Sclerosing polycystic adenosis of major salivary glands. A clinicopathologic analysis of nine cases

Update of newly-recognized salivary gland neoplasms: molecular and immunohistochemical findings and clinical importance

With the advancement of molecular testing and the routine use of immunohistochemical stains, salivary gland tumours previously categorized as adenoma or adenocarcinoma, not otherwise specified, are being reclassified with distinct diagnoses. Newly recognized benign entities include: sclerosing polycystic adenoma, keratocystoma, intercalated duct hyperplasia and adenoma, and striated duct adenoma. Newly recognized malignant salivary gland tumours include: microsecretory adenocarcinoma, sclerosing microcytic adenocarcinoma, and mucinous adenocarcinoma. Additionally, rare subtypes of mucoepidermoid carcinoma have been described, including Warthin-like and oncocytic. Understanding of intraductal carcinoma continues to evolve. Correctly distinguishing these lesions from mimickers can be crucial for appropriate patient care and prognostication, as well as future conceptualization of salivary disease.

A Case of Sclerosing Polycystic Adenoma of the Parotid Gland

Sclerosing polycystic adenoma (SPA) is a rare salivary gland tumor with about 100 cases reported in the literature. We describe a case of SPA in the parotid gland and review the diagnostic tools used for identifying SPA. A 24-year-old male with a two-year history of right-sided face mass, initially thought to be pleomorphic adenoma of the parotid gland after fine needle aspiration (FNA). Following superficial parotidectomy, histologic features were consistent with SPA. This case illustrates the challenge of pre-operative assessment for SPA. Recent study has suggested SPA is a neoplasm and definitive treatment is surgical excision.

New Entities and Concepts in Salivary Gland Tumor Pathology: The Role of Molecular Alterations

CONTEXT.—

Salivary gland tumors are rare tumor types for which the molecular understanding has resulted in a rapid expansion and shuffling of entities. These changes are reflected in the 5th edition World Health Organization Classification of Head and Neck Tumours (WHO 5th edition), although many nuances still remain.

OBJECTIVE.—

To review how molecular alterations have helped recategorize, justify, and reinstate entities into our lexicon as well as defining interrelationships between categories, new entities, and subtypes. Furthermore, newer theranostic applications to molecular phenotype will be summarized.

DATA SOURCES.—

World Health Organization Classification of Head and Neck Tumours (WHO 3rd through 5th editions), literature review, and personal and institutional experience.

CONCLUSIONS.—

Molecular alterations have helped reclassify, retain, and create new categories by augmenting rather than replacing standard criteria. Key entities that have emerged include sclerosing polycystic adenoma, microsecretory adenocarcinoma, and mucinous adenocarcinoma. Molecular phenotypes solidify the range of morphology in established entities such as mucoepidermoid carcinoma and facilitate connectivity between entities. Molecular characteristics now allow for targeted therapeutic approaches for secretory carcinoma and adenoid cystic carcinoma.

A challenging case of sclerosing polycystic adenoma of the parotid gland: a case report and brief review of the latest updates

Sclerosing polycystic adenoma (SPA) is a rare neoplastic salivary gland lesion with only about 100 cases reported worldwide so far. The lesion is confused with several malignant and other benign tumors such as apocrine intraductal carcinoma (IC), salivary duct carcinoma (SDC), chronic sclerosing sialadenitis, polycystic dysgenetic disease (PDD), pleomorphic adenoma (PA), acinic cell carcinoma (ACC), and mucoepidermoid carcinoma (MEC). We present a case of SPA for a 23-year-old male patient presenting with a slowly growing parotid mass. Fine needle aspiration (FNA) followed by total excision of the tumor was performed and the picture was consistent with SPA. We discuss the findings of the case and briefly review the literature on SPA.

What is the impact of previous cholelithiasis on sialolithiasis: A systematic review and meta-analysis

Introduction

A sialolith is a salivary stone usually presenting with swelling and pain in the affected salivary gland, most commonly the submandibular gland. There have been speculations about the association between this condition and other systemic diseases, especially those forming stones, such as nephrolithiasis and cholelithiasis. This systematic review and meta-analysis aimed to summarize the studies assessing the relationship between cholelithiasis and sialolithiasis.

Methods

PubMed/MEDLINE, Scopus, Web of Science, and Embase electronic databases were searched according to the keywords related to both disorders without any publication date or language restriction. Case-control and cohort studies evaluating the relationship between salivary and biliary stones were considered eligible. Quality assessment was performed following Newcastle-Ottawa Scale (NOS) for quality assessment of case-control studies. All meta and statistical analyses were performed with Comprehensive Meta-Analysis software.

Results

Two studies fully complied with the defined eligibility criteria and were included, both of which were case-control studies using national-scale databases. In both surveys, the prevalence of previous gallstones in patients with sialolithiasis was compared to that of a control group. Though one of the studies found that there is no relationship between sialolithiasis and cholelithiasis, the meta-analysis revealed that previous cholelithiasis is significantly more prevalent among patients with sialolithiasis (P = 0.000), with an odds ratio of 2.04.

Conclusion

It seems that cholelithiasis is significantly associated with an increase in salivary stone formation. Therefore, a thorough salivary examination in all patients declaring current or past cholelithiasis is recommended. However, more studies, especially prospective cohorts, are needed to make firmer conclusions.

