The cellular composition of adenoid cystic carcinoma. An immunohistochemical study

How predominant cell and stroma types harmonize to predict head and neck adenoid cystic carcinoma outcomes?

Adenoid cystic carcinoma (ACC) is an uncommon tumor that usually appears in the major salivary glands of the head and neck region, including the minor glands in the oral cavity, sinonasal tract, and other sites. ACC of the head and neck may have a low-grade histological appearance. This malignant tumor has unusual clinical characteristics such as occasional regional lymph node metastases and a prolonged yet continuously advancing clinical course. Additionally, it is an invasive tumor with perineural invasion, difficult-to-clear margins, metastasis, and localized recurrence. The cribriform and tubular proliferation of basaloid cells, which mostly display a myoepithelial cellular phenotype, are ACC's distinct histologic characteristics. The degree of genetic alterations and aneuploidy observed in tumor genomes are linked to the severity of histologic grade, which correlates with clinical prognosis. The three predominant cell types (PCTs) i.e., conventional ACC (C-ACC), myoepithelial-predominant ACC (M-ACC), and epithelial-predominant ACC (E-ACC)-and their respective applications will be reviewed. The function of extracellular matrix (ECM) components such as laminin, type IV collagen, fibronectin, and tenascin are also emphasized. An attempt has been made to explore the recent molecular diversity, regulatory pathways prevalent in PCT, ECM with its genetic changes, and translational utility with targeted therapies for ACC.

Salivary gland adenoid cystic carcinoma in the U.S population: Importance of grade, site of metastases, and adjuvant radiation for survival

BACKGROUND

Adenoid cystic carcinoma (AdCC) is a rare and relatively heterogenous salivary gland malignancy, for which there is debate regarding grading, and clinical prognostic factors, including the role of adjuvant radiotherapy.

METHODS

Surveillance, Epidemiology, and End Results (SEER) data were reviewed for AdCC cases from 2000 to 2018.

RESULTS

A total of 1978 patients with AdCC were identified. Most patients were between 50 and 59 years of age (21.4 %), female (59.9 %), and Caucasian (76.8 %). Most tumors were localized at presentation (44.3 %), and moderately differentiated (or grade II) (43.7 %). Overall and DSS 5-year survival rates were 70.7 % (95 % CI, 69.9-78.8), and 78.6 % (95 % CI, 77.6-79.6). The best overall 5-year survival rate was observed for those treated with surgery plus radiation, 76.8 % (95 % CI, 75.5-78.1). Multivariate analysis revealed male sex, age > 65 (H.R. 2.659 (95 % CI,2.291-3.098), p < .001), grade III/IV (H.R.5.172 (95 % CI, 3.418-7.824), p < .001), nodal metastasis, distant metastasis (H.R. 2.400 (95 % CI, 2.178-2.645), p < .001), chemotherapy only, and combination therapy as negative prognostic factors, and receiving surgery plus radiation therapy (H.R.0.586 (95 % CI, 0.505-0.679), p < .001) as a positive prognostic factor. When limited just to the lungs, had much better survival than those patients with distant metastases to other sites such as the bones and liver (p < .001).

CONCLUSION

This SEER study identifies grade, particularly III and IV, to be the strongest single predictor of worse survival. Patients did best when treated with surgery and postoperative radiotherapy. These results can inform future management of patients with this challenging cancer type.

Adenoid cystic carcinoma of the retromolar pad region: A case report

INTRODUCTION

Adenoid cystic carcinoma (ACC) is one of the most common salivary gland malignancies, mostly occurs in the major and minor salivary glands in the oral and maxillofacial region. The development of ACC in the retromolar pad is extremely rare, which limits establishing proper diagnosis and management.

PRESENTATION OF CASE

A patient described a 2-month history of finding a mass behind the lower left posterior teeth. Based on the physical examination and radiographic findings, we got an initial impression of a benign mucocele, the nature of which was to be investigated further. Pathological examination of the resected tissue resulted in a diagnosis of ACC. Follow-up visits showed no recurrence during the subsequent 54 months.

DISCUSSION

In cases with an uncertain diagnosis based on medical history, clinical features and imaging examinations, it is important to proceed carefully with the possibility of a tumor in mind.

CONCLUSION

ACC in the retromolar pad is rare and can be easily misdiagnosed. Clinical, radiographic, and pathological evidence confirm a definitive diagnosis. Long-term follow-up is important for the full analysis of ACC treatment.

Inverse agonists of retinoic acid receptor/retinoid X receptor signaling as lineage-specific antitumor agents against human adenoid cystic carcinoma

BACKGROUND

Adenoid cystic carcinoma (ACC) is a lethal malignancy of exocrine glands, characterized by the coexistence within tumor tissues of 2 distinct populations of cancer cells, phenotypically similar to the myoepithelial and ductal lineages of normal salivary epithelia. The developmental relationship linking these 2 cell types, and their differential vulnerability to antitumor treatments, remains unknown.

METHODS

Using single-cell RNA sequencing, we identified cell-surface markers (CD49f, KIT) that enabled the differential purification of myoepithelial-like (CD49fhigh/KITneg) and ductal-like (CD49flow/KIT+) cells from patient-derived xenografts (PDXs) of human ACCs. Using prospective xenotransplantation experiments, we compared the tumor-initiating capacity of the 2 cell types and tested whether one could differentiate into the other. Finally, we searched for signaling pathways with differential activation between the 2 cell types and tested their role as lineage-specific therapeutic targets.

RESULTS

Myoepithelial-like cells displayed higher tumorigenicity than ductal-like cells and acted as their progenitors. Myoepithelial-like and ductal-like cells displayed differential expression of genes encoding for suppressors and activators of retinoic acid signaling, respectively. Agonists of retinoic acid receptor (RAR) or retinoid X receptor (RXR) signaling (all-trans retinoic acid, bexarotene) promoted myoepithelial-to-ductal differentiation, whereas suppression of RAR/RXR signaling with a dominant-negative RAR construct abrogated it. Inverse agonists of RAR/RXR signaling (BMS493, AGN193109) displayed selective toxicity against ductal-like cells and in vivo antitumor activity against PDX models of human ACC.

CONCLUSIONS

In human ACCs, myoepithelial-like cells act as progenitors of ductal-like cells, and myoepithelial-to-ductal differentiation is promoted by RAR/RXR signaling. Suppression of RAR/RXR signaling is lethal to ductal-like cells and represents a new therapeutic approach against human ACCs.

