Adenoid cystic carcinoma of the salivary glands: an immunohistochemical analysis

Activating IGF1R hotspot non-frameshift insertions define a novel, potentially targetable molecular subtype of adenoid cystic carcinoma

Activation of the tyrosine kinase receptor IGF1R is targetable with existing tyrosine kinase inhibitors (TKIs) and monoclonal antibodies, but mutations in IGF1R have not been systematically characterized. Pan-cancer analysis of 326,911 tumors identified two distinct, activating non-frameshift insertion hotspots in IGF1R, which were significantly enriched in adenoid cystic carcinomas (ACCs). IGF1R alterations from 326,911 subjects were analyzed by variant effect prediction class, position within the gene, and cancer type. 6502 (2.0%) samples harbored one or more alterations in IGF1R. Two regions were enriched for non-frameshift insertions: codons 663-666 at the hinge region of the fibronectin type 3 domain and codons 1034-1049 in the tyrosine kinase domain. Hotspot insertions were highly enriched in ACCs (27.3-fold higher than in the remainder of the pan-cancer dataset; P = 2.3 × 10^-17). Among salivary gland tumors, IGF1R hotspot insertions were entirely specific to ACCs. IGF1R alterations were most often mutually exclusive with other ACC drivers (9/15, 60%). Tumors with non-frameshift hotspot IGF1R insertions represent a novel, potentially targetable subtype of ACC. Additional studies are needed to determine whether these patients respond to existing IGF1R inhibitors.

Positron emission tomography and magnetic resonance imaging in primary central nervous system lymphoma-a narrative review

This review addresses the challenges of primary central nervous system (CNS) lymphoma diagnosis, assessment of treatment response, and detection of recurrence. Primary CNS lymphoma is a rare form of extra-nodal non-Hodgkin lymphoma that can involve brain, spinal cord, leptomeninges, and eyes. Primary CNS lymphoma lesions are most commonly confined to the white matter or deep cerebral structures such as basal ganglia and deep periventricular regions. Contrast-enhanced magnetic resonance imaging (MRI) is the standard diagnostic modality employed by neuro-oncologists. MRI often shows common morphological features such as a single or multiple uniformly well-enhancing lesions without necrosis but with moderate surrounding edema. Other brain tumors or inflammatory processes can show similar radiological patterns, making differential diagnosis difficult. [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) has selected utility in cerebral lymphoma, especially in diagnosis. Primary CNS lymphoma can sometimes present with atypical findings on MRI and FDG PET, such as disseminated disease, non-enhancing or ring-like enhancing lesions. The complementary strengths of PET and MRI have led to the development of combined PET-MR systems, which in some cases may improve lesion characterization and detection. By highlighting active developments in this field, including advanced MRI sequences, novel radiotracers, and potential imaging biomarkers, we aim to spur interest in sophisticated imaging approaches.

Basaloid squamous cell carcinoma

Basaloid squamous cell carcinoma (BSCC) is a rare variant of squamous cell carcinoma characterized by a conglomerate of clinically aggressive course and disparate histopathological features. It is frequently seen in upper aerodigestive tract area. Histopathologically, it is biphasic and composed of two types of tumor cells, namely basaloid and squamous cells. Tumor markers, namely, BerEp4, epithelial membrane antigen and p53 are used in this case to differentiate from similar tumors which impersonate BSCC histologically but differ prognostically. We report a case of BSCC in a 48-year-old female patient, involving the lateral border of the tongue with an exhaustive picture of its histological and immunohistochemical appearance.

Matrix metalloproteinase-7, -8, -9, -15, and -25 in minor salivary gland adenoid cystic carcinoma

Knowledge on the role of matrix metalloproteinases (MMPs) in adenoid cystic carcinoma (ACC) is limited. MMPs are capable of degrading almost all extracellular and pericellular components to promote invasion and metastasis. This study aimed to evaluate the immunohistochemical expression of MMP-7, -8, -9, -15, and -25 in ACC and to relate the results with clinicopathological factors and survival. The study included 68 patients with minor salivary gland ACC treated at the Helsinki University Hospital (Helsinki, Finland) in 1974-2012. Samples from 52 patients were available, consisting of 44 primary tumours and eight recurrent tumours. We scored immunostaining of MMP-7, -8, -9, -15, and -25 and analysed the immunoscore against clinical and pathological parameters using statistical correlation test. MMP-9 immunoexpression in pseudocysts of ACC and in peritumoural inflammatory cells associated with better survival and fewer treatment failures. High tumoural MMP-7 and -25 associated with better survival. High tumoural MMP-15 associated with poorer survival and high tumoural MMP-9 with advanced stage and regional recurrences. Tumour cells did not show MMP-8 immunopositivity. These results suggest that MMP-9 may contribute to ACC carcinogenesis in different roles. MMP-7, -8, and -9 can stimulate signalling pathways that may promote tissue modulation and metastatic potential. MMP-15 and -25 may reflect prognosis.

Adenoid Cystic Carcinoma of Salivary Gland: A Ten-Year Single Institute Experience

Adenoid cystic carcinoma is a rare tumor, accounting for about 7.5% of all salivary gland neoplasms. More frequent developing in minor salivary gland, this is a slow-growing tumor with a long-lasting natural evolution, quite aggressive locally, but which has a tendency toward local recurrence and even for distant metastasis. We conducted a retrospective study limited to a period of 10 years in a single medical institution to investigate the morphoclinical profile of this tumor. Thus, we have established that about 60% of the tumors developed in men, with near 40% of the cases in patients in the sixth decade and, most common, the pathology affected the parotid and minor salivary glands from the hard palate mucosa. Histopathologically, prevailed the solid variant, with 72% cases presenting perineural invasion, and 41% cases showing positive surgical resection margins. Most cases had a long-standing asymptomatic evolution, so that at the time of diagnosis, more than two thirds of the patients were at least in stage II-pTNM, and in one-fifth of the cases histopathology showed lymph nodes disseminations.

