Biphenotypic sinonasal sarcoma (BSNS) is a recently recognized low-grade sarcoma that exhibits both neural and myogenic differentiation. This unique dual phenotype stems from recurrent rearrangements ...in PAX3 , a transcription factor that promotes commitment along both lineages. While identification of PAX3 rearrangements by fluorescence in situ hybridization (FISH) can confirm a BSNS diagnosis, this assay is not widely available. This study evaluates whether an expanded immunohistochemical panel can facilitate recognition of BSNS without molecular analysis. Eleven cases of BSNS were identified from the surgical pathology archives of two academic medical centers. In 8 cases, the diagnosis was confirmed by FISH using custom probes for PAX3. In 3 cases FISH failed but histologic and immunophenotypic findings were diagnostic for BSNS. All 11 BSNS (100%) were at least focally positive for S100 as well as calponin and/or smooth muscle actin. In addition, 10 of 11 (91%) expressed nuclear β-catenin, 8 of 10 (80%) expressed factor XIIIa, 4 of 11 (36%) expressed desmin, and 3 of 10 (30%) expressed myogenin. All 11 tumors were negative for SOX10. While no single marker resolves immunohistochemical overlap between BSNS and its histologic mimickers such as nerve sheath tumors, an extended immunohistochemical panel that includes β-catenin and SOX10 helps to support the diagnosis of BSNS without the need for gene rearrangement studies.
Summary Mammary analogue secretory carcinoma is a recently described salivary gland neoplasm defined by ETV6-NTRK3 gene fusion. Mammary analogue secretory carcinoma's morphology is not entirely ...specific and overlaps with other salivary gland tumors. Documenting ETV6 rearrangement is confirmatory, but most laboratories are not equipped to perform this test. As mammary analogue secretory carcinomas are positive for mammaglobin, immunohistochemistry could potentially replace molecular testing as a confirmatory test, but the specificity of mammaglobin has not been evaluated across a large and diverse group of salivary gland tumors. One hundred thirty-one salivary gland neoplasms were evaluated by routine microscopy, mammaglobin immunohistochemistry, and ETV6 break-apart fluorescent in situ hybridization. The cases included 15 mammary analogue secretory carcinomas, 44 adenoid cystic carcinomas, 33 pleomorphic adenomas, 18 mucoepidermoid carcinomas, 10 acinic cell carcinomas, 4 adenocarcinomas not otherwise specified, 3 polymorphous low-grade adenocarcinomas, 3 salivary duct carcinomas, and 1 low-grade cribriform cystadenocarcinoma. All 15 mammary analogue secretory carcinomas harbored the ETV6 translocation and were strongly mammaglobin positive. None of the 116 other tumors carried the ETV6 translocation; however, mammaglobin staining was present in 1 (100%) of 1 low-grade cribriform cystadenocarcinoma, 2 (67%) of 3 polymorphous low-grade adenocarcinomas, 2 (67%) of 3 salivary duct carcinomas, 2 (11%) of 18 mucoepidermoid carcinomas, and 2 (6%) of 33 pleomorphic adenomas. Mammaglobin is highly sensitive for mammary analogue secretory carcinoma, but immunostaining can occur in a variety of tumors that do not harbor the ETV6 translocation. Strategic use of mammaglobin immunostaining has a role in the differential diagnosis of salivary gland neoplasms, but it should not be indiscriminately used as a confirmatory test for mammary analogue secretory carcinoma.
Summary Anaplastic thyroid carcinoma can be difficult to diagnose because it does not show thyroid differentiation morphologically or immunohistochemically. Depending on the histologic variant, ...anaplastic thyroid carcinoma may be confused with sarcoma or squamous cell carcinoma of the head and neck. PAX8 is a transcription factor expressed in normal and neoplastic thyroid follicular epithelium and only a few other tissues. This restricted expression suggests that PAX8 staining could be useful when dealing with spindled or squamoid tumors of the neck. The purposes of this study were to determine the frequency of PAX8 staining in anaplastic thyroid carcinoma and to evaluate PAX8 immunohistochemistry as a means of distinguishing its squamoid variant from head and neck squamous cell carcinoma. PAX8 immunohistochemical staining was performed on 34 anaplastic thyroid carcinomas and 118 head and neck squamous cell carcinomas. PAX8 staining was present in 26 (76%) anaplastic thyroid carcinomas including 16 (100%) of 16 squamoid variants, 7 (58%) of 12 giant cell/pleomorphic variants, and 3 (50%) of 6 spindled variants. All head and neck squamous cell carcinomas were negative for PAX8. PAX8 expression is often retained in anaplastic thyroid carcinomas including the squamoid variant, but it is not expressed in head and neck squamous cancers. PAX8 staining is an excellent marker for carcinomas of follicular epithelial origin, including those carcinomas that are undifferentiated in other respects. The tissue specificity of PAX8 expression may be useful in resolving the differential diagnosis of anaplastic thyroid carcinoma such as the distinction between its squamoid variant and squamous cell carcinoma of the head and neck.
