Mucoepidermoid carcinoma (MEC) is historically defined by a mix of squamoid, intermediate, and mucous cells, but we have recently encountered several cases lacking immunoreactivity for squamous ...markers p40, p63, and CK5/6 despite MAML2 fusions. This study will characterise these unique tumours. Ten MEC were collected arising from the parotid gland (n = 4), submandibular gland (n = 2), nasopharynx (n = 1), base of tongue (n = 1), bronchus (n = 1), and trachea (n = 1). Six tumours were low‐grade, two intermediate‐grade, one high‐grade, and one demonstrated low‐grade areas with high‐grade transformation. Four cases were oncocytic, four had clear‐cell features, two had spindle cell features, and one high‐grade MEC had prominent solid, cord‐like, and micropapillary features. The tumours were negative for p40 (10/10), p63 (10/10), and CK5/6 (9/9). Targeted RNA sequencing demonstrated CRTC1::MAML2 in five cases, CRTC3::MAML2 in two, and a novel MAML2::CEP126 in the unusual high‐grade case. In two cases with insufficient RNA, MAML2 fluorescence in situ hybridisation (FISH) showed rearrangement. Genetically‐confirmed MEC may lack overt squamous differentiation by histology and immunohistochemistry. While most cases harboured canonical fusions and fit within the spectra of MEC variants with oncocytic, clear cell, and/or spindle cell features, one had a novel MAML2::CEP126 fusion and unusual morphology. In MEC without squamoid cells, the use of immunohistochemistry may hinder, rather than aid, the correct diagnosis. In such cases, MAML2 analysis is most useful. The historical definition of MEC as a carcinoma with squamoid, intermediate and mucous cells should be revisited.
Background
RNA sequencing of unclassified soft tissue tumors has allowed for definition of multiple new entities. Antonescu et al. recently reported three case of low grade sarcoma with recurrent
...EWSR1/FUS::NACC1
fusion and distinctive storiform architecture that were suggestive of a novel tumor type.
Methods
Here, we present a case of an additional sarcoma with
FUS::NACC1
fusion that arose in the head and neck and showed immunohistochemical evidence of epithelial differentiation.
Results
A 41 year old woman presented with throat and inner ear pain and was found to have a nasopharyngeal mass. Biopsy highlighted a spindle cell neoplasm composed of bland cells arranged in a tight storiform pattern. On immunohistochemistry, the tumor cells were focally positive for S100 in a fibrillary pattern but were also positive for high molecular weight cytokeratin, p40, and CD34. RNA sequencing demonstrated a
FUS::NACC1
fusion. The patient remains free of disease 2 years after surgical resection.
Conclusion
These findings confirm the previously-reported recurrent storiform histology in sarcomas with
EWSR1/FUS::NACC1
fusion while simultaneously expanding the immunohistochemical spectrum of this entity to include overt epithelial differentiation. With involvement of a head and neck mucosal site, these findings also expand the differential diagnosis to include multiple mesenchymal entities including spindle cell squamous cell carcinoma. Further recognition of this emerging entity via expanded RNA sequencing panels will be necessary to determine the prevalence of these unique features.
Objectives
To evaluate the performance characteristics of seven predetermined imaging features on pretreatment computed tomography (CT) in identifying extranodal extension (ENE) in cervical lymph ...node metastases from human papillomavirus‐positive oropharyngeal carcinoma (HPV‐OPC).
Study Design
Retrospective study.
Methods
Seventy‐three patients with HPV‐OPC who underwent primary surgery and cervical lymph node dissection were included. Preoperative contrast‐enhanced CT (cCT) imaging was evaluated by two radiologists blinded to pathological results. Each cCT was scored for seven imaging features of interest: 1) indistinct capsular contours, 2) irregular nodal margins, 3) perinodal fat stranding, 4) perinodal fat planes, 5) nodal necrosis, 6) intranodal cysts, and 7) nodal matting. Logistic regression was employed to determine radiologist‐specific odds ratios (OR) of predicting ENE for each imaging feature and radiologist‐specific receiver operating characteristics (sensitivity Sn, specificity Sp, area under the curve AUC, positive predictive value PPV, negative predictive value NPV) for each imaging feature.
Results
Thirty‐two (44%) patients had ENE‐positive lymph nodes. The presence of irregular margins (ORA = 12.3, 95% confidence interval CIA = 2.3–65.9; ORB = 7.0, 95% CIB = 1.4–36.3) and absence of perinodal fat plane (ORA = 6.8, 95% CIA = 2.0–23.3; ORB = 14.2, 95% CIB = 1.7–120.5) were significantly associated with ENE for each radiologist. Irregular nodal margin status was most specific for ENE (SnA = 45%, SpA = 94%, AUCA = 69%, PPVA = 82%, NPVA = 73%; SnB = 28%, SpB = 95%, AUCB = 61%, PPVB = 80%, NPVB = 64%). Absence of perinodal fat plane was most sensitive for ENE (SnA = 87%, SpA = 50%, AUCA = 69%, PPVA = 59%, NPVA = 62%; SnB = 96%, SpB = 34%, AUCB = 65%, PPVB = 53%, NPVB = 63%).
