminator of NIFTP status, predicted BRS performed with an AUC of 0.99 globally and 0.97 when restricted to follicular-patterned neoplasms. BRAFV600E-mutant PTC-EFG had BRAFV600E-like predicted BRS (mean -0.49), nonmutant PTC-EFG had more intermediate predicted BRS (mean -0.17), and NIFTP had RAS-like BRS (mean 0.35; P < 0.0001). In summary, histologic features associated with the BRAF-RAS gene expression spectrum are detectable by deep learning and can aid in distinguishing indolent NIFTP from PTCs.

Differentiating low and high grade mucoepidermoid carcinoma of the salivary glands using CT radiomics

Background

The purpose of this study is to determine if Haralick texture analysis on CT imaging of mucoepidermoid carcinomas (MEC) can differentiate low-grade and high-grade tumors.

Methods

A retrospective review of 18 patients with MEC of the salivary glands, corresponding CT imaging and pathology report was performed. Tumors were manually segmented and image analysis was performed to calculate radiomic features. Radiomic features were compared between low-grade and high-grade MEC. A multivariable logistic regression model and receiver operating characteristic analysis was performed.

Results

A total of 18 patients (mean age, 51, range 9-83 years, 8 men and 10 women) were included. Nine patients had low-grade pathology and nine patients had high-grade pathology. Of the 18 cases, 7 (39%) occurred in the parotid gland and 11 (61%) occurred in minor salivary glands. No individual feature was significantly different between low-grade and high-grade MEC. A logistic regression model including surface regularity, energy and information measure II of correlation was performed and was able to predict high-grade MEC accurately (sensitivity 89%, specificity 68%). The area under the receiver operating characteristic curve was 0.802.

Conclusions

High-grade MEC tend to have a low energy, high correlation texture as well as surface irregularity. Together, these three features may comprise a tumor phenotype that is able to predict high-grade pathology in MECs.

Histopathologic and clinical outcomes of Milan System categories "non-diagnostic" and "non-neoplastic" of salivary gland fine needle aspirations

INTRODUCTION

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) specifies six categories with estimated risks of malignancy (ROM) and suggested management. The estimated ROM is 25% for Non-Diagnostic (ND) category, and 10% for Non-Neoplastic (NN). This study aimed to investigate histopathologic and clinical outcomes of MSRSGC categories ND and NN at the authors' institution.

MATERIALS AND METHODS

Cytopathology fine needle aspiration reports from 2008-2020 were searched for the word "salivary", "parotid", and "submandibular". Cases fitting Non-Diagnostic (ND) and Non-Neoplastic (NN) categories were identified. Follow-up cyto-/histopathologic and clinical data were extracted.

RESULTS

There were 43 ND and 46 NN cases. The average age was 58.3 years. Neoplastic lesions were found in 13 of 43 (30%) ND and 3 of 46 (6.5%) NN. The rate of malignancy in ND category was 14.0% (6/43) and 0% (0/46) in NN category. Four cases in ND (9.3%) and 6 (13.0%) in NN had no neoplasm and instead had an underlying reactive condition (e.g., chronic sialadenitis) or inflammatory lesion (e.g., lymphoepithelial cyst) on histologic follow-up. There was no follow-up pathology in 46.5% NDs (20/43) and 82.6% NNs (38/46); however, no lesions were apparent clinically with a mean follow-up of 3 years and 1.5 years, respectively.

CONCLUSIONS

MSRSGC categories ND and NN are helpful for reporting salivary gland FNA results. With proper clinical and radiologic correlation, ROM of NN is low; however, ROM of ND remains significant. Repeat FNA after correlation for ND cases seems prudent as neoplasms and malignancies may have gone undetected.

Metastatic HPV-Associated Oropharyngeal Versus Primary Pulmonary Squamous Cell Carcinoma: is p16 Immunostain Useful?