Translocations and Gene Fusions in Sinonasal Malignancies

PURPOSE OF REVIEW

During the past few years there has been an expansion in our understanding of gene fusions and translocations involved in cancer of the sinonasal tract. Here we review the downstream biologic effects, clinical characteristics, and pathologic features of these tumors. The molecular consequences and neo-antigens resulting from these chromosomal aberrations are considered and targets for current and future clinical trials discussed.

RECENT FINDINGS

Several new, clinically relevant, chromosomal aberrations have been discovered and evaluated to varying degrees in sinonasal tumors including DEK::AFF2, BRD4::NUT, ADCK4::NUMBL, and ETV6::NTRK3. Sinonasal malignancies demonstrate a diverse genetic landscape and varying clinical courses. Recent studies illustrate that gene fusions and translocations may play a role in carcinogenesis in certain sinonasal tumor subtypes and may be used to develop new biomarker-driven and patient-centered treatments.

Challenges in management of Bartholin gland leiomyoma: A case report

Leiomyomas are uncommon vulvar neoplasms often misdiagnosed as other Bartholin gland pathology. This case report describes a case of accelerating growth of a vulvar mass, initially diagnosed as Bartholin cyst. Surgical excision led to a histopathologic diagnosis of vulvar leiomyoma. The postoperative recovery was complicated by secondary hematoma and dehiscence of the surgical site. There was no recurrence at 2 years follow-up.

Adenoid cystic carcinoma of the Bartholin's gland is easily misdiagnosed: A case report and literature review

RATIONALE

Adenoid cystic carcinoma (ACC) often occurs in the major and minor salivary glands and other sites containing secretory glands, while ACC of the Bartholin's gland (BG-ACC) in the vulva is rare and easily misdiagnosed.

PATIENT CONCERNS

A 58-year-old female was referred to our hospital for further valuation of a mass occurring on the left side of her vulva. In the other hospital, the beginning of the period, local ultrasound showed a vulva mass, which was suspected to be a Bartholin's gland cyst. Mixed neoplasms were considered in some biopsies. When transferred to our hospital, virtuous tumors were considered by ultrasound and magnetic resonance imaging. Pathology initially considered benign hyperplastic active tumor or borderline tumor.

DIAGNOSES

Histological, immunochemical, and molecular tests confirmed a diagnosis of BG-ACC, negative surgical margin, without lymphatic metastasis.

INTERVENTIONS

Extended excision of the mass at left labia majora plus left inguinal lymph node dissection was performed.

OUTCOMES

The patient received surgery therapy, no recurrence was observed during a 18-month follow-up period.

LESSONS

Due to its lack of specific characteristics in clinical, ultrasound and imaging, it is easy to be misdiagnosed, Due to its rarity and nonspecific clinical, radiologic and ultrasonographic manifestations, BG-ACC can be easily misdiagnosed. And its pathomorphological features overlap with other benign and malignant tumors occurring at vulva, BG-ACC can be easily misdiagnosed, and diagnosis by puncture biopsy is extremely difficult. Use of paraffin sections to identify tumor growth characteristics, combined with immunohistochemical findings, is the key to the diagnosis of ACC. In rare sites, MYB gene split are helpful in making a definite diagnosis.

PSMA PET Imaging and Therapy in Adenoid Cystic Carcinoma and Other Salivary Gland Cancers: A Systematic Review

Simple Summary

Adenoid cystic carcinoma (ACC) and other salivary gland cancers (SGC) are rare conditions with limited treatment options when they recur or spread to other parts of the body. There is increasing interest in the interaction of radioactive labeled proteins 68Gallium- Prostate Specific Membrane Antigen (68Ga-PSMA) with their corresponding receptors on tumor cells (PSMA receptor) which can be detected on scans. This innovation has created diagnostic and therapeutic progress in management of metastatic prostate cancer. These interactions are also found in SGCs though studies are currently limited. Our systematic review aims to collate available published scientific information on this technology to better inform its potential use, pitfalls and its future directions as a diagnostic and therapeutic option in SGCs. We concluded that the 68Ga-PSMA scans can be useful in detecting ACC and SGC not detected on standard radioimaging and that small studies have shown the therapeutic potential of this innovation in advanced or metastatic ACC and SGC.

Abstract

Adenoid cystic carcinoma (ACC) and other salivary gland cancers (SGCs) are rare tumors where application of prostate specific membrane antigen (PSMA) positron emission tomography (PET) and PSMA radioligand therapy have yet to be studied extensively. This review explores the role of PSMA PET imaging and therapy as a theranostic tool for ACC and other SGCs based on current literature. A comprehensive literature search on PubMed and Embase was performed. All relevant studies containing information on PSMA PET imaging in ACC and SGC were included. Ten studies (one prospective, three retrospective, five case reports and one review paper) were included. For ACC, the mean maximum standardized uptake value (SUVmax) for local recurrence and distant metastases ranged from 2.41 to 13.8 and 2.04 to 14.9, respectively. In SGC, the meanSUVmax ranged from 1.2–12.50. Most studies observed PSMA expression positivity on immunohistochemistry (IHC) when there was PSMA PET uptake. PSMA PET was able to detect lesions not detected on standard imaging. Despite the small number of studies and wide intra-patient and inter-tumor variation of PSMA uptake in ACC and SGC, 68Gallium (68Ga)-PSMA PET has promising prospects as a diagnostic and radioligand therapeutic option. Further studies to answer the various theranostics considerations are required to guide its use in the real-world setting.

Radiation Therapy for Adenoid Cystic Carcinoma of the Head and Neck

Simple Summary

Adenoid cystic carcinoma is a rare histology arising in the head and neck region that has a high propensity for perineural invasion. While surgical resection is the preferred primary treatment modality, adjuvant radiotherapy is often indicated to improve local control. For unresectable disease, definitive radiotherapy can be utilized. Given the predilection for perineural tumor spread, target volumes often must encompass relevant nerve pathways back to the base of skull. Treatment strategies for ACC must therefore balance the disease burden and risk of failure against the morbidity of treatment.

Abstract

Adenoid cystic carcinoma of the head and neck is an uncommon malignancy that can arise in the major or minor salivary glands. Perineural invasion (PNI) is an extremely frequent finding in cases of adenoid cystic carcinoma (ACC) that can be associated with significant patient morbidity and poor prognosis. By contrast, ACC rarely demonstrates lymphovascular space invasion thereby making PNI the major avenue for metastasis and a driver of treatment rationale and design. Radiotherapy is often utilized post-operatively to improve locoregional control or as a primary therapy in unresectable disease. Here we aim to review the role of radiotherapy in the management of this malignancy with a focus on target delineation and treatment regimens in the definitive, recurrent, and metastatic settings.