Conclusions
Of the seven imaging features hypothesized to be associated with ENE‐status, the presence of irregular nodal margins and absence of perinodal fat plane were the most specific and sensitive features, respectively.
Level of Evidence
4 Laryngoscope, 130:1479–1486, 2020
While P16 immunohistochemistry (IHC) is a well-established surrogate marker of Human Papillomavirus (HPV) in oropharyngeal squamous cell carcinoma (OSCC), Retinoblastoma 1 (RB1) loss may lead to p16 ...overexpression in the absence of HPV. We determined the proportion of p16-positive/HPV-negative OSCC with RB1 loss and other alterations in RB1/p16 pathway, and tested RB1 IHC as a prognostic biomarker for OSCC, along with the 8th edition of AJCC staging manual. P16 and RB1 IHC and HPV DNA in situ hybridization (ISH) were performed on 257 OSCC. High risk HPV RNA ISH,
RB1
fluorescence in situ hybridization (FISH), and next generation sequencing (NGS) were done on p16-positive/HPV DNA ISH-negative OSCC. Disease free survival (DFS) was used as an endpoint. In the entire cohort and in p16-positive (
n
= 184) and p16-negative (
n
= 73) subgroups, AJCC 8th edition staging correlated with DFS (
p
< 0.01). RB1 IHC showed RB1 loss in p16-positive OSCC only (79/184, 43%). RB1 loss by IHC is associated with a better DFS, without providing additional prognostic information for patients with p16-positive OSCC. HPV RNA ISH was positive in 12 of 14 HPV DNA ISH-negative cases. RB1 IHC showed loss in 10 of 15 HPV DNA ISH-negative cases and in 1 of 2 HPV RNA ISH-negative cases. Overall, only one case of p16-positive/HPV RNA ISH-negative OSCC showed RB1 loss by IHC (1/184, 0.5%). Of the 10 p16-positive and HPV DNA ISH-negative cases with RB1 loss by IHC, 2 had
RB1
hemizygous deletion and 3 showed Chromosome 13 monosomy by FISH. No
RB1
mutations were detected by NGS. Other molecular alterations in p16-positive/HPV DNA ISH-negative cases included
TP53
and
TERT
mutations and
DDX3X
loss. HPV-independent RB1 inactivation rarely results in false positive p16 IHC. RB1 inactivation by high risk HPV E7 oncoprotein may co-exist with
RB1
deletion. RB1 loss is a favorable prognosticator and occurs exclusively in p16-positive OSCC. The 8th edition of the AJCC staging manual satisfactorily predicts DFS of OSCC patients.
Intraductal carcinoma (IDC) is a salivary gland tumor currently believed to be analogous to breast ductal carcinoma in situ, consisting of a complex neoplastic epithelial proliferation surrounded by ...a continuous layer of myoepithelial cells presumed to be native and non-neoplastic. Recent molecular insights have shown that there are at least 3 different types of IDC: (1) intercalated duct-like, with frequent NCOA4-RET fusions; (2) apocrine, with multiple mutations similar to salivary duct carcinoma; and (3) mixed intercalated duct-like and apocrine with frequent RET fusions, especially TRIM27-RET. Recent observations (eg, IDC occurring in lymph nodes) have challenged the notion that the myoepithelial cells of IDC are non-neoplastic. Five IDCs with known RET fusions by RNA sequencing were retrieved from the authors' archives, including 4 intercalated duct-like IDCs with NCOA4-RET, and 1 mixed intercalated duct-like/apocrine IDC with TRIM27-RET. A panel of immunohistochemistry antibodies (S100 protein, p63 or p40, mammaglobin, smooth muscle actin, calponin, androgen receptor) was tested. To precisely localize RET split-positive cells, each case was subjected to sequential retrieval of whole-slide imaging data of hematoxylin and eosin (HE) staining, immunofluorescence staining for calponin, and fluorescence in situ hybridization (FISH) for RET. Because NCOA4-RET is an inversion difficult to visualize on conventional RET FISH, a novel 3-color FISH technique was utilized to demonstrate it clearly. In all 5 cases, the proliferative ducts were completely surrounded by a layer of myoepithelial cells that were positive for p63 or p40, smooth muscle actin, and calponin. Using combined HE, calponin immunofluorescence, and RET FISH imaging, the positive signals were unmistakably identified in both calponin-negative ductal cells and peripheral, calponin-positive myoepithelial cells in all 5 cases. Utilizing combined HE, calponin immunofluorescence, and RET FISH imaging, we demonstrated that IDCs with RET fusions harbored this alteration in both the ductal and myoepithelial cells. This is compelling evidence that the myoepithelial cells of IDC are not mere bystanders, but are rather a component of the neoplasm itself, similar to other biphasic salivary gland neoplasms like pleomorphic adenoma and epithelial-myoepithelial carcinoma. This finding raises questions about the appropriate terminology, classification, and staging of IDC.