Salivary gland pathologies: evolution in classification and association with unique genetic alterations

PURPOSE

The correct classification of salivary gland pathologies is crucial for choosing a treatment method and determining the prognosis. Better outcomes are now achievable thanks to the introduction of new therapy approaches, such as targeted therapies for malignant salivary gland tumors. To apply these in clinical routine, a clear classification of the lesions is required.

METHODS

The following review examines all changes from the first World Health Organization (WHO) Classification of salivary gland pathologies from 1972 to fifth edition from 2022. Possible developments in the diagnosis and classification of salivary gland pathology are also presented.

RESULTS

The current WHO classification is the fifth edition. With the development of new diagnostic methods, based on genetic alterations, it provides insight into the molecular basis of lesions. This has resulted in the evolution of classification, introduction of new entities and reclassification of existing ones.

CONCLUSIONS

Genetic alterations will become increasingly more significant in the identification of salivary gland pathologies in the future. These alterations will be helpful as prognostic and predictive biomarkers, and may also serve as targets for anti-cancer therapies.

PIK3R1, HRAS and AR Gene Alterations Associated with Sclerosing Polycystic Adenoma of the Parotid Gland

Sclerosing polycystic adenoma (SPA) is a rare neoplasm occurring in the salivary glands, mainly the parotid gland. Although it was originally thought to represent a non-neoplastic process, recent genetic data have proven its monoclonality, supporting its neoplastic origin. We report a case of a 73-year-old woman who presented with left neck swelling and pain. A 3 cm hypoechoic, heterogeneous, solid mass was identified on neck ultrasonography within the left parotid gland. Fine needle aspiration revealed benign acinar cells and lymphocytes. Left partial superficial parotidectomy was performed and a diagnosis of SPA was made. Targeted next-generation sequencing (NGS) revealed three clinically significant alterations in the PIK3R1, HRAS, and AR genes. Alterations in the PIK3R1 gene have been previously reported in cases of SPA; however, this study is the first to report two novel clinically significant genomic alterations in the HRAS and AR genes. AR protein expression by immunohistochemistry was strongly and diffusely positive in the neoplastic epithelial cells compared to the adjacent normal salivary gland tissue, which was dead negative for AR. This molecular profile will enhance our understanding of the molecular pathways underlying the development of this tumor. Although this entity was initially thought to be a reactive process, evidence from our case and similar cases strongly support the notion that it is neoplastic due to the presence of specific genetic alterations linked to it.

Sclerosing polycystic adenosis arising in the parotid gland with trismus: a case report and literature review

Sclerosing polycystic adenosis (SPA) is a rare, asymptomatic disease that occurs mainly in the salivary glands. We report the case of a 51-year-old man who presented with trismus and pain upon mouth opening. Magnetic resonance imaging revealed a 2-cm mass located in the anterior portion of the left parotid gland. SPA was diagnosed based on histopathological examination of the surgical specimen. In pathologic findings, there was a well-circumscribed multicystic nodule in the parenchyma. Dense fibrosis and chronic non-specific inflammatory cells were observed in the stroma. In 13 previous reports on SPA, the most preferred treatment was superficial or total parotidectomy. This report suggests that simple excision of SPA preserves facial nerve function and facial volume.

Sclerosing Polycystic Adenoma: Conclusive Clinical and Molecular Evidence of Its Neoplastic Nature

Sclerosing polycystic adenosis, initially considered a non-neoplastic salivary gland lesion and classified as such in the 2017 WHO Classification of Head and Neck Tumors, has been the subject of controversy regarding its possible neoplastic nature. The reporting of recurrent PI3K pathway alteration represents evidence to support these lesions as being neoplastic and more appropriately referred to as sclerosing polycystic adenoma (SPA). Herein, we provide additional evidence that supports the classification of SPA as a true neoplasm. Eight cases of SPA were identified in our database and consultation files. All cases were subjected to PTEN immunohistochemistry (IHC) and next-generation sequencing (NGS). In addition, one patient underwent genetic counseling and germline testing. The cases included 5 men and 3 women with a mean age of 41 years (range 11-78) and all tumors arose in the parotid gland. One patient had multiple recurrences over a period of 2 years. Morphologically the tumors were circumscribed and characterized by an admixture of acini, ducts and cysts embedded in a fibrotic/sclerotic stroma. The cells lining the ducts and cysts showed variable granular, vacuolated, foamy and apocrine cytoplasmic features, as well as acinar cells contained intracytoplasmic brightly eosinophilic granules. The apocrine intraductal proliferations showed mild to moderate atypia in 6 cases. One case showed overt malignant morphology that ranged from intraductal carcinoma to invasive salivary duct carcinoma. Seven cases tested for PTEN IHC showed loss of nuclear expression in the acinar and ductal cells with retained PTEN expression in the myoepithelial cell and stroma. NGS detected PIK3CA or PIK3R1 genetic alterations in 7 cases, including a novel TFG-PIK3CA fusion. Coexisting PTEN mutations were seen in 4 cases, including in a patient with clinical stigmata of Cowden syndrome and confirmed by germline genetic testing. Our findings herein documented including recurrence of tumor, malignant transformation, high prevalence of PI3K pathway oncogenic alterations and the possible heretofore undescribed association with Cowden syndrome add support to classifying SPA as true neoplasms justifying their designation as adenoma, rather than adenosis.