Homeobox transcription factor engrailed homeobox 1 is a possible diagnostic marker for adenoid cystic carcinoma and polymorphous adenocarcinoma

Diagnostic utility of a homeobox transcription factor, engrailed homeobox 1 (En1) in the histopathology of salivary gland neoplasms was studied. The expression of En1 was immunohistochemically examined in 51 cases of adenoid cystic carcinoma (AdCC) and 143 cases of other salivary gland neoplasms. In all 51 AdCCs, En1 was expressed in 30-100% of tumor cells. In eight of nine polymorphous adenocarcinomas (PACs), En1 was expressed in 40-100% of tumor cells. Less than 5% of tumor cells expressed En1 in three of 12 epithelial-myoepithelial carcinomas, one of 17 basal cell adenomas (BCAs), and one of 34 pleomorphic adenomas (PAs). Among 55 other carcinoma cases, 1-30% of tumor cells expressed En1 in three salivary duct carcinomas (SDCs) ex PA. None of the myoepitheliomas and Warthin tumors expressed En1. When the cut-off value of the percentage of En1-expressing cells was set to 25%, all 51 AdCCs, eight of nine PACs and one SDC ex PA were En1-positive and the others were En1-negative. En1 is expressed consistently in AdCCs, frequently in PACs, but rarely in other salivary gland neoplasms. En1 is a possible diagnostic marker for AdCC and PAC in the histopathology of salivary gland neoplasms.

Molecular and Cellular Modelling of Salivary Gland Tumors Open New Landscapes in Diagnosis and Treatment

Salivary gland tumors are neoplasms affecting the major and minor salivary glands of the oral cavity. Their complex pathological appearance and overlapping morphological features between subtypes, pose major challenges in the identification, classification, and staging of the tumor. Recently developed techniques of three-dimensional culture and organotypic modelling provide useful platforms for the clinical and biological characterization of these malignancies. Additionally, new advances in genetic and molecular screenings allow precise diagnosis and monitoring of tumor progression. Finally, novel therapeutic tools with increased efficiency and accuracy are emerging. In this review, we summarize the most common salivary gland neoplasms and provide an overview of the state-of-the-art tools to model, diagnose, and treat salivary gland tumors.

A middle-aged man with adenoid cystic lung carcinoma: not every dyspnoea is the novel coronavirus, even during a pandemic

Background:

A middle-aged gentleman presenting with dyspnoea was presumptively assumed to be a novel coronavirus suspect.

Findings:

Nasopharyngeal and oropharyngeal swabs were reported negative, and clinico-radiological workup revealed a case of adenoid cystic carcinoma (ACC) of the lung with metastases to the contralateral lung and the lumbar vertebrae.

Conclusion:

ACC is a rare malignancy of exocrine glands. Most commonly found in the minor salivary glands, they may rarely occur in other sites. Primary ACC of the lung is a rare histologic subtype that is encountered infrequently in clinical practice for which standard guidelines do not exist.

Activation of PLAG1 and HMGA2 by gene fusions involving the transcriptional regulator gene NFIB

The pleomorphic adenoma (PA), which is the most common salivary gland neoplasm, is a benign tumor characterized by recurrent chromosome rearrangements involving 8q12 and 12q14-15. We have previously shown that the PLAG1 and HMGA2 oncogenes are the targets of these rearrangements. Here, we have identified previously unrecognized subsets of PAs with ins(9;8)/t(8;9) (n = 5) and ins(9;12)/t(9;12) (n = 8) and breakpoints located in the vicinity of the PLAG1 and HMGA2 loci. RNA-sequencing and reverse transcriptase (RT)-PCR analyses of a case with an ins(9;8) revealed a novel NFIB-PLAG1 fusion in which NFIB exon 4 is linked to PLAG1 exon 3. In contrast to the developmentally regulated PLAG1 gene, NFIB was highly expressed in normal salivary gland, indicating that PLAG1 in this case, as in other variant fusions, is activated by promoter swapping. RT-PCR analysis of three PAs with t(9;12) revealed two tumors with chimeric transcripts consisting of HMGA2 exon 4 linked to NFIB exons 9 or 3 and one case with a fusion linking HMGA2 exon 3 to NFIB exon 9. The NFIB fusion events resulted in potent activation of PLAG1 and HMGA2. Analysis of the chromatin landscape surrounding NFIB revealed several super-enhancers in the 5'- and 3'-parts of the NFIB locus and its flanking sequences. These findings indicate that PLAG1 and HMGA2, similar to MYB in adenoid cystic carcinoma, may be activated by enhancer-hijacking events, in which super-enhancers in NFIB are translocated upstream of PLAG1 or downstream of HMGA2. Our results further emphasize the role of NFIB as a fusion partner to multiple oncogenes in histopathologically different types of salivary gland tumors.

Adenoid cystic carcinoma of the parotid metastasising to the dura fifteen years post primary resection: A case report

Adenoid cystic carcinoma (ACC), regardless of the primary site, is typically characterized by a long clinical course associated with a high rate of distant metastases. Intracranial metastasis of ACC is a very rare entity with only few reported cases in the literature. In this study, we report an unusual case of extra-axial intracranial metastasis of ACC in the dura. The primary parotid gland tumour was resected 15 y back. No recurrence had been detected before the occurrence of extra-axial metastasis. After surgical decompression, palliative radiotherapy was administered. To our knowledge, this is the longest interval for the development of metastases following excision of a parotid adenoid cystic carcinoma. This case can raise awareness across specialties that patients with adenoid cystic carcinoma are still at risk of developing metastases even following specialist discharge.

Disparities in Postoperative Therapy for Salivary Gland Adenoid Cystic Carcinomas

OBJECTIVES

The patterns of care for salivary gland adenoid cystic carcinomas (ACC) are unknown. We sought to assess predictors of receiving postoperative radiation and/or chemotherapy for patients with nonmetastatic, definitively resected ACC, as well as report unexpected nodal disease.

METHODS

The National Cancer Data Base was queried for definitively resected nonmetastatic ACC from 2004 to 2014. Logistic regression, Kaplan-Meier, and Cox proportional-hazard models were utilized. Propensity-score matched analysis was employed to reduce confounding variables.

