Sclerosing polycystic adenosis of the salivary gland: a report of 16 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.

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.

Clinicopathological profile of sclerosing polycystic adenoma/adenosis: A systematic review

In this systematic review, we aimed to evaluate the clinicopathological profile of sclerosing polycystic adenoma (SPA). PubMed, Scopus, EMBASE, Lilacs, Web of Science, and gray literature were searched to access cases of SPA in salivary glands. One hundred and thirty cases of SPA were found across 61 selected articles. SPA affected mainly the parotid gland of adults with a mean age of 44.6 years old, with a slight preference for females. The lesion was usually presented as a painless firm mass with a long period of evolution. Histologically, they are well-delimitated lesions composed of acinar and ductal elements with a variety of cytomorphologic features surrounded by a densely collagenized stroma. PI3K was the most common gene mutation related to SPA. SPA is a benign condition that mainly affects the parotid gland of female patients and it is usually treated by surgical resection with a good prognosis.

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.

Squamoglandular Variant of Acinic Cell Carcinoma: A Case Report of a Novel Variant

While salivary gland tumors have considerable plasticity, juxtaposition of the morphologies of two named tumor types is rare. Tumors with both mucoepidermoid and serous acinar components, dubbed "mucoacinar" carcinomas were recently characterized, and based on morphologic and molecular features, considered variants of mucoepidermoid carcinoma. Here we describe a unique case of a 59-year-old male with a 0.9 cm right parotid mass with a similar blend of mucoepidermoid-like and acinar elements that instead has a molecular phenotype of acinic cell carcinoma, essentially the reverse of mucoacinar carcinoma. The tumor was fairly well circumscribed with a prominent tumor associated lymphoid response. It consisted of a predominant bland but basaloid squamoid proliferation with scattered pockets of serous acinar differentiation as well as rare mucous cells and tubules. The tumor showed diffuse cytokeratin and DOG1 reactivity as well as p40 expression in the squamoid components. Immunostaining for NR4A3 was diffusely positive, and an NR4A3 rearrangement was noted on fluorescence in situ hybridization, while testing for MAML2 and MSANTD3 rearrangements were negative. Based on these findings, this tumor is best considered a "squamoglandular variant of acinic cell carcinoma." Morphologic and clinical evidence argues against this representing a form of high-grade transformation. While overall bland, the differential diagnosis may include various basaloid tumors in the parotid gland, both primary and metastatic.

Case of labial sclerosing polycystic adenoma with ductal carcinoma in situ (DCIS)

Minor salivary gland tumours are enigmatic in their behaviour and presentations. Histopathological diagnosis of these tumours encompasses a large spectrum. Conventionally, small nodular tumours of the upper lip or the labial mucosa are generally adenomas, frequently pleomorphic adenomas. Here, we describe a case of a solitary nodular tumour, occurring in the upper labial mucosa, diagnosed as sclerosing polycystic adenoma (SPA) with intraductal epithelial proliferation of high grade. This is a rare lesion, which has entered into the category of salivary gland tumours recently in the 2017 WHO categorisation. We report a case of paucicystic SPA with intraductal epithelial proliferations in the labial minor salivary gland of a 56-year-old woman, which might be the first report of a case occurring in the upper labial mucosa.