Sclerosing Polycystic Adenoma of Salivary Glands: A Novel Neoplasm Characterized by PI3K-AKT Pathway Alterations-New Insights Into a Challenging Entity

Sclerosing polycystic adenoma (SPA) is a rare salivary gland neoplasm originally thought to represent a non-neoplastic lesion. Recently we have encountered an index case of apocrine intraductal carcinoma of parotid gland of 62-year-old man with invasive salivary duct carcinoma component arising from SPA, a combination of tumor entities that has never been published so far. Here, we further explore the nature of SPA by evaluating 36 cases that were identified from the authors' consultation files. The patients were 25 females and 11 males aged 11 to 79 years (mean, 47.8 y). All tumors originated from the parotid gland. Their size ranged from 11 to 70 mm (mean, 28 mm). Histologically, all cases revealed characteristic features of SPA, such as lobulated well-circumscribed growth, focal hyalinized sclerosis, presence of large acinar cells with abundant brightly eosinophilic intracytoplasmic granules, and ductal components with variable cytomorphologic characteristics, including foamy, vacuolated, apocrine, mucous, clear/ballooned, squamous, columnar and oncocyte-like cells. In all cases, there were foci of intraluminal solid and cribriform intercalated duct-like epithelial proliferations with variable dysplasia which were positive for S100 protein and SOX10, and fully enveloped by an intact layer of myoepithelial cells. In addition, 14/36 cases (39%) had focal intraductal cribriform and micropapillary apocrine-type dysplastic epithelial structures composed of cells positive for androgen receptors and negative for S100/SOX10. The intraductal proliferations of both types showed focal mild to severe dysplasia in 17 cases (17/36; 47%). Two cases showed overt malignant morphology ranging from high-grade intraductal carcinoma to invasive carcinoma with an apocrine ductal phenotype. Next generation sequencing using ArcherDX panel targeting RNA of 36 pan-cancer-related genes and/or a TruSight Oncology 170/500 Kit targeting a selection of DNA from 523 genes and RNA from 55 genes was performed. Tumor tissue was available for molecular analysis in 11 cases, and 9 (9/11; 82%) of them harbored genetic alterations in the PI3K pathway. Targeted sequencing revealed HRAS mutations c.37G>C, p.(Gly13Arg) (2 cases) and c.182A>G, p.(Gln61Arg) (2 cases), and PIK3CA mutations c.3140A>G, p.(His1047Arg) (3 cases), c.1633G>A, p.(Glu545Lys) (1 case), and c.1624G>A, p.(Glu542Lys) (1 case). Moreover, mutations in AKT1 c.49G>A, p.(Glu17Lys) and c.51dup, p.(Tyr18ValfsTer15); c.49_50delinsAG, p.(Glu17Arg) (as a double hit) were found (2 cases). In addition, germinal and somatic mutation of PTEN c.1003C>T, p.(Arg335Ter); c.445C>T, p.(Gln149Ter), respectively, were detected. Gene fusions were absent in all cases. These prevalent molecular alterations converging on one major cancer-related pathway support the notion that SPA is a true neoplasm with a significant potential to develop intraluminal epithelial proliferation with apocrine and/or intercalated duct-like phenotype. The name SPA more correctly reflects the true neoplastic nature of this enigmatic lesion.

Sclerosing Polycystic Adenosis Arising in the Parotid Gland Without PI3K Pathway Mutations

A 15-year-old old Japanese male with a 2-month history of swelling of his left subauricular area was admitted to our department. A thumb-sized, hard mass with mild tenderness was palpated on the left parotid gland. Ultrasonography revealed a well-circumscribed, hypoechoic mass exhibiting heterogeneity in the left parotid gland measuring 1.7 × 1.5 × 1.3 cm. Computed tomography scan revealed a well-circumscribed, solid mass exhibiting slight peripheral enhancement in the left parotid gland. Magnetic resonance imaging revealed a hypointense mass in the left parotid gland on both T1- and T2-weighted images. Clinicoradiologic findings suggested a benign or low-grade malignant parotid tumor. The patient underwent left superficial parotidectomy with adequate safety margins. The facial nerve was identified and preserved. Neither facial paralysis nor tumor recurrence was observed as of 1 year postoperatively. Histologically, the nodule consisted of a vaguely nodular arrangement of variably sized ducts and acini in a hyalinized fibrous background with focal myxoid changes. The ductal/acinar component exhibited a bilayered arrangement of cuboidal luminal and flattened abluminal cells exhibiting a variety of epithelial proliferative patterns, including micropapillary and cribriform. Areas of oncocyte-like changes with intracellular coarse eosinophilic granules, apocrine-like feature, foamy/vacuolated changes, and clear cells were noted in the proliferating epithelium. Immunohistologically, the luminal cells were positive for gross cystic disease fluid protein-15. The Ki-67 labeling index was 2-3%. The histologic features and immunohistologic profile were consistent with sclerosing polycystic adenosis. Targeted next-generation sequencing of 160 cancer-related genes using the surgical specimen revealed no mutations, including known significant mutations in PTEN, PIK3CA, or PIK3R1.