RESULTS

A total of 3,136 patients met entry criteria: 2,252 (71.8%) received postoperative radiation, with 223 (7.4%) also receiving concurrent chemotherapy. Median follow-up was 4.87 years. In clinically lymph node negative (cN0) patients, 7.4% had pathologically positive lymph nodes (pN) + after elective neck dissection. Patients who lived closer to their treatment facility and had positive margins were more likely to receive postoperative radiation. Black patients and uninsured patients were less likely to receive radiation. Older age, male sex, advancing stage, and positive surgical margins were associated with worse overall survival (OS). With limited follow-up, receipt of radiation or chemotherapy was not associated with OS.

CONCLUSION

Postoperative radiation was frequently given for resected ACC, with a minority receiving chemotherapy. Black patients and uninsured patients were less likely to receive radiation. Postoperative radiation and/or chemotherapy had no association with OS but were given in greater frequency in more advanced disease, and our series is limited by short follow-up. The disparity findings for this rare disease need to be addressed in future studies.

LEVEL OF EVIDENCE

2c Laryngoscope, 129:377-386, 2019.

Palatal Polymorphous Adenocarcinoma with High-Grade Transformation: A Case Report and Literature Review

Polymorphous adenocarcinoma (PAC) is the second most common intraoral malignant neoplasm of the minor salivary glands. However, it is very rare for PAC to show high-grade transformation (HGT) and to our knowledge, the English literature only seven reported cases. HGT tends to be observed when PAC recurs, and it is extremely rare to be seen at initial presentation. Here we report a 43-year-old Japanese male patient with PAC of the right palate showing HGT at initial presentation. Histopathologically, the tumor was characterized by a prominent solid and papillary-cystic growth pattern, with nuclear atypia and necrosis in area of HGT. The immunohistochemical staining pattern was consistent with PAC, as the tumor cells showed diffuse positivity for cytokeratin, vimentin and S-100, and focal positivity for bcl-2, ɑ-SMA and EMA. The tumor cells in HGT areas were markedly positive for AR and Ki-67 (about 40%/HPF), and also focally positive for cyclin D1 and p53, whereas HER2/neu, ER, PgR, p63, D2-40, GCDFP-15, and mitochondria were negative. Here we present a very rare case of palatal PAC with HGT at initial presentation.

Adenoid Cystic Carcinoma of the Oral Cavity: Radiology-Pathology Correlation

Adenoid cystic carcinoma in the oral cavity is an uncommon salivary gland malignancy that has a propensity for perineural spread. A high-grade variant is evidenced by an abundance of pleomorphic cells, loss of the classic biphasic epithelial-myoepithelial growth pattern, and comedonecrosis, as well as elevated Ki-67. CT and MRI can both be useful for demonstrating the extent of invasion in oral cavity-associated adenoid cystic carcinoma, which can attain the inferior alveolar nerve for perineural spread by direct invasion through the mandible. Reflecting the aggressive nature of this high-grade malignancy, ¹⁸FDG-PET can demonstrate hypermetabolism and can be useful for staging. These features are exemplified in this sine qua non radiology-pathology correlation article.

Axillary lymph node metastases in adenoid cystic carcinoma of the breast. A rare finding

Adenoid cystic carcinoma (ACC) of the breast is a rare malignant salivary-type neoplasm that has a good prognosis and represents less than 1% of all breast cancers. It is a triple negative carcinoma that presents as a painful mass. The mean age at the time of diagnosis is 50-60 years old. The solid variant of this type of tumour with basaloid features and presence of nodal metastases is very rare and considered to have a more aggressive clinical course. We present a case with presence of axillary lymph node metastases that was successfully treated with no evidence of recurrence one year after the diagnosis and review the literature.

Adenoid cystic carcinoma: A review of recent advances, molecular targets, and clinical trials

Background

Adenoid cystic carcinoma (ACC) is a rare tumor of secretory glands. In this study, recent advances in molecular characterization and in therapeutics are reviewed.

Methods

A search of articles in PubMed and of abstracts from national meetings was performed regarding ACC.

Results

Recent genetic analyses found that recurrent chromosome 6:9 translocations in ACC generate an MYB:NFIB gene fusion resulting in overexpression of the MYB oncoprotein. Several other frequent mutations are recently published that may be relevant for drug development. Several trials of targeted drugs are reviewed. Some agents delay tumor progression, but tumor responses remain rare.

Conclusion

ACCs have a characteristic chromosomal translocation, but also frequently pick up additional mutations. Clinical research is limited by the rarity and slow growth of ACC. Several ongoing trials are testing agents that inhibit fibroblast growth factor receptor signaling or other signaling pathways. Novel treatments based on the recently sequenced tumor genome are under development. © 2015 The Authors Head & Neck Published by Wiley Periodicals, Inc. 38: 620–627, 2016

Adenoid cystic carcinoma of cervix: two cases report and review of the literature

Adenoid cystic carcinoma of the cervix is a rare and aggressive tumor with fatal outcome. In this paper we report two cases of primary adenoid cystic carcinoma and a review of literature. A 80 years old woman, admitted to our hospital with postmenopausal bleeding and hydrorrhea. Gynealogical examination showed a cervical stenotic with the presence of a tumor processus. Biopsy of cervical growth was done. 80-year-old woman presented with vaginal bleeding with pelvic pain. Physical examination revealed a friable mass in the cervix. Incisional biopsy was performed. In the both cases the diagnosis of adenoid cystic carcinoma of the cercix was confirmed. Adenoid cystic carcinoma of the cervix is clinically and radiologically similar to other tumors of the cervix but the diagnosis can only be made by histological examination.

Adenoid cystic carcinoma: An unusual presentation

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 regions. Peak incidence occurs between the 5^th and 6^th decades of life. The clinical and pathological findings typical of this tumor include slow growth, peri-neural invasion, multiple local recurrences and distant metastasis. Herein, we report a case of adenoid cystic carcinoma of oropharynx with unusual clinical presentation. The diagnosis of this case and importance of cytology in diagnosing such cases is discussed.