The lungs are a common site of metastasis of head and neck (H&N) squamous cell carcinomas (SCC). This study attempts to define p16 immunoexpression and presence of HPV in primary SCC of the lung and determine their usefulness in discriminating between primary lung SCC and metastasis from HPV-associated oropharyngeal primary. Pathology archives were searched for patients with SCC of the lung without SCC elsewhere. Tissue microarray was constructed and immunohistochemistry performed using anti-p40 and anti-p16 antibodies. All cases were tested for HPV viral proteins E6/E7 by RNA in situ hybridization (ISH) and available positive cases for HPV DNA by polymerase chain reaction (PCR). Eight of 25 (32%) showed cytoplasmic and nuclear expression of p16: 2 (8%) strong and 2 (8%) moderate in > 70% of tumor cells; 1 (4%) strong, 1 (4%) moderate, and 1 (4%) weak in 50-70% of tumor cells; 1 (4%) weak in < 50% of tumor cells. E6/E7 mRNA ISH was negative in all cases. Seven of 8 (87.5%) p16-expressing cases were available for testing by HPV PCR; all were negative for HPV DNA. A retrospective control group of 12 patients with possible SCC metastatic to lung was also identified; high-risk HPV DNA was present in 3, confirming metastasis. p16 expression in lung SCC is not uncommon and may not discriminate between primary pulmonary SCC and metastasis from HPV-associated oropharyngeal primary. Confirmatory HPV testing (high risk HPV DNA or E6/E7 mRNA) is recommended to differentiate metastasis from oropharyngeal primary from two separate primaries.

Comparison of Molecular Methods and BRAF Immunohistochemistry (VE1 Clone) for the Detection of BRAF V600E Mutation in Papillary Thyroid Carcinoma: A Meta-Analysis

The evaluation of surgically resected papillary thyroid carcinomas (PTC) by immunohistochemistry (IHC) for BRAF mutation has diagnostic, prognostic and therapeutic implications. The goal of this meta-analysis was to perform a systematic review of studies using the VE1 clone (specific for detection of the BRAF V600E mutation) on formalin-fixed paraffin embedded (FFPE) thyroid surgical resection specimens for primary papillary thyroid carcinoma. The authors' molecular techniques, immunohistochemistry protocols, and scoring methods for VE1 immunostaining were also evaluated. This study included 4079 PTCs representing data from 23 studies. The results extracted from each study were split into two different groups, direct sequencing group or PCR group, based on the molecular "gold standard" method used to compare VE1 IHC staining. In the direct sequencing group, the IHC sensitivity was 100% (95% CI 0.97-1.00) and specificity 84% (95% 0.72-0.91). In the PCR group the sensitivity was 98% (95% CI 0.96-0.99) and specificity 89% (95% CI 0.82-0.94). Although immunohistochemical procedures varied by author, the overall performance of the VE1 clone shows that it is highly sensitive and relatively specific for detecting the BRAF V600E mutation in surgical resection specimens. However, standardization of immunohistochemical procedural method and scoring/interpretation criteria may improve the reliability and reproducibility for the use of VE1 clone for future practice.

Mesenchymal lesions of the vulva

Mesenchymal lesions of the vulva include site-specific entities limited to the lower genital tract, as well as a range of non-site-specific tumors that are more common at extragenital sites. Site-specific lesions include fibroepithelial stromal polyp, cellular angiofibroma, angiomyofibroblastoma, and aggressive angiomyxoma. Non-site-specific tumors that may occur in the vulva include those of smooth muscle, skeletal muscle, vascular, neural, adipocytic, and uncertain differentiation. This review discusses both site-specific and non-site-specific vulvar mesenchymal lesions including non-neoplastic proliferations, benign neoplasms, locally aggressive neoplasms with a predilection for local recurrence, neoplasms of indeterminate biologic potential, and frankly malignant neoplasms with a high risk of distant metastasis and death. Accurate diagnosis is essential for proper management, and is facilitated by correlation with clinical findings and targeted application of immunohistochemical and molecular studies.

Prognostic Parameters in Differentiated Thyroid Carcinomas

Differentiated thyroid carcinomas make up most thyroid malignancies. The AJCC staging system and the ATA risk prediction system are the best predictors of mortality and recurrence, respectively. Key factors to be identified and reported by pathologists are reviewed in this article and include: (1) aggressive histologic variants of papillary thyroid carcinoma (including tall cell, columnar cell, and hobnail variants); (2) presence of gross extrathyroidal extension (into skeletal muscle or adjacent organs); (3) angioinvasion (including number of foci); (4) number, anatomic level, and size of lymph node metastases; (4) extranodal extension; (5) genetics (especially BRAF V600E or TERT promoter mutation).