Sclerosing polycystic adenosis of the submandibular gland: Two case reports

BACKGROUND

Sclerosing polycystic adenosis (SPA) is a rare disease of salivary glands, similar to fibrocystic disease of the breast. It occurs over a wide age range and exhibits a slight female preference. Most SPA cases have occurred in the parotid gland. The exact nature of SPA is unclear, but its tumor nature has recently been proposed. Although SPA has a good prognosis after adequate surgery, atypical lesions might occur, ranging from mild dysplasia to carcinoma in situ in some cases. To the best of our knowledge, only five cases of SPA in the submandibular gland have been reported to date. Here, we present two new cases of SPA involving the submandibular gland.

CASE SUMMARY

A 50-year-old woman and a 52-year-old woman were referred to Tongji Hospital in Wuhan, China, with complaints of moderate pain, recurrent swelling, and a mass in the submandibular area. After admission, the two cases of the submandibular mass were examined physically. The boundary of the submandibular tumor was clear, and the range of motion was good. After preoperative examinations, surgery was performed on a selective basis. Postoperative histopathological examination revealed a well-defined mass with acinar structures, ducts, or cystic dilated glands of various sizes scattered in a large number of proliferative sclerosing stroma. There were flat and cuboidal cells, and eosinophils in the duct epithelium. There was also a eosinophilic substance in the lumen of dilated cysts. No atypical epithelial hyperplasia, invasive growth, or carcinoma in situ was found. Based on the above findings, the mass was diagnosed as SPA. Both patients have remained asymptomatic and no recurrence or distant metastasis had occurred by the 7-mo and 5-year follow-up, respectively.

CONCLUSION

SPA is a rare disease of the salivary gland. Even though it has a good prognosis after adequate surgery, atypical lesions may occur from mild dysplasia to carcinoma in situ. However, no recurrence, distant metastasis, or mortality has been reported for submandibular gland SPA. Clinicians and pathologists should be familiar with the characteristics of SPA in the submandibular gland to avoid misdiagnosis and overtreatment.

Sclerosing Polycystic Adenoma

Sclerosing polycystic adenoma (SPA) is the more appropriate name for sclerosing polycystic adenosis. SPA is an uncommon salivary gland lesion with a constellation of unusual histologic findings that were originally interpreted as analogous to breast fibrocystic changes. The histologic findings in SPA include fibrosis, cystic alterations, apocrine metaplasia, and proliferations of ducts, acini, and myoepithelial cells in variable proportions. Because of its unusual mixed histology, SPA may be confused with a variety of lesions, ranging from reactive conditions to benign or even malignant neoplasms. The features of SPA are reviewed, with an emphasis on resolving its differential diagnosis.

Sclerosing Polycystic "Adenosis" of Salivary Glands: A Neoplasm Characterized by PI3K Pathway Alterations More Correctly Named Sclerosing Polycystic Adenoma

Sclerosing polycystic adenosis (SPA) is a rare benign salivary gland lesion that usually arises from the parotid gland. SPA was originally interpreted to be a non-neoplastic alteration analogous to fibrocystic changes of the breast, but now there is uncertainty about whether it may represent a neoplasm. SPA often contains intraductal proliferations with an appearance similar to ductal neoplasia of the breast, and one study reported X-chromosome inactivation using polymorphisms of the human androgen receptor (Skalova et al., in AJSP 30:939-944, 2006). We investigated the genetics of SPA through targeted next generation sequencing (NGS). Four cases of SPA were retrieved from the authors' consultation files. A custom, targeted NGS panel including 1425 cancer-related genes was performed on all cases, followed by immunohistochemistry for PTEN. All four cases developed in females, ranging from 40 to 69 years (mean 52.5 years), affecting the parotid (n = 3) and submandibular glands (n = 1). All cases exhibited characteristic histologic features of SPA: well-circumscribed lesions with fibrosis and an admixture of ducts, myoepithelial cells and acinar cells, the latter containing brightly eosinophilic intracytoplasmic granules. Two cases had intraductal apocrine epithelial proliferations. By targeted NGS, loss-of-function mutations in PTEN were revealed in all 4 cases. In addition, 2 of 4 cases harbored PIK3CA mutations and 2 of 4 possessed PIK3R1 alterations; one case lacked both PIK3CA and PIK3R1 mutations. PTEN expression by immunohistochemistry was lost in the ductal and acinar elements but not the myoepithelial cells in all cases. SPA is characterized by genetic alterations in the PI3K pathway, with PTEN mutations seen most frequently. This molecular profile is similar to salivary duct carcinoma and the apocrine variant of intraductal carcinoma (i.e., salivary duct carcinoma-in situ). PI3K pathway alterations were found in cases both with and without intraductal apocrine proliferations, and PTEN immunohistochemistry suggested that the ductal and acinar cells, but not myoepithelial cells, were affected. Taken together, these findings strongly support that SPA is a neoplasm, more correctly named "sclerosing polycystic adenoma." The salivary duct carcinoma-like genetic alterations, coupled with the fact that the surrounding myoepithelial cells appear to be non-neoplastic, suggest a close relationship between SPA and apocrine intraductal carcinoma.