Moderately differentiated neuroendocrine carcinoma (atypical carcinoid) of the parotid gland: report of three cases with contemporary review of salivary neuroendocrine carcinomas

Primary neuroendocrine carcinomas (NECs) of the salivary glands are rare. Most reported NECs in that region are small cell carcinomas with few cases of large cell undifferentiated carcinoma and typical carcinoid tumors. Only two moderately differentiated NECs (atypical carcinoid tumors) have been previously reported. In the current series, the authors report three additional moderately differentiated NECs (atypical carcinoid tumors) of the parotid gland; two occurred in women and one in a man. All patients were initially treated with parotidectomy, with selective lymph node excision in one, and radiation therapy in another. Follow-up was available for two cases (18 and 79 months). One patient had two local recurrences, developing lymph node and liver metastases requiring further surgery and chemotherapy. Currently, she is alive with disease, on supportive care. The second patient is alive with no signs of recurrence. Patients' work-up excluded the possibility of metastatic NECs to the salivary glands in all cases. Histologically, the tumors demonstrated infiltrating nests, cords and trabeculae of round, oval to spindle shaped cells with moderate to focally abundant eosinophilic cytoplasm, small to prominent nucleoli and chromatin stippling. Scattered rosette-like structures were prominent in one tumor. The highest mitotic counts for the three tumors ranged from 5 to 8 mitotic figures/10 hpfs. Necrosis, focal but distinct, was noted in two tumors, vascular invasion in two tumors and perineural invasion in one tumor. Immunohistochemical staining was diagnostic of neuroendocrine carcinoma, showing uniform positive labeling with broad-spectrum cytokeratin (with a paranuclear punctuate pattern in one case), chromogranin and synaptophysin antibodies. CK20 was negative in two tumors and stained rare cells (<1%) in the third.

Analysis of MYB expression and MYB-NFIB gene fusions in adenoid cystic carcinoma and other salivary neoplasms

Recent studies have shown that the recurrent t(6;9)(q22-23;p23-24) translocation in adenoid cystic carcinoma results in a novel fusion of the MYB proto-oncogene with the transcription factor gene NFIB. To determine the frequency of this finding, we used RT-PCR assays of the MYB and MYB-NFIB fusion transcripts, and immunohistochemistry for the MYB protein, to study adenoid cystic carcinomas and other epithelial tumors of the salivary glands, and head and neck region. MYB-NFIB fusion transcript was detected in 25 of 29 (86%) frozen adenoid cystic carcinoma tumor samples, and in 14 of 32 (44%) formalin-fixed paraffin-embedded adenoid cystic carcinoma tumor specimens. In contrast, the MYB-NFIB fusion was not expressed in non-adenoid cystic carcinoma neoplasms of the head and neck, confirming the high specificity of the MYB-NFIB fusion. Adenoid cystic carcinomas from various anatomic sites, including salivary gland, sinonasal cavity, tracheobronchial tree, larynx, breast, and vulva were repeatedly fusion-positive, indicating that adenoid cystic carcinomas located in different anatomic sites not only have important morphologic features in common, but also probably evolve through activation of the same molecular pathways. Studies of the expression of MYB revealed that 89% of the tumors, including both fusion-positive and fusion-negative cases, overexpressed MYB RNA. Similarly, 82% of adenoid cystic carcinomas stained positive for MYB protein, compared with 14% of non-adenoid cystic carcinoma neoplasms, indicating that MYB immunostaining may be useful for the diagnosis of adenoid cystic carcinoma, but that neoplasms sometimes in the differential diagnosis are also labeled. The latter are, however, fusion-negative. In summary, our studies show that MYB activation through gene fusion or other mechanisms is a major oncogenic event in adenoid cystic carcinoma occurring at various anatomic sites. In addition to being a diagnostically useful biomarker for adenoid cystic carcinoma, MYB and its downstream effectors are also novel potential therapeutic targets.

Adenoid cystic carcinoma

Adenoid cystic carcinoma is a malignant tumor with a deceptively benign histologic appearance characterized by indolent, locally invasive growth with high propensity for local recurrence and distant metastasis. The tumor is composed of basaloid cells with small, angulated, and hyperchromatic nuclei and scant cytoplasm arranged into 3 prognostically significant patterns: cribriform, tubular, and solid. Some tumors undergo dedifferentiation into a high-grade form. Numerous studies have attempted to elucidate accurate histologic prognostic features but have often yielded conflicting results. Microarray analysis and gene expression profiling have provided new potential diagnostic and prognostic markers. However, tumor grade, stage, lymph node metastasis, invasion of major nerves, and margin status remain the most consistent predictors of prognosis. The combination of surgery and postoperative radiation therapy has improved locoregional control of the disease. Despite this achievement, late local recurrence and distant metastasis rates remain high and may occur decades after initial diagnosis.

Adenoid cystic carcinoma of the breast in the United States (1977 to 2006): a population-based cohort study

Introduction

Adenoid cystic carcinoma of the breast (breast-ACC) is a rare and special type of basal-like tumor for which scant population-based descriptive data exist. We sought to provide new population-based information on breast-ACC incidence, relative survival, and associated cancer risk in the United States.

Methods

Using data from the Surveillance, Epidemiology and End Results Program, we calculated age-adjusted incidence rates (IRs), IR ratios (IRRs), and relative survival for breast-ACC, and standardized incidence ratios (SIRs) for other cancers.

Results

Overall 338 women (IR = 0.92/1 million person-years) were diagnosed with breast-ACC during 1977 to 2006. Blacks had 39% lower IRs than Whites (IRR = 0.61, 95% confidence interval = 0.37 to 0.96), and IRs remained constant over the 30-year period. Ninety-five percent of cases presented with localized stage (n = 320; IR = 0.87), and the highest IRs were observed for estrogen receptor (ER)-negative/progesterone receptor (PR)-negative tumors (IR = 0.56). Like other typically ER-negative tumors, age-specific IRs increased until midlife and then plateaued. Five-year, 10-year, and 15-year relative survival was 98.1%, 94.9%, and 91.4%, respectively. The risk of female breast cancer was not increased following (SIR = 0.89, 95% confidence interval = 0.43 to 1.64) or preceding (SIR = 0.71, 95% confidence interval = 0.28 to 1.46) breast-ACC. Similarly, no association was observed for breast-ACC and risk of all other cancers combined, solid tumors, or lymphohematopoietic malignancies.

Conclusions

Breast-ACC among women is characterized by ER-negative/PR-negative expression, rare regional lymph node involvement, a favorable prognosis with excellent survival, and absence of associated cancers. These findings reinforce the importance of tailored treatments for breast-ACC and lend credence to the apparent heterogeneity of basal-like breast cancers.