Art as a Learning Tool: Medical Student Perspectives on Implementing Visual Art into Histology Education

Creating visual art to teach and learn histologic concepts is uncommon. A pilot visual art program was developed for use in first-year medical student courses that include histology with the hypothesis that creating visual art would subjectively improve the learning process and lead to learner-based personal incorporation of art into in future learning. Prior to the term, volunteers (n=25) were recruited from 89 first-year medical students. The volunteer group was given art supplies and encouraged to draw histologic images in a free-form setting without restrictions. The control group (n=64) consisted of non-volunteers. Pre- and post-term surveys were distributed to all students, of which 72% and 45% completed the surveys, respectively. Regardless of participation, a majority of students viewed art as a valuable tool to learn medicine prior to and following the term (73% and 82.5%, respectively), however less than half admitted to using art to learn medical concepts (42% and 40%, respectively). In the post-term survey, a higher percentage of students in the experimental group stated they will use art to learn medical concepts in the future (75% vs 40.6%). Most students considered art to be a valuable resource to learn concepts in medicine, including all the students who participated in the art program. Based on the number of students who reported intent to change behavior, the initial hypothesis is supported. Many students favor incorporation of visual art into medical education, we believe that creating visual art may be a worthwhile adjunct tool for histology education.

An Evaluation of CD61 Immunohistochemistry in Identification of Vascular Invasion in Follicular Thyroid Neoplasms

The identification of vascular invasion in follicular thyroid neoplasms is essential for categorizing lesions as benign (follicular adenomas) or malignant (follicular thyroid carcinomas). Among the histologic criteria diagnostic of true vascular invasion is tumor-cell associated thrombosis, including fibrin deposition and platelet clumping. This study aims to evaluate whether an immunohistochemical stain for the platelet-associated protein CD61 could assist in identifying tumor-associated thromboses and thereby confirm vascular invasion in follicular thyroid neoplasms. Histologic review and CD61 immunostaining of 19 atypical follicular adenomas, 13 non-metastatic follicular thyroid carcinomas, and 11 metastatic follicular thyroid carcinomas was performed. Linear arrays or clustered groups of CD61-expressing intravascular platelets were present in 51% of cases overall, including 54% of follicular thyroid carcinomas and 47% of follicular adenomas, mostly within intracapsular or peritumoral vessels. In three follicular thyroid carcinomas (all with distant metastases), CD61-expressing platelets were present in association with intravascular tumor cells. This finding was not present in adenomas. CD61 staining alone did not distinguish between atypical follicular adenomas, non-metastatic carcinomas, and metastatic carcinomas. When present in association with intravascular tumor cells, however, CD61-expressing platelets may serve as a marker for vascular invasion and aid in the diagnosis of follicular thyroid carcinoma.

Fine-needle aspiration of dermatofibrosarcoma protuberans metastasizing to hemithorax with superior vena cava compression: Case report and literature review

Dermatofibrosarcoma protuberans (DFSP) is a low-grade spindle cell tumor of the skin commonly arising on the trunk and extremities which tends to be slow growing yet locally aggressive. DFSPs are associated with a good prognosis when surgical excision with negative margins is achieved. Although local recurrences occur up to 50% of incompletely resected cases, distant metastases are very rare. Here, we report a case of DFSP metastasizing to the right hemithorax diagnosed by an endobronchial ultrasound-guided fine-needle aspiration (FNA) 9 years after initial presentation. The aspirate showed a bland spindle cell proliferation that was morphologically similar to the original skin excision; the storiform pattern was particularly prominent in tumor-tissue fragments in the cellblock. Immunostaining showed strong, diffuse positivity for CD34. Molecular studies demonstrated a characteristic COL1A1/PDGFB fusion in both original and metastatic specimens. A review of the literature revealed that metastatic DFSP most often involves the lungs, occurs usually in cases with fibrosarcomatous transformation and after a local recurrence, and presents on average 4.5 years after the original diagnosis. This case did not show fibrosarcomatous transformation or local recurrence prior to metastasis 9 years later. In summary, it is important to consider the potential for metastases years after a nonrecurring primary DFSP, despite its rarity. Cytologic features when complemented by ancillary studies and awareness of the patient's prior clinical history permit a confident diagnosis of metastatic DFSP by FNA. In addition, by confirming the characteristic translocation, tyrosine-kinase inhibitor imatinib can provide additional treatment options for unresectable metastatic DFSP.