Juvenile sclerosing polycystic adenosis cytologically mimicking Warthin tumor

Sclerosing polycystic adenosis (SPA) is a rare salivary gland disease. Histologically it resembles a low-grade ductal carcinoma in situ or sclerosing adenosis of the breast, characterized by lobular proliferation of ducts with apocrine cellular features surrounded by fibrosclerotic stroma. Although SPA is typically benign, recurrence is not uncommon, and cases with a malignant component have been documented. Thus, complete excision is desirable but preoperative diagnosis is challenging. A 12-year-old boy presented with a painless mass in the right neck. We identified a well-demarcated mass in the right parotid region measuring approximately 2 cm using cervical echography and magnetic resonance (MR) imaging. Fine-needle aspiration (FNA) revealed two cell types. There were loosely cohesive clusters of polymorphic epithelioid cells with irregular nuclei and abundant vacuolated cytoplasm containing zymogen granules. Some of these cells were binuclear. The other cell types represented normal ductal cells. The original cytological diagnosis was Warthin tumor. Right parotidectomy was performed. Histologically, we observed proliferation of ducts with granular, vacuolated, zymogen granules, and apocrine-like features in the cytoplasm with hyalinizing sclerotic stroma and some binuclear cells. Four years after parotidectomy, there has been no recurrence or malignant transformation.Cytological diagnosis of SPA is challenging on FNA specimens since SPA is a very rare entity of the salivary gland that can mimic other salivary gland neoplasms. A mixture of apocrine-like cells and sebaceous-like cells, nuclear pleomorphism, and zymogen granules can help to diagnose this rare lesion during the initial cytological diagnosis.

Sclerosing Polycystic Adenosis of Tongue

Sclerosing polycystic adenosis (SPA) is a rare benign lesion of the salivary glands which appears histologically similar to sclerosing adenosis and fibrocystic disease of the mammary gland. To date, 67 cases of SPA have been reported in the literature, with the lesion arising in the minor salivary glands in only 9. The present report describes the 10th case of SPA. The patient was a 39-year-old Brazilian man who presented with an asymptomatic nodule on the ventral surface of the tongue. Based on a clinical diagnosis of benign salivary gland neoplasm, an excisional biopsy of the lesion was performed. Histopathological examination showed lobular proliferation of ductal and acinar elements surrounded by a fibrosclerotic stroma. Many of the ductal structures exhibited cystic dilatation and were surrounded by periductal fibrosis, which is consistent with SPA findings. No recurrence of the disease was observed after a 5-year follow-up. A literature review is also discussed, focusing on both the etiology of SPA and the treatment options available.

Sclerosing Polycystic Adenosis of Hard Palate: A Rare Entity in Salivary Glands

Sclerosing polycystic adenosis (SPA) is a rare neoplasm of salivary glands, with a striking resemblance to the benign fibrocystic disease of the breast. The most common site of occurrence is the parotid gland. However, submandibular gland, minor salivary glands, and buccal mucosa may also be affected. It shows a slight female predilection and occurs over a wide age range. The exact nature of the disease is unknown but is postulated to be a neoplasm recently. The treatment is effective by localized surgical excision, and recurrence is rare. To the best of our knowledge, there is only one case report of SPA involving palate. Here, we describe an additional case report of SPA occurring in the palatal region of a 49-year-old male patient.

Non-cystic Sclerosing Polycystic Adenosis: Diagnosis of a Hitherto Undescribed Pattern

A case of sclerosing polycystic adenosis without cysts is described. The lesion occurred as a painless slow growing superficial right parotid lump in a 47 years old woman. The tumor measured 14 × 10 mm and displayed extreme well circumscription, sclerotic stroma with scattered hyaline nodules, sprinkling of mononuclear inflammatory cells and islands of mature fat. The epithelial component was predominantly composed of tubules lined by low columnar to cuboidal epithelium with bland nuclear features. Only focal incomplete acinar differentiation with few cells containing small eosinophilic granules was present. The stroma contained a significant fibromyxoid component with increased cellularity. There was no recurrence on follow-up at 14 months.

Imaging of Inflammatory Disorders of Salivary Glands

Sialadenitis is among the most common conditions that affect the salivary glands. Inflammation of the salivary glands occurs as the end result of a variety of pathologic conditions, including infectious, autoimmune, and idiopathic causes. Clinically, inflammation of the salivary gland causes pain and localized swelling. The presentation may be acute or chronic, and can be recurrent. Because there is significant overlap of underlying disease mechanisms and clinical presentations, radiologic evaluation often plays a significant role in evaluation. This article is a brief review of sialadenitis, including disease mechanisms, causes, and the practical imaging of the salivary glands.