Mucoacinar Carcinoma: A Rare Variant of Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma (MEC) is generally characterized by an admixture of mucous, epidermoid and intermediate type cells. Numerous variants morphologies are described and defined by stromal and/or cytoplasmic tinctorial characteristics. We now report 11 cases of MEC with serous acinar differentiation, reflecting a distal intercalated duct/acinar phenotype, which we designate as mucoacinar carcinomas. Seven patients were female while 4 were male with a mean age of 55 years (range: 21 to 72 y). Ten cases were from the parotid while 1 was from the submandibular gland. Mean size of the tumors was 1.8 cm (range: 0.7 to 4.5 cm). Three cases were low grade, 7 were intermediate grade, and 1 was high grade. Low to intermediate grade cases demonstrated prominent clear to vacuolated cells with focal serous acinar differentiation. The high-grade case showed a distinctive scattering of acinar cells interspersed between epidermoid cells. Periodic acid Schiff after diastase (9/9), SOX-10 (9/9), and DOG-1 (9/10) highlighted the acinar component. Six of 7 cases showed a focal acinar predominant NR4A3 expression. MAML2 fluorescence in situ hybridization was positive in all cases, in both acinar and mucoepidermoid components. Two cases tested by next generation sequencing showed standard CRTC1-MAML2 fusions. MSANTD3 and NR4A3 fluorescence in situ hybridization on the other hand were negative. Evidence thus suggests that mucoacinar carcinoma represents an acinar variant morphology in MEC, rather than a true MEC-acinic cell carcinoma hybrid, or collision tumor. The acinar differentiation, SOX-10, DOG-1, and even focal NR4A3 reactivity may thus be diagnostic pitfalls.

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 minor salivary glands: Report of a rare case with diagnostic approach and review of literature

Sclerosing polycystic adenosis (SPA) is an uncommon entity occurring in the salivary glands, with majority of the cases reported in major salivary glands reminiscent of fibrocystic disease of the breast. SPA arising in minor salivary glands of the oral cavity constitutes an exceedingly rare phenomenon. Here, we report a case of SPA that presented as a solitary, submucosal mass on the left lower labial mucosa in a 19-year-old male. The pathology features and a clinicopathologic diagnostic approach highlighting key features are discussed here. Similar cases published in the English literature are reviewed.

Coexistence of sclerosing polycystic adenosis and dysgenetic polycystic disease of parotid, Report of a case

Sclerosing polycystic adenosis (SPA) is a rare benign salivary gland lesion. Dysgenetic polycystic disease (DPD), which is a histologically similar lesion, may cause a lattice-like gross appearance with bilateral enlargement of the entire salivary glands. In this report, we present a case of SPA in the right parotid and coexistent DPD involving the both parotid.

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.

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.

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.

Sclerosing polycystic adenosis of the retromolar pad area: a case report

Sclerosing polycystic adenosis is a rare pathological lesion that affects salivary glands. The majority of cases involve the parotid and its occurrence in minor glands is exceedingly rare. Here, we report the first case of this lesion in the retromolar pad area and discuss its histological features and immunohistochemical reactivity with αSMA and Ki67 markers. A review of the literature on its immunohistochemical profile is also provided. Sclerosing polycystic adenosis has a diverse histomorphology and should be differentiated from other more important pathologic lesions.

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.

Fat-containing salivary gland tumors: a review

Fat-containing tumors of the salivary glands are uncommon. Their wide histological spectrum varies from pure lipomatous neoplasms similar to their cutaneous and soft tissue counterparts to mixed lipoepithelial lesions specific to the salivary glands. With few exceptions, these uncommon lesions affect mainly the elderly, with a mean age at presentation of ≥ 50 years and show a predilection for males. A few cases occur in childhood; some of them represent congenital lesions. In decreasing order of frequency, ordinary (soft-tissue type) lipoma, oncocytic lipoadenoma, non-oncocytic sialolipoma, and pleomorphic adenoma/myoepithelioma with extensive lipometaplasia are the main variants of fat containing tumors encountered in the salivary glands. While pleomorphic adenoma/myoepithelioma with lipometaplasia behave in the same way as their non-fat-containing counterparts, other lipomatous salivary gland tumors listed above are cured with simple excision and do not carry a risk of recurrence. Other lipoma variants (spindle cell lipoma, osteolipoma, fibrolipoma, angiolipoma, pleomorphic lipoma, lipoblastoma and hibernoma) are exceptionally rare in the salivary gland. Atypical lipomatous tumors/liposarcoma have been only rarely reported in the salivary gland and they behave in a similar fashion to their soft-tissue counterparts. Diffuse lipomatosis and lobular fatty atrophy are the two tumor-like lesions that might closely mimic sialolipoma, particularly in limited biopsy material without knowledge of the gross findings. This review summarizes the clinicopathological features of the main types of salivary fat-containing lesions and discusses their differential diagnoses.

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.