A Proposal for Separation of Nuclear Atypia and Architectural Atypia in Bethesda Category III (AUS/FLUS) Based on Differing Rates of Thyroid Malignancy

Objectives

Bethesda category III (atypia of undetermined significance/follicular lesion of undetermined significance) includes sparsely cellular specimens with nuclear atypia (3N) and/or architectural atypia (3A). This study investigates whether the two types of atypia have different rates of malignancy (ROMs).

Methods

Cytologic and histologic diagnoses of resected thyroid nodules were recorded. ROM was calculated for all Bethesda categories and for 3N and 3A subcategories. Possible noninvasive follicular thyroid neoplasms with papillary-like nuclear features were reviewed and removed from malignancies, and ROM was recalculated.

Results

A total of 1,396 nodules were included. ROM of 3N (33.3%-26.0%) was higher than 3A (7.7%-5.0%) (P < .0001) and was similar to suspicious for follicular neoplasm (25.0%-20.3%) (P = .3). ROM of 3A approached benign (2.4%-1.5%) (P = .02).

Conclusions

Strong consideration should be given to separating 3N (nuclear atypia with higher risk for papillary thyroid carcinoma) from 3A (architectural atypia with higher chance of being benign) to convey different ROMs.

Large Cytologically Benign Thyroid Nodules Do Not Have High Rates of Malignancy or False-Negative Rates and Clinical Observation Should be Considered: A Meta-Analysis

Background: Management of large thyroid nodules is controversial, as data are conflicting regarding overall rates of malignancy (ROM) in all nodules and frequency of false-negative fine-needle aspiration results (FNR) in cytologically benign nodules. This meta-analysis aimed to evaluate and compare ROM and FNR in small versus large nodules published in the literature. Methods: Articles indexed in PubMed, written in English, published electronically or in print on or prior to December 8 2017 were searched for "false negative thyroid size or cm" and "malignancy rates benign thyroid nodules." Three hundred fifty-two unique citations were identified. Multiple reviewers selected a final set of 35 articles that contained nodules stratified by size (3, 4, or 5 cm), with benign or all cytologic diagnoses, and with postsurgical histologic diagnoses. Multiple observers extracted data, including numbers of total, cytologically benign, and histologically malignant nodules. Size cutoffs of 3, 4, and/or 5 cm were analyzed in 14, 24, and 1 article, respectively. Results: ROM in all nodules ≥3 cm (13.1%) and ≥4 cm (20.9%) was lower than those <3 cm (19.6%) and <4 cm (19.9%; odds ratio [OR] = 0.72 [confidence interval (CI) 0.64-0.81] and OR = 0.85 [CI 0.77-0.95]). FNR in nodules ≥3 cm (7.2%) was not different from smaller nodules (5.7%; OR = 1.47 [CI 0.80-2.69]). FNR in nodules ≥4 cm (6.7%) was slightly higher than those <4 cm (4.5%; OR = 1.38 [CI 1.06-1.80]). The most frequently reported false-negative diagnosis was papillary thyroid carcinoma. Conclusions: Rates of malignancy and false-negative FNA results vary but, in most studies, are not higher in larger nodules. Patients with large, cytologically benign thyroid nodules need not undergo immediate surgical resection, as false-negative FNA rates are low and are expected to decrease in light of nomenclature revision of a subset of follicular variants of papillary thyroid carcinoma.

Histological features and prognostic significance of treatment effect in lymph node metastasis in head and neck squamous cell carcinoma

AIMS AND OBJECTIVES

Cervical lymph node metastasis in head and neck squamous cell carcinoma (HNSCC) is common. Pre-operative chemoradiotherapy (preCRT) and postoperative chemoradiotherapy (postCRT) is frequently employed in such patients. The prognostic value of viable SCC, treatment effect or no SCC in resected lymph nodes in patients who received or did not receive preCRT and postCRT was investigated.