Sclerosing polycystic adenosis of the oral cavity

Minor salivary glands are ubiquitous in the oral cavity, and related diseases are often indolent and asymptomatic. We describe the unusual features of sclerosing polycystic adenosis, and its similarities to more sinister conditions of the minor salivary glands. Its importance is currently uncertain and research points to a pathogenesis that is neoplastic, which can create ambiguity. Sclerosing polycystic adenosis is a newly-discovered condition that merits further discussion and research to evaluate its full impact.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumors of the Salivary Gland

The salivary gland section in the 4th edition of the World Health Organization classification of head and neck tumors features the description and inclusion of several entities, the most significant of which is represented by (mammary analogue) secretory carcinoma. This entity was extracted mainly from acinic cell carcinoma based on recapitulation of breast secretory carcinoma and a shared ETV6-NTRK3 gene fusion. Also new is the subsection of "Other epithelial lesions," for which key entities include sclerosing polycystic adenosis and intercalated duct hyperplasia. Many entities have been compressed into their broader categories given clinical and morphologic similarities, or transitioned to a different grouping as was the case with low-grade cribriform cystadenocarcinoma reclassified as intraductal carcinoma (with the applied qualifier of low-grade). Specific grade has been removed from the names of the salivary gland entities such as polymorphous adenocarcinoma, providing pathologists flexibility in assigning grade and allowing for recognition of a broader spectrum within an entity. Cribriform adenocarcinoma of (minor) salivary gland origin continues to be divisive in terms of whether it should be recognized as a distinct category. This chapter also features new key concepts such as high-grade transformation. The new paradigm of translocations and gene fusions being common in salivary gland tumors is featured heavily in this chapter.

Newly described salivary gland tumors

This review concentrates on three salivary gland tumors that have been accepted in the recent literature as new neoplastic entities: mammary analog secretory carcinoma (MASC), sclerosing polycystic adenoma (SPA) and cribriform adenocarcinoma of tongue and other minor salivary glands (CAMSGs). MASC is a distinctive low-grade malignant salivary cancer that harbors a characteristic chromosomal translocation, t(12;15) (p13;q25) resulting in an ETV6-NTRK3 fusion. SPA is a rare lesion often mistaken histologically for low-grade salivary carcinoma. Previously thought to be a reactive fibroinflammatory process, but recent evidence of clonality, recurrences in up 30%, and dysplastic foci suggest it may be truly neoplastic. CAMSG is a distinct tumor entity that differs from polymorphous low-grade adenocarcinoma (PLGA) by location (ie, most often arising on the tongue), by prominent nuclear clearing, alterations of the PRKD gene family and clinical behavior with frequent metastases at the time of presentation of the primary tumor. Early metastatic disease seen in most cases of CAMSG associated with indolent behavior makes it a unique neoplasm among all low-grade salivary gland tumors. Salivary glands may give rise to a wide spectrum of different tumors. They are often diagnostically challenging as morphological features often overlap between different entities. Although conventional morphology in combination with immunohistochemical findings still provide the most important clues for diagnosis, recent advances in molecular pathology offer new diagnostic tools in investigating the differential diagnosis, as well as providing potentially valuable prognostic indicators. In the last two decades, several new salivary gland tumor entities have been described, namely MASC, SPA and CAMSGs.

Sclerosing Polycystic Adenosis of the Parotid Gland: A Systematic Review and Report of 2 New Cases

PURPOSE

We sought to evaluate clinical-epidemiologic aspects, pathologic characteristics, and treatment of sclerosing polycystic adenosis (SPA) of the parotid gland and to report 2 new cases.

MATERIALS AND METHODS

We conducted a systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for studies published in or before June 2016. The inclusion criteria were as follows: final diagnosis of SPA affecting the parotid gland and articles published in Spanish or English. The exclusion criteria were as follows: unclear diagnosis after pathologic analysis and patients affected by other conditions in the major salivary glands. We added 2 new cases.

RESULTS

Our review ultimately included 21 articles and 45 cases. The mean patient age was 41 years (range, 7-84 years). The female-to-male ratio was 2:1. In all patients the tumor showed progressive growth. The evolution range was 7 days to 11 years. In 17.7% of cases, the tumor was associated with pain. The average tumor size was 30.3 mm (range, 12-60 mm). Fine needle aspiration biopsy (FNAB) was unable to diagnose 30 cases. Benign tumors comprised 58% of tumors (18), whereas malignancy was present in 25.8% (8). Thirty-five tumors were well circumscribed. There were 8 multinodular or lobed cases. The tumor was described as encapsulated in 1 case, partially encapsulated or pseudo-encapsulated in 16, and not encapsulated in 12. Five cases showed different degrees of degenerative changes, ranging from dysplasia to invasive carcinoma. All cases underwent surgical treatment. Superficial parotidectomy with preservation of the facial nerve was performed in 22 cases (61.1%), total parotidectomy in 8 (22.2%), and tumor enucleation in 6 (16.6%). The mean follow-up period was 51.5 months (range, 5-276 months). Of documented cases, 74.2% had 2 or more years of follow-up. Recurrences occurred in 6 cases (16.6%).

CONCLUSIONS

We consider SPA a benign tumor with progressive growth, which is occasionally painful. It occurs around age 40 years and occurs more often in female patients. Fine needle aspiration biopsy does not provide an adequate preoperative diagnosis. Recurrences are infrequent. Follow-up should be customized according to the pathologic findings. Malignant transformation may occur. Superficial parotidectomy with facial nerve preservation is the treatment of choice.