Thyroid gland teratomas are rare tumors that span a wide clinicopathologic spectrum. Although benign and immature teratomas arise in infants and young children and generally have good outcomes, ...malignant teratomas affect adults and follow an aggressive course. This divergent behavior raises the possibility that benign/immature and malignant teratomas are separate entities rather than different grades of a single tumor. However, the histogenesis and molecular underpinnings of thyroid gland teratomas are poorly understood regardless of grade. In this study, we performed next-generation sequencing on 8 thyroid gland teratomas, including 4 malignant, 3 benign, and 1 immature. We identified DICER1 hotspot mutations in all 4 malignant cases (100%) but not in any benign/immature cases (0%). No clinically significant mutations in other genes were found in either group. We also performed immunohistochemistry to characterize the primitive components of malignant teratomas. Not only did all cases consistently contain immature neural elements (synaptophysin and INSM1 positive), but also spindled cells with rhabdomyoblastic differentiation (desmin and myogenin positive) and bland epithelial proliferations of thyroid follicular origin (TTF-1 and PAX8 positive). Although DICER1 mutations have previously been implicated in multinodular hyperplasia and well-differentiated thyroid carcinomas, these findings demonstrate the first recurrent role for DICER1 in primitive thyroid tumors. The combined neural, rhabdomyoblastic, and homologous epithelial elements highlighted in this series of malignant thyroid gland teratomas parallel the components of DICER1-mutated tumors in other organs. Overall, these molecular findings further expand the differences between benign/immature teratomas and malignant teratomas, supporting the classification of these tumors as separate entities.
Background
Salivary duct carcinoma with rhabdoid features (SDC-RF) is a recently-described salivary gland tumor that bears striking histologic similarity to lobular carcinoma of the breast. While ...this tumor has an apocrine phenotype that supports classification as a variant of SDC, it infrequently arises in association with conventional SDC. Furthermore, discohesive architecture can be seen in non-apocrine salivary carcinomas, raising the possibility that discohesive growth should define a separate entity. In this study, we aimed to perform comprehensive molecular profiling of SDC-RF to better understand its pathogenesis and classification.
Methods
We documented the clinicopathologic features of 9 cases of SDC-RF and performed immunostains including AR, GCDFP, and e-cadherin on all cases. We also performed targeted next generation sequencing (NGS) panels on 7 cases that had sufficient tissue available.
Results
The SDC-RF represented 8 men and 1 woman with a median age of 67 years (range 63–83 years) and included 6 parotid, 2 buccal, and 1 submandibular primary. All tumors were uniformly composed of discohesive cells with abundant eosinophilic cytoplasm; signet-ring cell features were seen in 2 cases. All tumors were also positive for AR (100%) and GCDFP (100%), and 7 tumors (78%) displayed lost or abnormal e-cadherin. NGS highlighted concomitant
PIK3CA
and
HRAS
mutations in 4 tumors, with additional cases harboring
TP53
,
PTEN
, and
AKT1
mutations. Furthermore,
CDH1
alterations were seen in 6 cases, including a novel
CDH1
::
CORO7
fusion. Among 5 patients with follow-up available, 3 (60%) developed local recurrence and widespread distant metastasis and died of disease at a median 20 months (range 10–48 months).
Conclusions
Overall, our findings confirm frequent
CDH1
mutations and e-cadherin inactivation in SDC-RF, similar to discohesive tumors from other sites. We also highlight an apocrine molecular profile similar to conventional SDC. However, occasional
AKT1
mutation and signet-ring features suggest SDC-RF may also be related to mucinous adenocarcinoma. As more salivary tumors with discohesive growth are identified, it may become clearer whether SDC-RF should remain in the SDC family or be recognized as a separate entity.