Adenoid Cystic Carcinoma of the Bartholin Gland: An Overview

Vulvar carcinoma is the fourth most frequently encountered malignancy of the female reproductive tract. Among vulvar neoplasms, 0.1% to 5% are of Bartholin gland origin. Primary adenoid cystic carcinoma of the Bartholin gland is very rare. To date, only about 60 cases have been reported in the world literature. Microscopic examination reveals a neoplasm of cribriform pattern composed of nests and columns of cells of bland appearance arranged concentrically around glandlike spaces filled with eosinophilic periodic acid-Schiff–positive diastase-resistant material. Immunohistochemically, the tumor cells express low-molecular-weight keratins, carcinoembryonic antigen, lysozyme, α1-antichymotrypsin, S100, and type IV collagen. Adenoid cystic carcinoma of the Bartholin gland is a slow-growing but locally very aggressive neoplasm with high capacity for recurrence. Perineural and lymphatic invasion is characteristic of this tumor and may explain its propensity for causing pain and recurrence. The treatment may range from simple local excision to radical vulvectomy, with or without partial to complete regional lymphadenectomy.

Application of α-smooth muscle actin and c-kit in the differential diagnosis of adenoid cystic carcinoma from polymorphous low-grade adenocarcinoma

The expression of vimentin, alpha-smooth muscle actin (alpha-SMA) and c-kit in adenoid cystic carcinomas (AdCCs) and polymorphous low-grade adenocarcinomas (PLGAs) was investigated immunohistochemically to evaluate the application of these markers to distinguish AdCCs from PLGAs when the histological features are equivocal. Tissue specimens of AdCCs and of PLGAs, formalin-fixed and paraffin-embedded were retrospectively studied using vimentin, alpha-SMA and c-kit. Positive staining for alpha-SMA was identified in all AdCCs and 25% of PLGAs. The immunoreactivity of c-kit in all positive cases of AdCCs (83%) and PLGAs (41%) was more than 50% and less than 50% of tumor cells respectively. The expression pattern for both alpha-SMA and c-kit, in tubular structures of AdCCs was different of that seen in the same structures in PLGAs. The results of this study support the potential application of alpha-SMA and c-kit as an adjunctive aid in the differential diagnosis of AdCCs from PLGAs.

The sclerosing variant of adenoid cystic carcinoma. A previously unrecognized neoplasm of major salivary glands

We report 2 cases of a previously unrecognized sclerosing variant of adenoid cystic carcinoma (ACC) of major salivary glands. One of the tumors arose in the parotid and the other in the submaxillary gland of young adult patients. The tumors were composed predominantly of varying-sized large sclerotic and hypocellular nodules containing myoepithelial cells and pseudovascular spaces, most likely the result of artifactual retraction. In moderately cellular nodules, there were numerous small globules or spherules surrounded by myoepithelial cells similar to those of collagenous or mucinous spherulosis. Focal cribriform areas and ductal structures lined by epithelial cells were also identified. Both tumors showed perineural invasion. Electron microscopy revealed that both large nodules and small globules or spherules were composed of excessive amounts of basement membrane and thick-banded collagen fibers. The myoepithelial cells showed immunoreactivity for smooth muscle actin (SMA), S100 protein, and vimentin. Collagen IV showed variable reactivity in both the large nodules and small spherules. More cases of the sclerosing variant of ACC and long-term follow-up of the patients are needed to determine the biologic behavior of this unusual but distinctive variant of ACC.

KIT is highly expressed in adenoid cystic carcinoma of the breast, a basal-like carcinoma associated with a favorable outcome

Recent biological studies have classified breast carcinomas into HER2-overexpressing, estrogen receptor-positive/luminal, basal- and normal-like groups. According to this new biological classification, the objectives of our study were to assess the clinical, morphologic and immunophenotypic characteristics of adenoid cystic carcinoma of the breast in order to classify this subtype of breast carcinoma. A total of 18 cases of adenoid cystic carcinoma were identified from the Institut Curie files. Clinical information was available for 16 patients with a median follow-up of 6.5 years. Morphologically, all tumors were graded according to the system defined by Kleer and Oberman (histologic and nuclear grade). Immunophenotype was assessed with anti-ER, PR, HER-2, KIT, basal (CK5/6) and luminal cytokeratins (CK8/18) and p63 antibodies. One out of 18 tumors was nuclear grade 1 (16%), nine were nuclear grade 2 (50%) and eight were nuclear grade 3 (44%). All cases were estrogen receptor, progesterone receptor and HER-2 negative. Epithelial cells were strongly positive around glandular lumina with one or both cytokeratins, identifying the coexistence of CK5/6+ cells, CK5/6 and CK8/18+ cells, CK8/18+ cells and p63+ cells. All cases (100%) were also KIT positive. In all, 15 patients were treated by surgery. Nine of them received adjuvant radiotherapy. Follow-up was available for 16 patients. In all, 14 patients were alive. Two of them, initially treated by surgery only, presented a local recurrence. Two patients died (one of them treated by radiation therapy only died from her disease). Our study shows that adenoid cystic carcinoma of the breast is a special, estrogen receptor, progesterone receptor, HER-2 negative and highly KIT-positive, basal-like breast carcinoma, associated with an excellent prognosis. This highly specific immunophenotype could be useful to differentiate adenoid cystic carcinoma of the breast from other subtypes of breast carcinoma such as cribriform carcinoma.

Immunoreactivity for c-kit and p63 as an adjunct in the diagnosis of adenoid cystic carcinoma of the breast

Adenoid cystic carcinoma of the breast represents a unique clinicopathologic entity with a variable histological appearance and a relatively indolent clinical course in most of the cases. Adenoid cystic carcinoma may be difficult to differentiate from infiltrating duct carcinomas, and in particular from tubular and cribriform carcinomas, especially in core or vacuum-assisted biopsies. We evaluated the prevalence of c-kit, p63, and e-cadherin immunoreactivity in a series of 20 adenoid cystic carcinomas, comparing the results with those obtained in a series of infiltrating tubular carcinomas and infiltrating cribriform carcinomas. The hormone receptor status, proliferation labeling index, and HER/2 immunoreactivity had been previously investigated in all the cases. Three (15%) adenoid cystic carcinomas and all infiltrating tubular and cribriform carcinomas showed estrogen receptor and/or progesterone receptor immunoreactivity (P < 0.00001 for estrogen and P = 0.00002 for progesterone receptors). Adenoid cystic carcinomas consistently lacked any immunoreactivity for HER/2, whereas three (15%) infiltrating and cribriform carcinomas showed weak and incomplete membrane staining (P = 0.23077). Membranous immunoreactivity for c-kit was found in all except one (predominantly basaloid) adenoid cystic carcinomas (95%), and in none of the infiltrating tubular and cribriform carcinomas (P < 0.00001). Nuclear immunoreactivity for p63 was found in all except three (predominantly basaloid) adenoid cystic carcinomas (85%) and in none of the infiltrating tubular and cribriform carcinomas (P < 0.00001). All infiltrating tubular and cribriform carcinomas and 18/20 (90%) adenoid cystic carcinomas showed immunoreactivity for e-cadherin (P = 0.48718). In summary, adenoid cystic carcinomas showed the following phenotype: estrogen receptor-/progesterone receptor-/c-kit+/p63+ (13 cases, 65%), estrogen receptor-/progesterone receptor/c-kit+/p63- (three cases, 15%), estrogen receptor-/progesterone receptor-/c-kit-/p63+ (one case, 5%), estrogen receptor+/progesterone receptor+/c-kit+/p63+ (two cases, 10%), and estrogen receptor+/progesterone receptor-/c-kit+/p63+ (one case). By contrast, all the infiltrating tubular and cribriform carcinomas showed the estrogen receptor+/progesterone receptor+/c-kit-/p63- phenotype. Our data provide evidence that immunoreactivity for c-kit and/or p63 may be useful in differentiating adenoid cystic carcinomas from other types of breast cancer.