Surgical Treatment of Rare Sclerosing Polycystic Adenosis of the Deep Parotid Gland

We experienced a rare case of sclerosing polycystic adenosis (SPA) arising in a parotid gland. A 33-year-old man who underwent unspecified surgery for a lesion in the left parotid gland 23 years ago presented with a lesion on the same site. Computed tomography scan revealed an encapsulated 3 × 2 cm lesion. Intraoperative findings showed that the tumor was embedded deep in the parotid gland. Marginal tumor excision was performed to preserve the facial nerve. Histopathological and immunohistochemical findings led to the final diagnosis of SPA. The surgery was not associated with any other complications. To date, 28 months after surgery, recurrence has not been observed. The treatment protocol of SPA has not yet been established. To make plastic surgeons familiar with this disease, we describe this case, which was successfully treated without any complications.

Sclerosing Polycystic Adenosis: A Rare Tumor of the Salivary Glands

CASE PRESENTATION

A 74-year-old woman presented to the Head and Neck Surgery clinic with a 4-year history of a slowly growing, painful, left-sided neck mass in the tail of the parotid gland. Fine-needle aspiration suggested well-differentiated adenocarcinoma.

DISCUSSION AND RESULTS

The patient underwent a superficial parotidectomy and super-selective neck dissection (level 2). Pathology revealed a tumor consistent with sclerosing polycystic adenosis.

CONCLUSION

Sclerosing polycystic adenosis is a rare inflammatory process that causes fibrocystic changes in the salivary gland. Apocrine-like metaplasia and epithelial atypia are common pathologic features. To our knowledge, a total of 51 cases have been described in the English-language literature.

Salivary gland disorders

Patients with salivary gland disease present with certain objective and/or subjective signs. An accurate diagnosis for these patients requires a range of techniques that includes the organized integration of information derived from their history, clinical examination, imaging, serology, and histopathology. This article highlights the signs and symptoms of the salivary gland disorders seen in the Salivary Gland Center, and emphasizes the methodology used to achieve a definitive diagnosis and therapy.

Salivary gland tumor "wishes" to add to the next WHO Tumor Classification: sclerosing polycystic adenosis, mammary analogue secretory carcinoma, cribriform adenocarcinoma of the tongue and other sites, and mucinous variant of myoepithelioma

This review is a continuation of suggested tumor additions to the next WHO Tumor Classification. The author will focus on four salivary gland entities that have recently become accepted in the literature as new neoplastic entities: sclerosing polycystic adenosis, mammary analogue secretory carcinoma, cribriform adenocarcinoma of the tongue and other sites, and mucinous variant of myoepithelioma.

Invasive carcinoma arising from sclerosing polycystic adenosis of the salivary gland

Sclerosing polycystic adenosis is a rare salivary gland lesion. Recently, this entity has been regarded as a neoplastic lesion of low-grade malignant potential but, to date, no invasive carcinoma, metastases, or associated mortality have been reported. We report the first case of an invasive carcinoma component in a recurrent sclerosing polycystic adenosis lesion.

Sclerosing polycystic adenosis of parotid gland: a unique report of two cases occurring in two sisters

Sclerosing polycystic adenosis (SPA) of salivary glands is a tumorous lesion of salivary glands, with clinical presentation of a slow-growing mass characterized by a combination of histological features, some of which are reminiscent of mammary fibrocystic disease. SPA is mostly unifocal, but rarely may be multifocal and/or bilateral. Recurrences have been reported in up to 19% of cases. Although originally considered pseudoneoplastic, the occurrence of "dysplasia" and carcinoma in situ of ductal epithelium, and recent evidence of clonality suggest a possible neoplastic nature. Herein we describe, for the first time, two cases of SPA in two sisters (7 and 33 years old). The younger patient experienced multiple recurrences. This is the first report of familial occurrence of SPA, suggesting a possible genetic background.

Low-grade salivary duct carcinoma or low-grade intraductal carcinoma? Review of the literature

Low-grade salivary duct carcinoma (LG-SDC) is a rare neoplasm characterized by predominant intraductal growth, luminal ductal phenotype, bland microscopic features, and favorable clinical behavior with an appearance reminiscent of florid to atypical ductal hyperplasia to low grade intraductal breast carcinoma. LG-SDC is composed of multiple cysts, cribriform architecture with "Roman Bridges", "pseudocribriform" proliferations with floppy fenestrations or irregular slits, micropapillae with epithelial tufts, fibrovascular cores, and solid areas. Most of the tumor cells are small to medium sized with pale eosinophilic cytoplasm, and round to oval nuclei, which may contain finely dispersed or dark condensed chromatin. Foci of intermediate to high grade atypia, and invasive carcinoma or micro-invasion have been reported in up to 23 % of cases. The neoplastic cells have a ductal phenotype with coexpression of keratins and S100 protein and are surrounded by a layer of myoepithelial cells in non-invasive cases. The main differential diagnosis of LG-SDC includes cystadenoma, cystadenocarcinoma, sclerosing polycystic adenosis, salivary duct carcinoma in situ/high-grade intraductal carcinoma, and papillary-cystic variant of acinic cell carcinoma. There is no published data supporting the continuous classification of LG-SDC as a variant of cystadenocarcinoma. Given that most LG-SDC are non-invasive neoplasms; the terms "cribriform cystadenocarcinoma" and LG-SDC should be replaced by "low-grade intraductal carcinoma" (LG-IDC) of salivary gland or "low-grade intraductal carcinoma with areas of invasive carcinoma" in those cases with evidence of invasive carcinoma.