Submucosal gland neoplasms of the esophagus: an update and review

Submucosal glands (SMGs) present throughout human esophagus with clusters at either the upper third or lower third of the organ. SMGs tend to atrophy with age, and neoplasms arising in these glands are rare. In order to bring convenience to diagnosis, we summarize the histopathologic characteristics of all esophageal submucosal gland tumors (SGTs). Due to the morphological similarity, the nomenclature of salivary tumors is adopted for SGTs. However, there is great confusion about the definition and histogenesis of these tumors, especially the malignant subtypes. In the literature, esophageal mucoepidermoid carcinoma and adenoid cystic carcinoma usually adjoin the surface squamous epithelium and coexist with intraepithelial neoplasia or invasive squamous cell carcinoma (SCC). In addition, the typical gene alterations of salivary tumors have not been reported in these SGTs. Therefore, we propose to apply stringent diagnostic criteria to esophageal SGTs so as to exclude mimickers that are SCCs with various degree of SMG differentiation.

SOX10 Is a Sensitive Marker for Breast and Salivary Gland Adenoid Cystic Carcinoma: Immunohistochemical Characterization of Adenoid Cystic Carcinomas

Breast adenoid cystic carcinomas (AdCCs) can pose diagnostic difficulty due to their rarity, particularly on limited biopsy material. Given that these tumors are triple-negative breast cancers with favorable prognosis, accurate diagnosis is critical for clinical management. A total of 12 cases of breast AdCCs were studied; 17 age-matched salivary gland AdCCs and 5 metastatic AdCCs (1 breast and 4 salivary gland primaries) were also examined. Immunohistochemical stains for SOX10, Ki-67, c-KIT, β-catenin, epithelial membrane antigen (EMA), p63, cytokeratin 7 (CK7), cytokeratin 5/6 (CK5/6), and androgen receptor (AR) were performed. All breast (100%) and metastatic (100%) AdCCs and all but 2 salivary gland AdCCs showed diffuse nuclear staining (>50% of cells) for SOX10. Epithelial membrane antigen showed lowest expression in breast AdCCs and the highest expression in metastatic AdCCs (P < .01). Except one case of salivary gland AdCC that showed loss of β-catenin expression and developed subsequent metastasis, all AdCCs showed strong and diffuse membranous β-catenin expression. There were no significant differences in expression of CK7, p63, CK5/6, AR, Ki-67, and c-KIT (P > .05) among breast, salivary gland, and metastatic AdCCs. We investigated the immunophenotypic features of breast AdCCs in comparison with salivary gland and metastatic AdCCs. Despite the contrast in prognosis, these tumors are immunophenotypically similar. SOX10 is a sensitive diagnostic marker in all AdCCs, which could potentially aid in diagnosis of these tumors on limited material.

Clinical and molecular insights into adenoid cystic carcinoma: Neural crest-like stemness as a target

OBJECTIVES

This review surveys trialed therapies and molecular defects in adenoid cystic carcinoma (ACC), with an emphasis on neural crest-like stemness characteristics of newly discovered cancer stem cells (CSCs) and therapies that may target these CSCs.

DATA SOURCES

Articles available on Pubmed or OVID MEDLINE databases and unpublished data.

REVIEW METHODS

Systematic review of articles pertaining to ACC and neural crest-like stem cells.

RESULTS

Adenoid cystic carcinoma of the salivary gland is a slowly growing but relentless cancer that is prone to nerve invasion and metastases. A lack of understanding of molecular etiology and absence of targetable drivers has limited therapy for patients with ACC to surgery and radiation. Currently, no curative treatments are available for patients with metastatic disease, which highlights the need for effective new therapies. Research in this area has been inhibited by the lack of validated cell lines and a paucity of clinically useful markers. The ACC research environment has recently improved, thanks to the introduction of novel tools, technologies, approaches, and models. Improved understanding of ACC suggests that neural crest-like stemness is a major target in this rare tumor. New cell culture techniques and patient-derived xenografts provide tools for preclinical testing.

CONCLUSION

Preclinical research has not identified effective targets in ACC, as confirmed by the large number of failed clinical trials. New molecular data suggest that drivers of neural crest-like stemness may be required for maintenance of ACC; as such, CSCs are a target for therapy of ACC.

Characteristic Formation of Hyaluronan-Cartilage Link Protein-Proteoglycan Complex in Salivary Gland Tumors

Hyaluronan (HA) and its binding molecules, cartilage link protein (LP) and proteoglycan (PG), are structural components of the hydrated extracellular matrix. Because these molecules play important roles in the tumor microenvironment, we examined the distribution of HA, LP, versican, and aggrecan in salivary gland tumors using histochemical and immunohistochemical methods, including double staining. LP was present in pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC) tissues, and aggrecan was absent in the malignant tumors that we investigated. LP colocalized with both HA and aggrecan in the chondromyxoid matrix of PA, suggesting the presence of a HA-LP-aggrecan complex. Furthermore, the HA-LP-versican complex could be observed in the pseudocystic space of the cribriform structures in ACC. The characteristic HA-LP-PG complex in PA and ACC might play a role in the behavior of tumors, and immunohistochemical analysis of these molecules could represent a diagnostic adjunct for salivary gland tumors.

Adenoid cystic carcinoma of the head and neck--An update

This article provides an update on the current understanding of adenoid cystic carcinoma of the head and neck, including a review of its epidemiology, clinical behavior, pathology, molecular biology, diagnostic workup, treatment and prognosis. Adenoid cystic carcinoma is an uncommon salivary gland tumor that may arise in a wide variety of anatomical sites in the head and neck, often with an advanced stage at diagnosis. The clinical course is characterized by very late recurrences; consequently, clinical follow-up should extend at least >15 years. The optimal treatment is generally considered to be surgery with postoperative radiotherapy to optimize local disease control. Much effort has been invested into understanding the tumor's molecular biological processes, aiming to identify patients at high risk of recurrence, in hopes that they could benefit from other, still unproven treatment modalities such as chemotherapy or biological therapy.