Sinonasal teratocarcinosarcoma (TCS) is a rare tumor defined by intermixed neuroepithelial, mesenchymal, and epithelial elements. While its etiology was historically ambiguous, we recently reported ...frequent SMARCA4 loss by immunohistochemistry, suggesting that TCS might be related to SMARCA4-deficient sinonasal carcinomas. However, other molecular alterations including CTNNB1 mutation have been reported in TCS, and its full genetic underpinnings are unclear. Here, we performed the first comprehensive molecular analysis of sinonasal TCS to better understand its pathogenesis and classification. We collected 30 TCS including 22 cases from our initial study. Immunohistochemical loss of SMARCA4 was seen in 22 cases (73%), with total loss in 18 cases (60%). β-catenin showed nuclear localization in 14 cases (64%) of the subset tested. We selected 17 TCS for next-generation sequencing with enrichment for partial or intact SMARCA4 immunoexpression. We identified inactivating SMARCA4 mutations in 11 cases (65%) and activating CTNNB1 mutations in 6 cases (35%), including 5 cases with both. Of 5 cases that lacked SMARCA4 or CTNNB1 mutation, 2 harbored other SWI/SNF complex and Wnt pathway alterations, including 1 with SMARCB1 inactivation and 1 with concomitant APC and ARID1A mutations, and 3 had other findings, including DICER1 hotspot mutation. These findings confirm that SMARCA4 inactivation is the dominant genetic event in sinonasal TCS with frequent simultaneous CTNNB1 mutations. They further underscore a possible relationship between TCS and sinonasal carcinomas with neuroendocrine/neuroectodermal differentiation. However, while SMARCA4 and β-catenin immunohistochemistry may help confirm a challenging diagnosis, TCS should not be regarded as a molecularly defined entity.
Objectives
In the larynx, differentiating squamous papillomas from de‐novo papillary squamous dysplasias or squamous cell carcinomas (SCC) has significant consequences for management. Overlapping ...clinical presentations and cytologic changes across the spectrum of papillary lesions presents diagnostic challenges for otolaryngologists and pathologists. In this study, we evaluate whether ribonucleic acid (RNA) in‐situ hybridization (ISH) for low‐risk and high‐risk human papillomavirus (HPV) can help distinguish these lesions.
Methods
We constructed tissue microarrays from 97 papillary laryngeal lesions, including 61 squamous papillomas, two papillomas with dysplasia, two SCCs‐ex papilloma, 14 papillary squamous dysplasias, and 18 papillary SCCs identified at the Johns Hopkins Hospital between 2000 and 2017. We performed RNA ISH using probes for low‐risk and high‐risk HPV types.
Results
Low‐risk HPV RNA was identified in 55 benign papillomas (90%), two papillomas with dysplasia (100%), and two SCCs‐ex papilloma (100%) but was absent in de‐novo papillary dysplasias and SCCs (0%). High‐risk HPV RNA ISH was positive only in four papillary SCC (22%). Overall, low‐risk HPV RNA ISH was 90% sensitive and 89% specific for benign papillomas with a positive predictive value of 93% and negative predictive value of 84%. In contrast, high‐risk HPV was 20% sensitive for SCC.
Conclusion
Low‐risk HPV RNA ISH is a useful diagnostic adjunct for distinguishing laryngeal squamous papillomas from papillary squamous dysplasia and SCC. However, it is not entirely specific for benign processes as it is also retained in papillomas with dysplasia and SCCs‐ex papilloma. Because high‐risk HPV is rare in papillary laryngeal lesions, high‐risk HPV RNA ISH has limited utility.
Level of Evidence
Level 4
Laryngoscope, 130:955–960, 2020
The role of human papillomavirus (HPV) as an etiologic and transformational agent in inverted Schneiderian papilloma (ISP) is unclear. Indeed, reported detection rates of HPV in ISPs range from 0 to ...100%. The true incidence has been confounded by a tendency to conflate high- and low-risk HPV types and by the inability to discern biologically relevant from irrelevant HPV infections. The recent development of RNA in situ hybridization for high-risk HPV E6/E7 mRNA now allows the direct visualization of transcriptionally active high-risk HPV in ISP, providing an opportunity to more definitively assess its role in the development and progression of ISPs. We performed p16 immunohistochemistry and high-risk HPV RNA in situ hybridization on 30 benign ISPs, 7 ISPs with dysplasia, 16 ISPs with carcinomatous transformation, and 7 non-keratinizing squamous cell carcinomas (SCCs) with inverted growth that were unassociated with ISP. Transcriptionally active HPV was not detected in any of the 52 ISPs including those that had undergone carcinomatous transformation, but it was detected in two of seven (29%) non-keratinizing SCCs that showed inverted growth. There was a strong correlation between high-risk HPV RNA in situ hybridization and p16 immunohistochemistry (97%; p < 0.01). These results indicate that transcriptionally active high-risk HPV does not play a common role in either the development of ISP or in its transformation into carcinoma.
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