METHODS AND RESULTS

Resected cervical lymph nodes from 146 patients with HNSCC were evaluated for viable SCC, treatment effect or no SCC. Immunostains for Ki67, cyclin D1, caspase 3 and H2AFX were performed on viable SCC or nucleate keratin debris. Clinical and histological data were correlated with tumour recurrence or persistence. Patients with nucleate keratin debris in lymph nodes had outcomes similar to those with diffuse treatment effect and no SCC. Viable tumour in lymph nodes was associated with worse prognosis in patients who received preCRT (P = 0.01). This relative worsening of prognosis was not observed in patients with oropharyngeal SCC or recurrent disease. Lower proliferation index in lymph node SCC was associated with preCRT and with worse outcomes (P = 0.0002). Overall, patients who received preCRT or postCRT had outcomes not significantly different from those who did not.

CONCLUSION

The presence of viable SCC in cervical lymph nodes has prognostic import when taken in context with the patient's history. Viable SCC in lymph nodes was significantly associated with worse outcome among patients with non-oropharyngeal SCC who received preCRT. Nucleate keratin debris should not be considered viable SCC in lymph nodes.

Aneurysmal Bone Cyst of the Maxillary Sinus with USP6 Rearrangement: Case Report of a Rare Entity and Review of the Literature

Aneurysmal bone cysts (ABCs) are benign lesions which most frequently occur in the long bones of pediatric patients. Long thought to be reactive, recent molecular advances have demonstrated that the majority of primary ABCs harbor rearrangements of the USP6 gene, confirming their neoplastic nature. Secondary ABCs arising from other lesions do not demonstrate this recurrent genetic anomaly. ABCs rarely occur in the craniofacial bones, and sinonasal ABCs are exceedingly rare. We report a case of a primary ABC arising the maxillary sinus of a 14-year-old female, which was found to harbor USP6 rearrangement. We describe the clinical, radiologic, and pathologic features of this case, and review the current literature on craniofacial ABCs. Careful histologic evaluation and genetic studies are warranted in order to confirm the rare occurrence of a primary sinonasal ABC.

Histiocytic Necrotizing Lymphadenitis Involving the Neck: Radiology-Pathology Correlation

Histiocytic necrotizing lymphadenitis is an uncommon autoimmune condition characterized by fever, leukopenia, and neck swelling. Diagnostic imaging, including ultrasound and CT, typically demonstrates conglomerates of enlarged cervical lymph nodes with hypervascular cortices and areas of necrosis. Ultimately, the diagnosis is confirmed with the histopathologic findings of paracortical coagulative necrosis with karyorrhectic debris, abundant histiocytes, and absence of neutrophils. Other potential etiologies, such as other causes of infectious lymphadenitis, tuberculosis, lymphoma, and systemic lupus erythematosus, must be excluded. These features are exemplified in this sine qua non radiology-pathology correlation article.

Educational Impact of Trainee-Facilitated Head and Neck Radiology-Pathology Correlation Conferences

The goal of this study was to evaluate the benefits of resident and fellow-facilitated radiology-pathology head and neck conferences. A total of seven resident-facilitated and six fellow-facilitated head and neck radiology-pathology cases were presented as part of the radiology department conference series. The radiology residents were surveyed regarding the perceived quality and effectiveness of the fellow-facilitated sessions. The number of publications yielded from all the cases presented was tracked. Overall, the residents assessed the quality of the fellow-facilitated conferences with an average score of 3.9 out of 5 and the overall helpfulness with an average of 3.5 out of 5. The overall average level of resident understanding among the residents for the topics presented to them by the fellows at baseline was 2.5 out of 5 and 3.4 out of 5 after the presentations, which was a significant increase (p-value < 0.01). There were three peer-reviewed publications generated from the resident presentations and four peer-reviewed publications generated from the fellow presentations, which represents a 54% publication rate collectively. Therefore, trainee-facilitated head and neck radiology-pathology conferences at our institution provide added learning and scholarly activity opportunities.