Mammaglobin and S-100 immunoreactivity in salivary gland carcinomas other than mammary analogue secretory carcinoma

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumor that has morphologic features similar to secretory carcinoma of the breast and that also harbors the same ETV6 translocation. Diffuse mammaglobin and S-100 immunoreactivity are used to differentiate MASC from its morphologic mimics, especially acinic cell carcinoma and adenocarcinoma, not otherwise specified. However, the combination of mammaglobin and S-100 immunoreactivity has not been well studied in other types of salivary gland carcinomas that may have focal areas reminiscent of MASC. Here we evaluated mammaglobin and S-100 immunoreactivity in 15 cases each of polymorphous low-grade adenocarcinoma, adenoid cystic carcinoma and mucoepidermoid carcinoma, and also in 2 cases of adenocarcinoma, not otherwise specified, and 1 mucinous adenocarcinoma. Cases with significant co-expression of mammaglobin and S-100 (moderate or strong immunoreactivity in >25% of tumor cells) were further analyzed by fluorescence in situ hybridization using the ETV6 (12p13) break-apart probe. Nine cases (60%) of polymorphous low-grade adenocarcinoma and two (13.3%) of adenoid cystic carcinoma met the criteria for significant co-expression of mammaglobin and S-100. All were negative for the ETV6 translocation by fluorescence in situ hybridization. Although mammaglobin and S-100 positivity was seen in the majority of polymorphous low-grade adenocarcinomas and a minority of adenoid cystic carcinomas, none were positive for the ETV6 translocation characteristic of MASC. This indicates a need for caution in the use of immunohistochemistry for diagnosing MASC, especially in the absence of cytogenetic confirmation.

Adenoid cystic carcinoma: clinical and molecular features

The clinical features and common molecular alterations of adenoid cystic carcinoma (ACC) are reviewed in this paper. ACC is an uncommon neoplasm that most frequently arises in salivary glands and related tissue in the head and neck region. ACC has distinct histologic features, with cribriform and tubular growth patterns of basaloid cells displaying a predominantly myoepithelial cellular phenotype. This neoplasm also has uncommon clinical features of rare regional lymph node metastasis and a prolonged but relentlessly progressive clinical course. Clinical outcome in ACC is correlated to histologic grade, which is correlated to the degree of aneuploidy and genetic alterations present in the tumor genomes. Recent studies have identified that the majority of ACC contain alterations of the MYB gene, usually resulting in a fusion gene product with the NFIB gene by a t(6;9) translocation event. The molecular consequences of this alteration are incompletely understood, as are secondary molecular alterations that contribute to the neoplastic phenotype of ACC.

Adenoid cystic carcinoma: a rare clinical entity and literature review

The adenoid cystic carcinoma is a relatively rare epithelial tumor of the major and minor salivary glands, accounting for about 1% of all malignant tumor of the oral and maxillofacial region. Although it presents a widespread age distribution, peak incidence occurs predominantly among women, between the 5th and 6th decades of life. The clinical and pathological findings typical of this tumor include slow growth, perineural invasion, potential local recurrence and distant metastasis. Histopathologically it is composed of basaloid cells with primarily myoepithelial/basal cell differentiation. It presents three patterns, cribriform, tubular and solid; the solid type is related to a poor prognosis contrary to the cribriform type, which has a better prognosis. Surgical excision with wide margins is the treatment of choice, if it metastasizes to lymph nodules, post surgical radiotherapy is recommended. We presented herein the case of a 45 year old female patient who presented a palatal lesion, which was treated with surgery and radiotherapy as an additional treatment. We also described a brief literature review of adenoid cystic carcinoma.

Hierarchical cluster analysis of myoepithelial/basal cell markers in adenoid cystic carcinoma and polymorphous low-grade adenocarcinoma

Distinguishing adenoid cystic carcinoma from polymorphous low-grade adenocarcinoma of the salivary glands is important for their management. We studied the expression of several myoepithelial and basal/stem cell markers (smooth muscle actin, calponin, smooth muscle myosin heavy chain, metallothionein, maspin, and p63) by immunohistochemistry in 23 adenoid cystic carcinoma and 24 polymorphous low-grade adenocarcinoma, to identify the most useful marker or combination of markers that may help their diagnoses. The results were analyzed using hierarchical cluster analysis and chi(2) test for trend. We noted diffuse expression of smooth muscle actin in 20 adenoid cystic carcinoma vs one polymorphous low-grade adenocarcinoma (P<0.0001), calponin in 15 adenoid cystic carcinoma vs one polymorphous low-grade adenocarcinoma (P<0.0001), smooth muscle myosin heavy chain in 15 adenoid cystic carcinoma vs one polymorphous low-grade adenocarcinoma (P=0.001), metallothionein in 22 adenoid cystic carcinoma vs eight polymorphous low-grade adenocarcinoma (P<0.001), maspin in 22 adenoid cystic carcinoma vs 14 polymorphous low-grade adenocarcinoma, and p63 in 21 adenoid cystic carcinoma vs 14 polymorphous low-grade adenocarcinoma. Hierarchical clustering of smooth muscle actin, calponin, smooth muscle myosin heavy chain, and metallothionein was virtually identical (kappa< or =0.0035), suggesting no significant advantage to their use in combination than individually. Diffuse smooth muscle actin expression showed the highest accuracy (91.5%) and positive predictive value (95.2%) for adenoid cystic carcinoma. Thus, diffuse expression of smooth muscle actin, calponin, smooth muscle myosin heavy chain, and metallothionein was highly predictive of adenoid cystic carcinoma, whereas maspin and p63 were frequently expressed in both tumors. In differentiating adenoid cystic carcinoma from polymorphous low-grade adenocarcinoma, smooth muscle actin as a single ancillary test in support of the histological findings, appears to be as efficient as multiple immunohistochemical tests.