Abstract A subset of head and neck squamous cell carcinomas are caused by the human papillomavirus (HPV). This HPV-related form of head and neck squamous cell carcinoma (HPV-HNSCC) has captured the ...attention of the oncology community for its rising incidence, its link to non-traditional risk factors, and its divergent clinical behavior. To diagnose this special form of head and neck squamous cell carcinoma is to provide important prognostic information and, in some instances, redirect clinical therapy. The diagnosis of HPV-HNSCC is aided by a strong appreciation for its characteristic microscopic findings and by an awareness of aberrant features that set apart a growing list of HPV-HNSCC morphologic variants. This review will delineate the microscopic appearance of HPV-HNSCC, spotlight ways in which the misinterpretation of these microscopic features can lead to diagnostic confusion, offer recommendations for appropriate terminology when diagnosing HPV-HNSCC, and provide examples of specific diagnostic scenarios where HPV testing can inform the diagnostic process.
Summary Adenoid cystic carcinoma (ACC) is a basaloid tumor consisting of myoepithelial and ductal cells typically arranged in a cribriform pattern. Adenoid cystic carcinoma is generally regarded as a ...form of salivary gland carcinoma, but it can arise from sites unassociated with salivary tissue. A rare form of prostate carcinoma exhibits ACC-like features; it is no longer regarded as a true ACC but rather as prostatic basal cell carcinoma (PBCC) and within the spectrum of basaloid prostatic proliferations. True ACCs often harbor MYB translocations resulting in the MYB-NFIB fusion protein. MYB analysis could clarify the true nature of prostatic carcinomas that exhibit ACC features and thus help refine the classification of prostatic basaloid proliferations. Twelve PBCCs were identified from the pathology consultation files of Johns Hopkins Hospital. The histopathologic features were reviewed, and break-apart fluorescence in situ hybridization for MYB was performed. All 12 cases exhibited prominent basaloid histology. Four were purely solid, 7 exhibited a cribriform pattern reminiscent of salivary ACC, and 1 had a mixed pattern. The MYB rearrangement was detected in 2 (29%) of 7 ACC-like carcinomas but in none (0%) of the 5 PBCCs with a prominent solid pattern. True ACCs can arise in the prostate as is evidenced by the presence of the characteristic MYB rearrangement. When dealing with malignant basaloid proliferations in the prostate, recommendations to consolidate ACCs with other tumor types may need to be reassessed, particularly in light of the rapidly advancing field of biologic therapy where the identification of tumor-specific genetic alterations presents novel therapeutic targets.
The Atlas of Thyroid Cytopathology is a generously illustrated and user-friendly volume that serves as a desk reference and a practical guide in the diagnostically challenging area of thyroid ...cytopathology. The text is comprised of 500 high-resolution color images that thoroughly illustrate the important aspects of the cytopathology of thyroid disease. Complete coverage of thyroid cytopathology is provided; in addition to full coverage of non-neoplastic lesions, benign and borderline neoplasms and papillary thyroid carcinoma, chapters include normal cytology, uncommon primary neoplasms, follicular neoplasms, H? cell neoplasms, medullary thyroid carcinomas, and metastatic and secondary cancers. Selected images of the histopathologic characteristics of the lesions are also included for morphologic correlation, making this text attractive to both cytopathologists and surgical pathologists. Nationally recognized experts in thyroid cytopathology and histopathology provide authoritative analysis of every aspect of thyroid cytopathologic analysis.
Summary Metastatic cystic squamous cell carcinomas of the neck often harbor human papillomavirus 16 and, in turn, overexpress p16. P16 immunohistochemistry could be useful in the evaluation of ...patients who present with cystic squamous lesions of the neck, particularly when the distinction between a benign lymphoepithelial cyst and a metastatic squamous cell carcinoma cannot be easily resolved on clinical or pathologic grounds. Implementation of this strategy, however, awaits a description of p16 expression in benign lymphoepithelial cysts. The purpose of this study was to evaluate p16 staining in cystic squamous lesions of the neck with an emphasis on benign lymphoepithelial cysts. P16 immunohistochemistry was performed on tissue sections and fine needle aspirates of benign (n = 49) and malignant (n = 16) squamous lesions of the neck. P16-positive cases were further evaluated by human papillomavirus 16 in situ hybridization. P16 staining was seen in the tissue sections of 16 of 37 (43%) benign lymphoepithelial cysts. P16 staining tended to localize to regions of the squamous epithelium penetrated by interdigitating lymphocytes. In the aspirates, p16 staining was noted in 5 of 12 (42%) benign lymphoepithelial cysts and in 3 of 16 (19%) cystic squamous cell carcinomas. Human papillomavirus 16 was detected in the 3 p16-positive cystic squamous cell carcinomas but in none of the p16-positive benign lymphoepithelial cysts. P16 overexpression is not always linked to high-risk human papillomavirus integration, but may be intrinsic to the reticulated epithelium that lines benign lymphoepithelial cysts. This observation limits the role of p16 staining as a surrogate marker of human papillomavirus 16 infection and as a diagnostic tool in separating benign from malignant cystic squamous lesions of the neck.