Noninvasive Follicular Thyroid Neoplasms With Papillary-like Nuclear Features Are Genetically and Biologically Similar to Adenomatous Nodules and Distinct From Papillary Thyroid Carcinomas With Extensive Follicular Growth

CONTEXT

- Proposed noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTPs), formerly noninvasive encapsulated papillary carcinoma, follicular variant (PTC-FV), is an indolent tumor with follicular growth and frequent RAS mutations.

OBJECTIVE

- To detect histologic and molecular differences separating NIFTP from follicular adenomas (FAs) and invasive carcinomas, particularly papillary carcinomas with extensive follicular growth (PTC-EFGs) and invasive encapsulated PTC-FV (IE-PTC-FV).

DESIGN

- Sixty-one tumors were reviewed histologically and reclassified into 32 NIFTPs (52%), 4 IE-PTC-FVs (7%), 14 PTC-EFGs (23%), and 11 FAs (18%). Next-generation sequencing for mutations in 50 genes was performed. Clinical outcomes were recorded.

RESULTS

- The NIFTPs and FAs were well circumscribed and unencapsulated. The FAs had bland nuclei, whereas the NIFTPs showed at least 2 of 3 (67%; sufficient) nuclear features (enlargement, irregular contours, chromatin clearing). The IE-PTC-FVs had follicular growth, sufficient nuclear features, and extensive capsular invasion. The PTC-EFGs had a median of 5% papillae with intrathyroidal invasion (broad-based, sclerotic, or small follicle growth patterns); intranuclear pseudoinclusions were present only in PTC-EFGs (9 of 14; 64%). Mutations included RAS in 20 of the 32 NIFTPs (62%), 4 of the 11 FAs (36%), and 3 of the 4 IE-PTC-FVs (75%); BRAF K601E in 1 NIFTP (3%); BRAF V600E in 5 PTC-EFGs (36%). No NIFTPs or FAs recurred or metastasized. All 4 IE-PTC-FVs (100%) had hematogenous metastasis. Two PTC-EFGs (14%) had lymphatic metastasis.

CONCLUSIONS

- The morphologic similarity and RAS mutations in FAs, NIFTPs, and IE-PTC-FVs supports the genetic similarity of those follicular neoplasms in contrast to the unique presence of BRAF V600E mutations in PTC-EFGs. Using strict diagnostic criteria supported by molecular testing, tumors with extensive follicular growth can be classified into follicular type or RAS-like (FA, NIFTP, IE-PTC-FV) versus papillary type or BRAF V600E-like (PTC-EFG).

Ubiquitin Immunostaining in Thyroid Neoplasms Marks True Intranuclear Cytoplasmic Pseudoinclusions and May Help Differentiate Papillary Carcinoma from NIFTP

Papillary thyroid carcinoma (PTC) is defined by an invasive growth pattern and classic nuclear features: enlarged, grooved, overlapping nuclei with chromatin clearing and intranuclear cytoplasmic pseudoinclusions (INCP). True INCPs are characteristic of PTC, but may infrequently be seen in noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP). Nuclear abnormalities that mimic INCP ("pseudo-pseudoinclusions") are common in a variety of thyroid lesions. H&E and ubiquitin-stained whole tissue sections of classic PTC (n = 25) and NIFTP (n = 35) were evaluated. On H&E, true INCPs were present in all (100%) PTCs and absent in all NIFTPs (0%). Pseudo-pseudoinclusions were present in 13 (37%) NIFTPs. In 24 (96%) PTCs, ubiquitin was strongly expressed within INCPs. In NIFTPs, optically clear nuclei or pseudo-pseudoinclusions did not express ubiquitin (0/35). Occasionally, nuclear vacuoles in NIFTP demonstrated a marginated staining pattern, in which strong ubiquitin expression was seen at the periphery of the nucleus, but the central pale area was negative. In addition, 2 NIFTPs demonstrated intrafollicular psammomatoid calcifications which were strongly ubiquitin-positive. Psammoma bodies in PTC were ubiquitin-negative in the majority of cases. We report a previously undescribed finding: strong ubiquitin expression in true INCPs in PTC, absence of true INCPs in NIFTP, and absence of ubiquitin expression in pseudo-pseudoinclusions in NIFTP. This finding supports the difference between true INCPs (found only in PTC) and pseudo-pseudoinclusions (found in NIFTP). Using strict histologic criteria and ubiquitin immunostaining, the presence of true pseudoinclusions may exclude a diagnosis of NIFTP. Caution should be exercised when interpreting nuclear vacuoles or pseudo-pseudoinclusions.