Selective Immunohistochemical Comparison of Polymorphous Low-Grade Adenocarcinoma and Adenoid Cystic Carcinoma

PURPOSE

Polymorphous low-grade adenocarcinoma (PLGA) is a salivary gland malignancy characterized by indolent growth and a low rate of metastasis. PLGA shares histological features with adenoid cystic carcinoma (ACC), including infiltrating solid and cribriform patterns, presence of cystic spaces, and neurotropism. The degree of polymorphism of PLGA presents diagnostic challenges, particularly in small biopsy specimens. Immunohistochemical reactions to differentiate PLGA from the more aggressive ACC would be extremely valuable but controversy exists in the current literature regarding their utility. This study examines the potential use of c-kit, Ki-67, smooth muscle actin (SMA), and muscle-specific actin (MSA) as ancillary markers for distinguishing PLGA from ACC.

PATIENTS AND METHODS

Medical records of 20 cases of PLGA treated at the Massachusetts General Hospital were reviewed. Patient demographic data and tumor-specific information were elicited. Formalin-fixed paraffin-embedded sections from 10 of these cases and 12 comparison cases of ACC were accessed. The histologic diagnoses were confirmed and immunohistochemical staining using antibodies to c-kit, Ki-67, SMA, and MSA was employed to determine differences in staining.

RESULTS

PLGA showed a significantly weaker immunohistochemical expression of c-kit compared with ACC (P = < .001). Ki-67, correlating with proliferative behavior, was more weakly expressed in PLGA (P = .091). The exuberant myoepithelial component of ACC resulted in stronger staining with SMA and MSA (P = .047; P = .065, respectively).

CONCLUSIONS

Statistically significant immunohistochemical staining patterns using c-kit and SMA in this study support their potential use as markers to differentiate PLGA from ACC in cases where the diagnosis can be challenging.

Adenoid cystic carcinoma and polymorphous low-grade adenocarcinoma of minor salivary glands: a comparative immunohistochemical study using the epithelial membrane and carcinoembryonic antibodies

OBJECTIVE

The purpose of this study was to investigate immunohistochemically the expression of epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA) in adenoid cystic carcinoma (AdCC) and polymorphous low-grade adenocarcinoma (PLGA) in an attempt to assess the ability of these markers to distinguish AdCC from PLGA when the histological features on routine hematoxylin and eosin are equivocal.

MATERIALS AND METHODS

Fourteen specimens of AdCC, 10 PLGA, and five normal minor salivary glands fixed in 10% formalin and embedded in paraffin, were retrieved from the files of our department and were retrospectively studied with the streptavidin-biotin complex method using the epithelial membrane and carcinoembryonic antibodies.

RESULTS

The immunoreactivities and the expression patterns of EMA and CEA in AdCC and PLGA were similar.

CONCLUSIONS

The results of this study suggest that the immunostaining of AdCC and PLGA with EMA and CEA could not offer an adjunctive aid in differential diagnosis between these two tumors.

Myoepithelial cell markers in salivary gland neoplasms

We compared the immunoexpression of 5 myoepithelial cell (MEC) markers (alpha-smooth-muscle actin, calponin, h-caldesmon, vimentin, and S-100-protein) using 16 pleomorphic adenomas (PA), 15 adenoid cystic carcinomas (ACC), and 3 epithelial-myoepithelial carcinomas (EMC) of salivary glands. The alpha-smooth-muscle actin was useful for identification of MECs, especially in cribriform and tubular ACC, followed by EMC. Calponin was similar to alpha-smooth-muscle actin, except for polygonal and plasmacytoid cells of PA and for solid ACC, which showed alpha-smooth-muscle actin negative and calponin positive. H-caldesmon was negative. Vimentin immunostained all MEC types, and was negative in luminal cells. S-100 protein was expressed both in the nuclei and cytoplasm of MECs and luminal cells, especially in PA. The best way to identify MEC is using alpha-smooth-muscle actin or calponin, plus vimentin, since in tumors MECs are hardly ever fully differentiated.

[Differential diagnosis of basaloid salivary gland tumors]

The diagnosis of basaloid tumors of the salivary glands can be challenging. In most cases, conventional histologic examination, if carried out meticulously, will be sufficient. Yet, immunohistochemistry will be of help for the definition of purely myoepithelial tumors, basaloid squamous cell carcinomas, and canalicular adenomas. The differential diagnosis of canalicular adenoma, basal cell adenoma and basal cell adenocarcinoma, adenoid cystic carcinoma, polymorphous low-grade adenocarcinoma, myoepithelial tumors, epithelial-myoepithelial carcinoma, and basaloid squamous cell carcinoma is discussed.

[Salivary gland tumors--tumor typing and grading]

In addition to staging, histological typing and grading provide important information for prognosis and adequate treatment of salivary gland cancers. Current classification and grading systems for mucoepidermoid carcinoma, adenoid cystic carcinoma, and malignant mixed tumor (carcinoma ex pleomorphic adenoma) are discussed.

Adenoid Cystic/Basal Cell Carcinoma of the Prostate

Adenoid cystic/basal cell carcinoma (ACBCC) of the prostate has been considered to have indolent biologic potential. However, outcome data are scant, with only one documented metastasis and death. We describe clinicopathologic features of ACBCC in 19 patients and document outcome in 15. Patients ranged in age from 43 to 83 years. All but one presented with urinary obstruction. ACBCC was diagnosed by transurethral resection in 15 cases, by needle biopsy in 3 cases, and unexpected in 1 case. Four patients had concurrent acinar adenocarcinoma. Histologically, cribriform or adenoid cystic patterns predominated in 12 cases and basal cell carcinoma pattern in 7. Five cases had prominent perineural invasion. ACBCC was immunoreactive for p63 and cytokeratins 7 and 34 beta E12 but not cytokeratin 20. After diagnosis, 5 patients underwent radical prostatectomy, 2 underwent pelvic exenteration, and the rest had no treatment. ACBCC showed extraprostatic extension in 5 cases and involved the bladder margin in 3. Metastases developed in 4 (21%) patients: liver (2), lung (2), bowel (1), and corpus cavernosum (1). In 15 cases with follow-up (0.3-11.8 years), two patients died of cancer (at 1.5 and 3 years after diagnosis), 3 remain alive with cancer, and 10 have no evidence of cancer. Thus, ACBCC of the prostate is a potentially aggressive neoplasm requiring ablative therapy.