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.

Expression of TIMP-1 and -2 in different growth patterns of adenoid cystic carcinoma

Tissue inhibitors of metalloproteinases (TIMPs) are special inhibitors of matrix metalloproteinases. To evaluate their roles in adenoid cystic carcinoma (ACC), we compared TIMP-1 and -2 mRNA and protein expression in different histological pattern of ACC. We obtained carcinoma cells from each of cribriform and tubular pattern of ACCs using by laser microdissection (LM), to determine the mRNAs expression of TIMP-1 and -2 using by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR), and to confirm expression of them by immunohistochemical staining. Our results showed that mRNA expression of TIMP-1 tended to be decreased in cribriform pattern compared with tubular pattern in four cases, and TIMP-1 significantly decreased in three cases. TIMP-2 also significantly decreased in cribriform than in tubular pattern in three of four cases. Protein expression of TIMP-1 and -2 decreased in the cribriform pattern compared to tubular pattern. These results indicate that there is close relationship between TIMPs and growth patterns of ACC, and TIMP-1 and -2 may play important roles in morphogenesis and biological character of adenoid cystic carcinoma.

Basaloid squamous cell carcinoma of the esophagus with or without adenoid cystic features

CONTEXT

Basaloid squamous cell carcinoma (BSCC) of the esophagus is a rare malignant tumor that morphologically could bear some resemblance to adenoid cystic carcinoma (ACC) originating from salivary glands.

OBJECTIVE

The purpose of this study is to describe the histologic, immunohistochemical, and ultrastructural findings of BSCCs of the esophagus, with an emphasis on comparing tumors with or without adenoid cystic features.

DESIGN

We reviewed 239 cases of primary esophageal carcinoma and detected 12 cases (5%) of BSCC. The light and electron microscopic findings and immunocytochemical localization of various antigens, including cytokeratins (AE1, AE3), carcinoembryonic antigen, epithelial membrane antigen, S100, smooth muscle actin, and p53, were examined in these BSCC cases.

RESULTS

Histologically, all BSCCs were composed of solid lobules or nests of basaloid cells with well-demarcated outlines surrounded by a fibrous stroma. Seven of 12 tumors showed areas of ACC-like features, that is, cribriform-like pseudoglandular lumina formation and hyaline material surrounding the tumor nests, whereas the remaining 5 tumors were apparently pure basaloid carcinomas. These 2 groups of tumors were histologically and immunohistochemically identical in many aspects, namely, high-grade nuclei of the tumor cells with frequent mitoses, abundant comedo-type necrosis, focal areas of concomitant squamous differentiation, consistent immunoreactivity for cytokeratins, and poor or absent staining for S100 and smooth muscle actin. Ultrastructurally, the basaloid tumor cells exhibited relatively undifferentiated cellular characteristics and undeveloped cell organelles.

CONCLUSION

Basaloid squamous cell carcinomas of the esophagus frequently have an intimate association with ACC-like patterns, but their histologic, immunocytochemical, and ultrastructural features correspond more to poorly differentiated squamous cell carcinoma than to salivary gland ACC. This distinction is important because genuine ACC is much less aggressive than BSCC.

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.

Salivary-type neoplasms of the breast and lung

Salivary-type tumors occur in multiple sites in the human body, likely related to a basic structural homology between exocrine glands in these different anatomic areas. This paper reviews these salivary gland tumor types in breast tissue and lung. Salivary-type tumors of both breast and lung are relatively uncommon in comparison to their salivary gland counterparts. This may be attributable in part to lack of familiarity with these tumors in extra-salivary sites, and in part to histologic overlap with other primary and metastatic tumor types. Recognition of these entities is improving as the clinical and pathologic features are better delineated, and tumors are more accurately classified. Prediction of malignant behavior is not always possible in these unusual sites. In some instances, such as adenoid cystic carcinoma, behavior is known to differ considerably from that of analogous primary salivary gland tumors and in other instances there are simply too few reported cases to allow for adequate prognostication. In fact, more recent papers discuss the need to consider a spectrum encompassing benign and malignant lesions, in both breast and lung. Of course, some entities show clear-cut evidence of malignancy with documented potential for metastasis, others show bland features and well-reported benign behavior, and the less well-defined entities reside between these two extremes. The molecular pathology of salivary gland tumors has been reasonably well investigated in that location; however; there are few molecular studies devoted to salivary-type tumors of the breast and lung. This represents a potential area for future growth in further clarifying these tumors and their behavior.

Microglandular adenosis with transition into adenoid cystic carcinoma of the breast

Microglandular adenosis (MGA) is a well-recognized, if rare and incompletely characterized, entity in which carcinoma is rarely thought to develop. We report 17 cases in which patterns of adenoid cystic carcinoma (ACC) coexisted with MGA. Immunocharacterization with beta-catenin, E-cadherin, cytokeratins (AE1/AE3), epithelial membrane antigen, S-100 protein, smooth muscle actin, and vimentin was also performed. Most cases had areas of invasive ACC characterized by its defining dual-lumen types. Some cases of ACC appeared to have expanded glands intermingled within the MGA, whereas in other cases ACC formed a transition with the characteristic small, gland-like spaces of MGA. MGA and "atypical MGA" stained irregularly and similarly to that seen in myoepithelium with the three markers of myoepithelial cells in breast: S-100 protein, smooth muscle actin, and vimentin. These markers were also positive in the more solid elements of the ACC. Our study suggests that ACC may develop in a background of and in continuity with MGA. Altered myoepithelial cells appear to be the major neoplastic element in both ACC and "atypical MGA." "Atypical MGA" with transition to ACC may show histologic patterns and an immunohistochemical profile similar to that of ACC. These lesions might be best interpreted as ACC in situ. Both MGA and ACC of the breast grow in an expansile and diffusely infiltrative pattern without having significant metastatic capacity. Their unusual interaction with the surrounding stroma may play a role in this benign biologic behavior.