Sclerosing polycystic adenosis of salivary glands: a review with some emphasis on intraductal epithelial proliferations

Sclerosing polycystic adenosis (SPA) is a rare condition of salivary glands. The most common site is the parotid gland (80 % of cases). SPA shows no gender predilection and occurs over a wide age spectrum (9-84 years). SPA is mostly unifocal, but may rarely be multifocal. Histologically, SPA are sharply circumscribed mostly unencapsulated lesions composed of acinar and ductal components with variable cytomorphological characteristics, including foamy, vacuolated, apocrine, mucous, clear/ballooned, squamous, columnar and oncocyte-like cells. Characteristic for SPA is the presence of large acinar cells with abundant eosinophilic cytoplasmic granules. The stroma is densely collagenized, frequently harbouring a variably intense chronic inflammatory infiltrate and may contain fat. Rarely the stroma is myxoid. Some degree of intraductal epithelial proliferations have been reported in at least 50 % of cases. The proportion of cases with epithelial proliferations that fulfill criteria for high-grade ductal carcinoma in-situ is <10 %. Immunohistochemically, both ductal and acinar cells are positive for broad spectrum cytokeratins. There is variable immunoreactivity for epithelial membrane antigen and S-100 protein. CEA, p53 and HER2 is reportedly negative. Gross cystic disease fluid protein-15 is strongly expressed in the acinar component. There is consistent but variable expression of estrogen and progesterone receptors. The proliferative index (Ki-67) is low (1-2 %) in the benign (acinar and ductal) components. Using HUMARA methodology (non-random inactivation of X-chromosomes), six cases with atypical epithelial proliferations have been shown to be clonal processes. Recurrences have been reported in up to 19 % of cases.

A perspective of comparative salivary and breast pathology. Part I: microstructural aspects, adaptations and cellular events

This is the first part of a review comparing the pathology of salivary and mammary glands. Here, less obvious similarities and differences in functional histology and their influences on pathology are examined with emphasis on myoepithelial cells, stromal components, analogues of mucosa-associated lymphoid tissue, steroid receptors, and intraparenchymal cells of monocytic lineage. Particular cell phenotypes (oncocytic, apocrine, neuroendocrine and clear) are critically evaluated and responses to atrophy, infarction and fine-needle aspiration biopsy procedures are highlighted together with aspects of metaplasia, regeneration, ageing and microcalcification. Areas of controversy or uncertainty which may benefit from further investigations are also discussed.

A unique case of sclerosing polycystic adenosis of the sinonasal tract

Sclerosing polycystic adenosis is an extremely uncommon, recently described, sclerosing lesion of the salivary glands that appears histologically similar to fibrocystic changes of the breast. The key histopathologic features of sclerosing polycystic adenosis include lobular proliferation of ductal and acinar elements, cystically dilated ducts exhibiting frequent apocrine and sebaceous metaplasia, eosinophilic intracytoplasmic granules within some acinar-type cells, intraductal epithelial hyperplasia, and dense fibrosis. Most described cases have occurred in the major salivary glands, particularly the parotid gland. Although most authorities consider sclerosing polycystic adenosis to be a pseudoneoplastic process, the occurrence of dysplasia and carcinoma in situ of ductal epithelium reported recurrence rates of up to 30%, and recent evidence of clonality suggests a possible neoplastic etiology. However, there have been no cases of metastasis. Herein, we report the first case of sclerosing polycystic adenosis of the sinonasal tract in a 79-year-old woman presenting with a sinonasal mass.

Sclerosing polycystic adenosis

A 25-year-old female presented with a well-defined, painless mass of 1 year's duration in the right parotid gland. MR imaging revealed a relatively well-circumscribed lesion involving the deep and superficial lobes of the right parotid gland. Histologic examination of the resection resulted in a diagnosis of sclerosing polycystic adenosis, a rare benign salivary gland entity of presumed non-neoplastic origin. The clinical, radiographic, and morphologic features of sclerosing polycystic adenosis are discussed.

[Sclerosing polycystic adenosis of the submandibular gland]

Sclerosing polycystic adenosis (SPA) is a rare, newly-reported lesion of the salivary glands. Most cases occurred within mayor salivary glands and were frequently confused with other salivary gland carcinomas such as acinar cell carcinoma. We report a case of SPA within the submandibular gland in a 63-year-old woman.

Sclerosing polycystic adenosis of the nasal septum: the risk of misdiagnosis

Sclerosing polycyctic adenosis (SPA) is a rare lesion of unknown etiology morphologically resembling fibrocystic changes of the breast. To date, approximately 41 cases of SPA have been reported. Most cases of SPA have originated in the parotid and submandibular glands, with a few cases of intra-oral minor salivary gland origin. This is the first reported case of sclerosing polycystic adenosis of nasal minor salivary gland origin. The differential diagnosis of SPA includes polycystic disease, sclerosing sialadenitis, and benign and malignant glandular neoplasias. Although atypia ranging from mild dysplasia to carcinoma in situ can occur in some cases, SPA has a favorable outcome. It is important to be familiar with SPA to avoid aggresive treatment that results from a misdiagnosis. We present a case of a 49-year-old man who had 1-year history of right nasal obstruction.