Pleomorphic adenoma with extensive adenoid cystic carcinoma-like cribriform areas of parotid gland

We report an interesting case of pleomorphic adenoma (PA) with extensive adenoid cystic carcinoma (ACC)-like cribriform areas of parotid gland along with a discussion of the differential diagnosis. The patient was a 62-year-old-female who presented with a 5-month history of a slow-growing painless mass in the left preauricular region. Pathological examination of the excised mass revealed a well-encapsulated tumor consisting of typical PA areas and extensive ACC-like cribriform areas. The transition between both areas was frequently observed. There was no clinical or histological evidence of a longstanding PA, such as prominent hyalinization with dystrophic calcification. Immunohistochemically, the neoplastic myoepithelial cells of the PA areas showed frequent expression of vimentin and S-100 protein, along with occasional positivity for glial fibrillary acidic protein and alpha-smooth muscle actin. The immunoreactivity of the neoplastic myoepithelial/basal cells forming cribriform nests was essentially identical to that of the PA areas. The difference of immunoreactivity of the basal/myoepithelial cells between PA and ACC may have some discriminatory advantage. In addition, the low proliferative activity observed in the entire tumor suggested that the cribriform nests resembling ACC are also the component of PA.

Application of immunohistochemistry to the diagnosis of salivary gland tumors

A panel of antibodies composed of the cytokeratins (CKs), vimentin, and actin was applied to 114 minor salivary gland tumors to evaluate its diagnostic value. The results revealed that luminal cells of intercalated duct-like structures, such as those seen in pleomorphic adenoma, basal cell adenoma, adenoid cystic carcinoma, and epithelial-myoepithelial carcinoma, expressed CKs 7, 8, 14, and 19. The outer cells of these structures exhibited vimentin or vimentin plus muscle-specific actin, but rarely CK14, which is seen particularly in pleomorphic adenoma, in the tubular type of basal cell adenoma, and seldom in the tubular type of adenoid cystic carcinoma. Modified myoepithelial cells of pleomorphic adenoma and myoepithelioma exhibited a variable immunoprofile. CKs 7 and 8 were also observed in acinar cell adenocarcinoma and polymorphous low-grade adenocarcinoma with vimentin in the latter. CK13 was expressed only by canalicular adenoma and mucoepidermoid carcinoma cells. This study showed that the panel of antibodies employed is effective in distinguishing among salivary gland tumors.

Immunoreactivity of ductal cells with putative myoepithelial markers: A potential pitfall in breast carcinoma

The identification of an intact layer of myoepithelial cells (MECs) located between epithelial cells and the basal lamina is useful in differentiating benign breast lesions and carcinoma in situ from invasive breast carcinoma. In the present study we used three antibodies considered to be putative markers of MECs (S100 protein, muscle-specific actin [HHF-35], and smooth muscle actin [SMA]) in 100 formalin-fixed, paraffin-embedded histologic sections of breast in an attempt to compare their value in demonstrating MECs in benign breast tissue and breast carcinomas. We concluded that for identifying MECs in benign breast tissue, SMA appears to be the most reliable, followed closely by HHF-35, but S100 is very unreliable for this purpose. In breast carcinoma, all three stains showed variable cross-reactivity with myofibroblasts, being greatest with SMA. A significant number of tumor cells in ductal carcinoma, both intraductal and invasive, stain with these markers and this "cross-reactivity" is extremely high with HHF-35. Thus, immunohistochemistry should be interpreted cautiously in differentiating benign, in situ, and invasive breast neoplasms. The "cross-reactivity" also suggests the possibility of myoepithelial differentiation and/or high actin content of breast tumor cells.

The expanding clinical spectrum of desmoplastic small round-cell tumor: a report of two cases with molecular confirmation

Desmoplastic small round cell tumor (DSRCT) is an aggressive neoplasm characterized by a consistent histological appearance, a unique immunohistochemical profile, and a specific chromosomal translocation. DSRCT is also hallmarked by distinctive clinical features. Most tumors arise in adolescent or young adult males, present as bulky abdominal masses, and diffusely spread along the peritoneal surface. We report two cases of DSRCT that do not fit this typical profile. One case involved the abdominal cavity of a 76-year-old woman. The other case arose in the parotid of a 22-year-old man. Histologically, the tumors showed the characteristic features of DSRCT. Immunohistochemically, the tumors showed positivity for cytokeratin, desmin, and neuron-specific enolase. Genetically, the tumors expressed the EWS-WT1 chimeric transcript. These two cases expand the differential diagnosis for poorly differentiated small-cell tumors that involve elderly patients or arise in the parotid. Moreover, they challenge the popular notion that DSRCT is a "blastomatous" tumor derived exclusively from the primitive mesothelium.

Extracellular matrices expression in invasion area of adenoid cystic carcinoma of salivary glands

Adenoid cystic carcinoma (ACC) is a salivary malignant tumor with poor long-term prognosis, that is known to have predilection for invasion of the adjacent stroma and neural tissues. This carcinoma has shown a high incidence of recurrence and distal metastasis. Invasive carcinomas have been associated with the distributions of extracellular matrices (ECM). Cell proliferation as a marker of tumor growth has been related to poor prognosis in oral carcinomas. Immunohistochemical analysis of 15 cases of ACC was done using antibodies to laminin, type IV collagen, fibronectin, tenascin and anti-proliferating nuclear antigen (PCNA). Laminin and type IV collagen were totally or partially absent in the ACC invasive areas. Tenascin was expressed in the stroma and cytoplasm and was associated with tumor cell proliferation. It can be concluded that basement membrane represents a barrier that is lost during cell invasion and tenascin may be involved in the detachment of cancer cells, increasing the invasive potential of ACC.