Synchronous and Metastatic Papillary and Follicular Thyroid Carcinomas with Unique Molecular Signatures

Despite the relatively high prevalence of thyroid cancer, the occurrence of multiple synchronous, distinct subtypes of primary thyroid carcinoma is uncommon. The incidental finding of papillary thyroid microcarcinoma in a gland with a biologically relevant follicular or medullary carcinoma is more frequent than the synchronous occurrence of multiple clinically significant carcinomas. We report a case of synchronous papillary and follicular thyroid carcinomas metastatic to lymph node and bone, respectively. Next generation sequencing showed BRAF V600E mutation in the primary papillary carcinoma and NRAS Q61R mutation in the primary follicular carcinoma and bony metastasis. To our knowledge, this is the first reported case of synchronous and metastatic primary papillary and follicular carcinomas, and the first report of synchronous BRAF V600E mutated papillary and NRAS mutated follicular carcinoma.

Role of dental hardware in oral cavity squamous cell carcinoma in the low-risk nonsmoker nondrinker population

BACKGROUND

Oral cavity squamous cell carcinoma (SCC) arising in nonsmokers and nondrinkers remains poorly characterized. We hypothesized that these patients had prior exposure to metallic dental hardware.

METHODS

We utilized a questionnaire querying the lifetime oral health status of 54 patients. Demographics and extensive oral health history were collected.

RESULTS

The majority of patients (74%) had prior exposure to metallic dental hardware. The younger population with almost exclusively oral tongue cancer had a high prevalence of metallic orthodontic braces (40%) within 15 years before diagnosis. In the 51+ year age group, 82% had crowns, dental implants, and/or dentures with metallic elements.

CONCLUSION

Exposure to metallic dental hardware has increased in the past few decades given the rise of orthodontic braces and older adults retaining more teeth. Although this study does not prove a causal relationship between oral cavity SCC and dental hardware, this is a step toward identifying and investigating their role.

Expression of Hormone Receptors and HER-2 in Benign and Malignant Salivary Gland Tumors

With the advent of targeted therapies, expression of sex hormone receptors and HER-2 in salivary gland tumors (SGTs) is of clinical interest. Previous reports of estrogen (ER) and progesterone (PR) receptor expression have varied. Androgen receptor (AR) and HER-2 overexpression are frequently reported in salivary duct carcinoma (SDC), but have not been studied systematically in other SGTs. This study examines ER, PR, AR, and HER-2 expression in SGTs. Immunohistochemistry for ER, PR, AR, and HER-2 was performed on 254 SGTs (134 malignant). ER, PR, and AR expression was scored using Allred system. HER-2 expression was scored using Dako HercepTest guidelines. FISH for HER-2 amplification was performed on select cases with HER-2 overexpression (2-3+). No SGT demonstrated strong expression of ER or PR. Combined strong AR and HER-2 expression was seen in 22 carcinomas: 14/25 SDC, 3/16 poorly differentiated, two oncocytic, and one each carcinoma ex pleomorphic adenoma, squamous cell, and intraductal carcinoma. Eighteen additional high grade carcinomas had HER-2 overexpression with absent, weak, or moderate AR expression; eight high grade carcinomas had isolated strong AR expression with 0-1+ HER-2 staining. Of 15 tested cases, six demonstrated HER-2 amplification by FISH, all of which had 3+ immunoreactivity. Neither benign nor malignant SGTs had strong expression of ER or PR. None of the benign SGTs overexpressed AR or HER-2. Coexpression of AR and HER-2 should not define SDC, but immunostaining should be considered in high grade salivary carcinomas, as some show overexpression and may benefit from targeted therapy.