An analysis of PLAG1 and HMGA2 rearrangements in salivary duct carcinoma and examination of the role of precursor lesions

AIMS

Salivary duct carcinoma (SDC) often arises in pleomorphic adenoma (PA). Putative precursors, including low-grade cribriform cystadenocarcinoma (LGCCC) and ductal carcinoma in-situ (DCIS), are more controversial. Rearrangement of PLAG1 or HMGA2 is seen in 50-70% of PAs, but this has not been investigated in SDC. Using a large collection of SDCs from a single institution, we aimed to study these genes by fluorescence in-situ hybridization (FISH), and to correlate the presence of precursor lesions/intraductal proliferations with gene alterations.

METHODS AND RESULTS

Forty-four SDCs were stained for smooth muscle actin, CK14, and p63, and examined with PLAG1 and HMGA2 FISH. Eight cases were SDC ex-PA; ten had a hyalinized nodule (HN), which is suspicious for PA; six arose in association with LGCCC; and twenty were 'de-novo' SDCs. Ten cases had PLAG1 rearrangement/amplification (22.7%) and eight had HMGA2 (18.2%) rearrangement/amplification. The positive cases were four SDC ex-PAs, eight SDCs with an HN, and five 'de-novo' SDCs. Twenty-three SDC ex-PAs were present in total (52.3%). All six SDC ex-LGCCCs were FISH-negative. Myoepithelial staining surrounded all LGCCCs, and demonstrated DCIS in 17 cases. Eleven DCIS lesions were in SDC ex-PAs or FISH-positive 'de-novo' SDCs. These cases represent 'cancerization' of ducts. Only six FISH-negative 'de-novo' SDCs showed DCIS.

CONCLUSIONS

A large proportion of SDCs arise in PAs (with or without residual evidence of a PA). A small proportion of SDCs arise in LGCCCs. Cases showing DCIS often represent cancerization.

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.

Lymphadenoma of the salivary gland: clinicopathological and immunohistochemical analysis of 33 tumors

Lymphadenomas (LADs) are rare salivary gland tumors. Their clinicopathologic characteristics and etiopathogenesis are poorly understood. We examined 33 LADs in 31 patients (17 women and 14 men) aged 11-79 years (median 65 years). There were 22 sebaceous LADs in 21 patients (9 women and 12 men) and 11 non-sebaceous LADs in 10 patients (8 women and 2 men). Two patients had synchronous double tumors. Twenty-six tumors (79%) arose in parotid, three in the neck, and two each in submandibular gland and oral cavity. Extraparotid tumors were seen in 2 of 21 (10%) patients with sebaceous and 4 of 10 (40%) patients with non-sebaceous LADs. Seven of twenty-three (30%) patients had immunosuppressive therapy for unrelated diseases. The tumors were well circumscribed, encapsulated (n=28, 84%) painless masses, varying in size from 0.6 to 6 cm (median 2.2). The cut surfaces were gray-tan to yellow, homogeneous and multicystic (n=24, 72%). The epithelial cells were basaloid, squamous and glandular, forming solid nests, cords, tubules, and cysts. Sebaceous differentiation was restricted to sebaceous lymphadenoma. The epithelial cells expressed basal cell markers (p63, 34BE12, and/or CK5/6, 18/18, 100%) and the luminal glandular cells expressed CK7 (12/12, 100%). Myoepithelial cells were absent (n=10/16, 63%) or focal. The lymphoid stroma was reactive, with germinal centers in 28 (84%). There was no evidence of HPV (0/11), EBV (0/7), and HHV-8 (0/8). Malignant transformation to sebaceous and basal cell adenocarcinoma was seen in one patient each. None of the 11 patients with follow-up (1-8 years) recurred. In summary, sebaceous and non-sebaceous LADs are benign, encapsulated, solid and cystic tumors affecting older adults. Non-sebaceous LADs affect women and extraparotid sites more frequently than sebaceous LADs. Altered immune status may have a role in their etiopathogenesis. Multiple synchronous tumors, origin in buccal mucosa, and malignant transformation may rarely occur.

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 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.