[Basaloid squamous epithelial carcinoma of the mouth mucosa]

The basaloid-squamous carcinoma (BSC) that was first described in 1986 by Wain et al. for the head and neck region is a rare distinct variant of squamous cell carcinoma (SCC). The cardinal histopathologic feature is a biphasic cellular pattern of basaloid and squamous components. BSC has been confused with solid adenoid cystic carcinoma (ACC). Although the number of reported cases is small, BSC appears biologically virulent, with a propensity to aggressive local behavior, early regional and distant metastasis, and subsequent poor survival. We report the clinicopathological characteristics of 4 new cases and compare their immunohistochemical features with those of solid ACC and conventional SCC. Our results show that BSC, ACC and SCC react to CK 5/6. SCC is CK 10- and CK 13-positive, while BSC and ACC are negative for these markers. BSC and ACC react to CK 8, but in ACC only the luminal cells are CK 8 positive: therefore ACC has a glandular pattern. Our findings indicate that the immunohistochemical differences between BSC and ACC can facilitate their differential diagnosis. Because the biologic behavior of BSC differs from ACC and SCC, distinction among these tumor types is warranted.

Four cases of polymorphous low-grade adenocarcinoma

Since its histologic recognition by the World Health Organization in 1990, polymorphous low-grade adenocarcinoma (PLGA) is now regarded as the second most common salivary gland tumour after mucoepidermoid carcinoma. Distinguishing it from high-grade tumours such as adenoid cystic carcinoma or carcinoma arising within a pre-existing pleomorphic adenoma is important, as PLGA may usually be treated by local excision alone. Any evidence of incomplete marginal clearance, perineural and perivascular spread, and lymph-node involvement is treated with a course of radiotherapy. Follow-up should be for life, and as reported in this series, long-term survival rates are very good, one of our patients surviving for 11 years. The importance of reporting these cases is emphasized.

Identification of Metallothionein- and parathyroid hormone-related peptide (PTHrP)-positive cells in salivary gland tumours

Ductal basal cells and myoepithelial cells (MEC) of normal salivary gland share metallothionein (MT)-positivity, while PTHrP positivity is restricted to ductal basal cells. We studied 21 benign and 4 malignant tumours in which MEC are thought to play a role using immuno-histochemical methods for detecting the presence of MT and PTHrP positive cells. In benign tumours, a shared positivity for MT and PTHrP is found in the inner layer of tubulo-ductal and trabecular structures, in part of the cells in the myxoid and chondroid matrices of pleomorphic adenoma, and in the basal epithelial lining of Warthin's tumours. In myoepithelioma almost all tumour cells demonstrate MT reactivity and a restricted positivity for PTHrP. MT-positive cells in oncocytoma were demonstrated in the periphery of some oncocytic islets, while PTHrP positivity was restricted to a few oncocytic cells. In malignant tumours, positivity for MT is found in the periphery of epithelial clusters of mucoepidermoid carcinomas, while PTHrP-positive cells are seen in cyst-like structures and scattered cells in solid arrangements of squamous cells. Although the biologic significance of the presence of MT in neoplastic cells is not yet clearly understood, MT may be necessary for the growth and differentiation in actively growing cells. The variability of MT expression in salivary gland tumours could be a reflection of the morphological heterogeneity and correlate with the degree of differentiation and maturation of the tumour cells. The observations suggest that MT may be considered an oncodevelopmental product.

Elevated carcinoembryonic antigen levels correlating with disease recurrence in a patient with adenoid cystic carcinoma

BACKGROUND

Carcinoembryonic antigen (CEA) is an oncofetal glycoprotein involved in cell recognition and adhesion. Serum CEA has been extensively studied as a potential chemical marker for malignancy, most notably in patients with colon carcinoma. Serum CEA measurements have not been reported for patients with salivary gland carcinomas.

METHODS

Serum CEA was measured in a case study using enzyme immunoassay with monoclonal antibody specific for CEA. Tissue was examined with standard histologic and immunohistologic methods.

RESULTS

A patient was initially seen with adenoid cystic carcinoma (ACC) of the trachea and had a markedly elevated serum CEA level which declined after surgical resection. The serum CEA level became elevated again when the patient developed abdominal metastases and then declined after debulking of the tumor. Immunohistochemical study of the tumor was positive for CEA.

CONCLUSIONS

The measurement of serum CEA levels may play a role in the management of patients with ACC. Clinical investigation utilizing monoclonal antibodies against CEA, for imaging and for the delivery of chemotherapy and radiotherapy may be worthwhile.

Collagen IV and tenascin immunoreactivity as prognostic determinant in benign and malignant salivary gland tumours

The expression of collagen IV and tenascin was studied in a series of 219 salivary gland tumours with special emphasis on the prognostic significance of these extracellular matrix constituents. Continuous and uninterrupted staining of the basal membrane with collagen IV antibody was found in 62% (64/103) of the carcinomas and in 92% (107/116) of the benign tumours, the staining being weak and interrupted in 38% (39/103) and 8% (9/116) of cases, respectively. Weak immunoreactivity for collagen IV was significantly (p = 0.05) associated with recurrences of the malignant salivary gland tumours. Intense collagen IV staining of the basal membrane was more frequent (35.9%) in patients who were alive, as compared with that (19.4%) of the patients who died of salivary gland cancer (p = 0.03). Similarly, the intactness of the basal membrane was directly related to patient survival. In benign tumours, no such differences were found. In multivariate analysis, collagen IV immunoreactivity was related to the age of the patients (p = 0.007) and to tumour diameter > 4.0 cm (p = 0.005). Intense tenascin immunoreactivity was found in 45% (46/103) of the carcinomas and in 43% (50/116) of the benign tumours, 55% (57/103) and 57% (66/116) of the cases being entirely tenascin-negative, respectively. Tenascin immunoreactivity was not related to the clinical behaviour of malignant salivary gland tumours. In benign tumours, an intense staining for tenascin was a determinant of recurrent disease (p = 0.05). In multivariate analysis, tenascin immunoreactivity was intimately associated with erbB-2 positivity (p = 0.03) and weak staining of collagen IV (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Thomsen-Friedenreich (T) antigen as marker of myoepithelial and basal cells in the parotid gland, pleomorphic adenomas and adenoid cystic carcinomas. An immunohistological comparison between T and sialosyl-T antigens, alpha-smooth muscle actin and cytokeratin 14