The confirmation of human papillomavirus (HPV) as a causative agent for a subset of squamous cell carcinomas of the head and neck has resulted in a growing expectation for HPV testing in head and ...neck cancers. An increasing understanding of HPV-related tumorigenesis has informed this evaluation process in a manner that is moving wide scale, indiscriminant, and nonstandardized testing toward a more directed, clinically relevant, and standardized approach. This review addresses the current state of HPV detection and focuses on the importance, appropriate time, and need for HPV testing.
IgG4-related disease has been recently defined as a distinct clinic-pathologic entity, characterized by dense IgG-4 plasmacytic infiltration of diverse organs, fibrosis, and tumefactive lesions. ...Salivary and lacrimal glands are a target of this disease and, when affected, may clinically resemble Küttner tumor, Mikulicz disease, or orbital inflammatory pseudotumor. In some patients, the disease is systemic, with metachronous involvement of multiple organs, including the pancreas, aorta, kidneys, and biliary tract. We report a 66-year-old man who presented with salivary gland enlargement and severe salivary hypofunction and was diagnosed with IgG4-related disease on the basis of a labial salivary gland biopsy. Additional features of his illness included a marked peripheral eosinophilia, obstructive pulmonary disease, and lymphoplasmacytic aortitis. He was evaluated in the context of a research registry for Sjögren syndrome and was the only 1 of 2594 registrants with minor salivary gland histopathologic findings supportive of this diagnosis.
Summary Neuropilin-2, a cell surface receptor involved in angiogenesis and axonal guidance, has recently been shown to be a critical mediator of tumor-associated lymphangiogenesis. Given that ...lymphangiogenesis is a major conduit of metastasis in melanomas and that blocking neuropilin-2 function in vivo is effective in inhibiting tumor cell metastasis, we sought to determine the clinical relevance of neuropilin-2 expression in cutaneous melanoma. Immunohistochemical analysis of neuropilin-2 expression was evaluated in nevomelanocytic proliferations that included a tissue microarray and histologic sections from samples of primary melanomas (n = 42; 40 for tissue microarray, 2 for histologic sections), metastatic melanomas (n = 30; 22 for tissue microarray, 8 for histologic sections), and nevi (n = 30; 5 for tissue microarray, 25 for histologic sections), as well as a panel of normal human tissues and select nonmelanocytic tumors. Staining for grading and intensity of neuropilin-2 expression was estimated semiquantitatively as follows for the former: less than 20%, 20% to 60%, and more than 60% of tissue present, and for the latter from 0 to 3, with 3 being the highest and 0 the lowest intensity. In nevomelanocytic proliferations, more than 20% staining for neuropilin-2 was noted in 36 (86%) of 42 cases of primary melanoma, in 27 (90%) of 30 cases of metastatic melanoma, and in 9 (30%) of 30 cases of nevi with differences achieving statistical significance between melanoma (primary and metastatic) and nevi ( P < .0001). For staining intensity, an intensity of 2 or more was noted in 36 (86%) of 42 cases of primary melanoma, in 17 (57%) of 30 cases of metastatic melanoma and in 7 (30%) of 23 cases of nevi, with differences achieving statistical significance between melanoma (primary and metastatic) and nevi ( P < .0001). In normal human tissue, consistently strong neuropilin-2 staining was noted in kidney (glomerular endothelial cells, collecting tubules, and collecting ducts), skin (epidermal keratinocytes), and testes (epithelium of the seminiferous tubules), whereas in tumoral tissue, consistently strong staining was noted only in renal cell carcinoma but not in any of the other tumors studied. More recently, using a heterotypic coculture methodology with melanoma and endothelial cells, we have demonstrated successful up-regulation of neuropilin-2 and confirmed the critical role of neuropilin-2 in melanoma-endothelial interactions. Because these coculture methods were developed to model melanoma metastasis, the significantly increased and enhanced expression of neuropilin-2 staining in primary and metastatic melanoma versus nevi in the current study suggests that it is also relevant in vivo.
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