Multifocal ductal cell hyperplasia in the submandibular salivary glands of Wistar rats chronically treated with a novel steroidal compound

A high incidence of multifocal ductal hyperplasia was observed in the submandibular salivary gland of rats treated for 26 weeks with a high dose of a novel synthetic steroid with combined estrogenic and progestagenic properties. Hyperplastic foci consisted of microcystic duct-like structures lined by a single or multilayered epithelium, sometimes showing a tendency towards a cribiform growth pattern. The hyperplastic ducts wereembedded in a collagen-rich stroma and surrounded by numerous myoepithelial cells. Immunohistochemical methods used for the detection of estrogen- and progesterone receptors revealed that progesterone receptors were abundantly present in the nucleus of epithelial cells within the lesions, exclusively. Estrogen receptors could not be detected in both the normal tissue and hyperplasic foci. The morphological, ultrastructural, and immunohistochemical characteristics strongly suggest that these hyperplastic lesions originated from the intercalated ducts. The rodent-specific granular duct cell was not involved in the pathogenesis as was clearly demonstrated by the lack of immunoreactive epidermal growth factor within the lesions. Lesions were not observed in studies with progestagens and estrogens alone or with other combined estrogen/progestagen compounds, suggesting that the specific ratio of estrogenic and progestagenic activity of the present steroid had played an important role in the development of ductal hyperplasia in this study. Lesions of the intercalated ducts, as described in this study, have not been reported before in the literature.

Large scale molecular analysis identifies genes with altered expression in salivary adenoid cystic carcinoma

Salivary gland cancers comprise a heterogeneous group of neoplasms whose biological and clinical characteristics differ considerably from those of mucosal squamous cell carcinomas of the head and neck. One of the most common subtypes, adenoid cystic carcinoma (ACC), is notable for its myoepithelial differentiation, proclivity for hematogenous spread, and slow but progressive clinical course. The molecular alterations that underlie its development and progression are poorly characterized. Here we used oligonucleotide microarray analysis to survey the expression of 8920 different human genes in 15 ACCs, one ACC cell line, and five normal major salivary glands. We observed expression of genes indicative of myoepithelial differentiation, as expected, including those whose protein products are components of basement membranes and extracellular matrix. Other genes that were highly ranked for their expression in ACC were those encoding the transcription factors SOX4 and AP-2 gamma, the latter of which also was overexpressed in ACC relative to 175 other carcinomas from 10 anatomical sites that we had previously profiled. Additional genes, which were highly expressed in ACC compared to the other carcinomas, included casein kinase 1, epsilon and frizzled-7, both members of the Wnt/beta-catenin signaling pathway. Our study documents for the first time the diverse spectrum of genes overexpressed in ACC and highlights gene products and pathways that in the future might be exploited as therapeutic targets for this cancer, which up until now, has shown limited response to chemotherapeutic approaches.

Solid variant of mammary adenoid cystic carcinoma with basaloid features: a study of nine cases

Adenoid cystic carcinoma of the breast is a rare neoplasm that represents <1% of breast carcinomas. The tumors are histologically indistinguishable from examples in other sites, and they have a generally favorable prognosis. Several studies have investigated the possible correlation between histologic grade in adenoid cystic carcinoma (largely determined by cytology and growth pattern) and prognosis. Some earlier reports concluded that a solid variant of mammary adenoid cystic carcinoma had a more aggressive clinical course, but others did not confirm this impression. This report describes nine patients with a solid variant of mammary adenoid cystic carcinoma that has a striking basaloid appearance. All were women ranging in age from 37 to 83 years. A solitary mass was evident in all patients. Tumor size was 1.1-15 cm (mean 3.7 cm). The tumors exhibited a predominantly solid architecture comprised of basaloid appearing cells with moderate to marked nuclear atypia. Five tumors had >5 mitotic figures per 10 high power microscopic fields. Intercalated ducts were found in all tumors, being well formed in six and poorly formed in three. Immunohistochemical stains for cytokeratins, basement membranes, and vimentin were consistently positive. Surgery was performed in all cases consisting of excision in seven and mastectomy in two. Axillary lymph node metastases were found in two of six axillary dissections and four had negative lymph nodes. The lymph nodes were not examined in three patients. Follow-up information was available for seven patients. Six women had no evidence of disease after follow-up of 2-88 months (mean 32 months), one patient died of unknown causes, and one patient was lost to follow-up. It is concluded that the solid variant of mammary carcinoma with basaloid features is a histologically distinct tumor that is capable of axillary metastases. Long-term follow-up of a larger series of cases will be needed to determine whether the prognosis of these patients differs significantly from that of women with conventional adenoid cystic carcinoma. Presently, these patients are candidates for axillary staging by sentinel lymph node mapping or low axillary dissection if there is no clinical evidence of axillary metastases. Systemic adjuvant treatment would be prudent when axillary nodal metastases are present. Breast-conserving surgery with radiation is an option if negative margins can be achieved because this appears to be a unicentric form of carcinoma.

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.

Expression of the c-kit protein is associated with certain subtypes of salivary gland carcinoma

The c-Kit protein, a receptor type tyrosine kinase that plays an important role in the development of hematopoietic cells, melanocytes, and germ cells, is expressed in mastocytosis, gastrointestinal stromal cell tumors (GISTs), germ cell tumors, and several other tumors. Gain-of-function mutations in exon 11 and exon 17 have been shown as a mechanism of c-kit activation in some tumors. To study the role of c-kit in salivary gland carcinomas, we analyzed the c-kit protein expression in 79 carcinomas of major and minor salivary glands by immunohistochemistry. Although varying in intensity of staining, c-kit expression was identified very often in adenoid cystic carcinomas (20/25), lymphoepithelioma-like carcinomas (6/6) and myoepithelial carcinomas (2/2), but not in other types of salivary gland carcinoma (0/46), P<0.00001. By DNA sequencing, genetic alteration of c-kit juxtamembrane domain (exon 11) and tyrosine kinase domain (exon 17) was not found in all the three types of salivary carcinoma that had c-kit protein expression. In conclusion, c-kit protein overexpression is involved in the pathogenesis of certain types of salivary gland carcinoma, but mutation of the gene is not the mechanism of c-kit activation.