Controversy centres on the role and identification of myoepithelial (MEC) and basal cells in salivary gland tumours, and recent studies suggest that both basal cells and myoepithelial cells participate in the formation of salivary gland tumours. We have correlated the expression of different well-known markers of normal MEC/basal cells (i.e. alpha-smooth muscle actin and cytokeratin 14) with T (Thomsen-Friedenreich) antigen and its sialylated derivative: sialosyl-T antigen,) in 17 normal parotid glands and in two tumour types with MEC participation (i.e pleomorphic adenomas (PA) and adenoid cystic carcinomas (ACC)) using immunohistology with well-defined monoclonal antibodies (MAbs). Paraffin-embedded/fresh frozen tissue sections were studied from 33/17 patients with PA and 15/7 patients with ACC. In normal parotid tissue coexpression of alpha-smooth muscle actin, cytokeratin 14, T and sialosyl-T antigens was found in all MEC and in some of the basal cells lining striated ducts. The remaining basal cells exclusively expressed cytokeratin 14, T and sialosyl-T antigens. In the tumours, cells believed to be modified myoepithelial cells showed two different staining patterns: 1) Coexpression of alpha-smooth muscle actin, cytokeratin 14, T and sialosyl-T antigens, and 2) Coexpression of cytokeratin 14, T and sialosyl-T antigens, but no alpha-smooth muscle actin. The epithelial ductular structures in the tumours showed aberrant expression of cytokeratin 14, T and sialosyl-T antigens, and cytokeratin 14 was the only marker of cells in solid undifferentiated areas of adenoid cystic carcinomas. Our study supports the view, that modified "myoepithelial" cells in the tumours consist of a mixture of basal cells and myoepithelial cells. None of the investigated structures was in itself an ideal marker in the identification of MEC/basal cells. The cells can be identified by a combination of markers (i.e. cytokeratin 14, alpha-smooth-muscle actin, T and sialosyl-T antigens).

Nucleolar organizer regions in adenoid cystic carcinoma of the salivary glands

In this study of proliferative activity of adenoid cystic carcinomas (ACCs) with different histological patterns, the argyrophilic staining method of nucleolar organizer regions (AgNORs) was applied to paraffin sections from 25 tumors. Sixteen of the neoplasms showed a mixture of different histological patterns in the same section. The AgNOR numbers in the different histological pattern areas in the same tissue sections of all 16 tumors were lowest in the cribriform, intermediate in the trabecular, and highest in the solid pattern areas. The mean AgNOR number was highest in the solid pattern (3.33 +/- 0.52), and lowest in the cribriform pattern (2.12 +/- 0.43). The results show the order of proliferative activity in the different histological pattern areas of ACC, and explain the previous clinical finding that the prognosis of ACC is poorest in solid pattern ACCs. AgNOR staining appears to be a useful technique for evaluation of the proliferative activity of each histological pattern area of ACC, especially when there are different histological pattern areas in the same tissue section.

Immunohistochemical analysis of salivary gland canalicular adenoma

Canalicular adenoma is a newly recognized salivary gland adenoma that may be confused with malignant salivary gland tumors. To better characterize this neoplasm, six examples were investigated with a panel of immunohistochemistry antibodies including anti-keratin (AE1/AE3), anti-epithelial membrane antigen, anti-carcinoembryonic antigen, anti-vimentin, anti-S-100, anti-muscle specific actin, and anti-glial fibrillary acid protein. All canalicular adenomas stained in a similar fashion showing positive staining with anti-keratin, anti-vimentin, and anti-S-100 (6 of 6 cases each). Rare focal staining with anti-epithelial membrane antigen and anti-glial fibrillary acid protein was noted (1 of 6 cases each). This immunohistochemistry staining pattern was compared with those of ameloblastoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma. Immunohistochemistry may be useful in the distinction of canalicular adenoma from other salivary gland tumors.

Pathology of the salivary glands: the contribution of electron microscopy

Electron microscopy has a limited role in the diagnosis of primary salivary gland tumors, although it can be helpful in metastatic lesions of possible salivary gland origin. The diversity of subtypes in salivary gland tumors, as well as the range of histomorphology within any one subtype, is unparalleled in any other human tumor. This and their relative infrequency causes diagnostic problems for pathologists. Ultrastructural techniques have been of major importance in determining the inter-relationship of these tumors for classification purposes, revealing the subtle variations in common cellular differentiation pathways, determining the organization of tumor cells, and displaying the importance of extracellular matrix materials in establishing diagnostic criteria for each of the many subtypes. Electron microscopy has also been valuable in non-neoplastic salivary gland disease and has an increasing role in experimental studies involving tissue from human and animal salivary parenchyma.

Histological changes during progression of adenoid cystic carcinoma

Eight cases of adenoid cystic carcinoma were reviewed to determine whether and how the histological features of the tumour vary with the progress of the disease. The tumours were classified by their histological patterns as tubular, cribriform, trabecular or solid. The relative amount of each pattern seen in routine light microscopic sections was calculated histomorphometrically and compared in the primary tumour and recurrent and/or metastatic lesions in the same case. In the early stage, the tubular pattern predominated. Later, the highest percentage shifted to the cribriform, then to the trabecular and finally, in the late stage, to the solid pattern. There was no reverse direction of histological transformation from the solid to the tubular pattern. These results may help to explain previous reports that the tubular pattern usually represents a favourable prognosis, the solid pattern a poor prognosis and the cribriform pattern an intermediate prognosis.

Nucleolar organizer regions in malignant salivary gland tumors

Proliferative activity of carcinomas arising from salivary glands was analyzed by enumeration of argyrophilic nucleolar organizer regions (AgNORs). The mean numbers of AgNORs in the various tumors were as follows: mucoepidermoid carcinoma, 2.20; acinic cell carcinoma, 2.51; adenoid cystic carcinoma (ACC), 2.57; carcinoma in pleomorphic adenoma, 1.00 (benign component) and 3.99 (cancer-bearing area); salivary duct carcinoma, 4.49; polymorphous low-grade adenocarcinoma, 3.37; sebaceous carcinoma, 2.57; oncocytic carcinoma, 4.63; adenocarcinoma, 4.53. Cells of most tumors showed heterogeneous activity within the same tumor. In mucoepidermoid carcinoma, the mucous cells had suppressed activity in comparison with the epidermoid cells and intermediate cells. In ACC, the activity of the tumor cells increased according to growth pattern in the order tubular, glandular and solid. In carcinoma in pleomorphic adenoma, vigorous proliferative activity was observed in the malignant component, whereas less active cells were seen in the myxoid or chondroid matrix. AgNOR staining was useful for distinguishing benign from malignant regions in carcinoma in pleomorphic adenoma. Our results suggest that mucoepidermoid carcinoma, acinic cell carcinoma and ACC, except for that with a solid growth pattern, may be considered as low-grade malignancies, whereas solid-type ACC, the cancer component in carcinoma in pleomorphic adenoma and some of the other carcinomas have high-grade malignant behavior.

Basement membrane proteins in salivary gland tumours. Distribution of type IV collagen and laminin

Immunohistochemical localization of type IV collagen and laminin in normal salivary glands and in salivary gland tumours of various types was studied using rabbit antisera. In normal salivary glands, type IV collagen and laminin were co-localized in basement membranes surrounding acini, ducts, fat cells and peripheral nerves. In salivary gland tumours, three main patterns of co-expression of these basement membrane proteins were distinguished. Linear basement membrane-like staining was detected in duct-cell-derived benign salivary gland tumours and in acinic cell carcinomas. In invasive lesions, however, these basement membrane proteins were distributed in an irregular, interrupted manner, and in many cases they were completely absent. Both benign and malignant salivary gland tumours which have a prominent myoepithelial cell component display a particular deposition of basement membrane molecules adjacent to the modified myoepithelial cells, and at the margins of extracellular matrix deposits within these tumours.

Trabecular and solid-cribriform types of basal cell adenoma. A morphologic study of two cases of an unusual variant of monomorphic adenoma

Monomorphic adenomas are a morphologically complex group of salivary gland tumors. Two unusual examples, one a trabecular and the other a solid form of basal cell adenoma, reveal the development of a cribriform growth pattern focally in the former example and diffusely in the latter. They illustrate the potential for cellular differentiation within this subgroup, organization of synthetic products by the tumor cells, and the histologic criteria useful for the distinction of basal cell adenoma from adenoid cystic carcinoma.

Basaloid-squamous carcinoma of the upper aerodigestive tract and so-called adenoid cystic carcinoma of the oesophagus: the same tumour type?

Basaloid-squamous carcinoma of the larynx, pharynx and base of tongue and the so-called adenoid cystic carcinoma of the oesophagus are rare but distinctive tumours associated with a grave prognosis. They occur most commonly in elderly males and present at an advanced stage. Our study of four such laryngeal tumours and five such oesophageal tumours shows that they are histologically and immunohistochemically identical, providing support for the idea that they are the same tumour type. They show a biphasic pattern in which basaloid tumour is intimately associated with a neoplastic squamous component which can be invasive or in situ. The basaloid component is in the form of invasive lobules with frequent comedo-necrosis and hyalinization. The constituent cells possess pale pleomorphic nuclei with frequent mitoses. Immunoreactivity for cytokeratin in the basaloid component is remarkable for its absence or weak and focal nature. Review of the literature shows that only a few cases of 'adenoid cystic carcinoma' of the oesophagus are bona fide examples of adenoid cystic carcinoma as it occurs in the salivary glands, while the others are identical to basaloid-squamous carcinoma of the upper aerodigestive tract. Their distinction is important because genuine adenoid cystic carcinoma is much less aggressive than basaloid-squamous carcinoma.

Polymorphous low-grade adenocarcinoma of minor salivary gland. A comparative histologic and immunohistochemical study

Sixteen polymorphous low-grade adenocarcinomas were reviewed and compared with 17 adenoid cystic carcinomas and with 21 other histologically similar minor salivary gland neoplasms. The polymorphous low-grade adenocarcinomas were for the most part distinctive in their microscopic appearance. Typically they exhibited infiltrative growth by small uniform cells in single-layered ducts. A syncytium of tumor cells was also characteristic, although solid and cribriform patterns were seen, making definitive diagnosis difficult with some tumors. Immunohistochemical staining for S-100 protein, glial fibrillary acidic protein, actin, vimentin, and keratins resulted in relatively distinctive antigenic profiles for the tumors studied. Of significance was strong S-100 protein and weak actin staining of polymorphous low-grade adenocarcinomas, moderate actin staining of adenoid cystic carcinomas, moderate glial fibrillary acidic protein staining of monomorphic adenomas and pleomorphic adenomas, and nonreactivity of monomorphic adenomas for vimentin. It is believed that the immunoprofiles could be useful in the microscopic diagnosis of salivary gland tumors. The identification of antigens found normally in myoepithelial and epithelial cells supports the concept that these tumors are derived from pluripotential reserve cells.