Tag: salivary

Sebaceous Adenoma

This is sebaceous adenoma (SA) of the salivary gland. SA are rare benign tumors usually occurring in the skin but also occasionally reported in salivary gland sites.  Salivary SA more commonly involves major salivary glands (particularly the parotid gland), as seen in this case, but can also arise in the oral cavity, either from minor glands or surface mucosa.

Histologically, SA is comprised of closely packed salivary ducts with marked sebaceous and squamous differentiation with nested and cystic growth. There is no evidence of peripheral tissue, perineural or angiolymphatic invasion. High-grade cytomorphologic features, including increased and/or atypical mitotic figures or necrosis, are not present. SA lacks the lymphoid stroma seen in sebaceous lymphadenoma. Salivary SA does not appear to be associated with cutaneous/adnexal SA and there is no known link to Muir-Torre syndrome.

SA of the salivary gland does not recur after complete excision.

Reference

1. Skalova A, Hyrcza MD, Mehrotra R, et al. Sebaceous adenoma. In: WHO Classification of Tumours Editorial Board. Head and neck tumours [Internet; beta version ahead of print]. Lyon (France): International Agency for Research on Cancer; 2022 [cited 2024 Jan 1]. (WHO classification of tumours series, 5th ed.; vol. 9). Available from: https://tumourclassification.iarc.who.int/chapters/52/355

Quiz Answers

Q1 = False

Q2 = False

Chronic sialadenitis

Chronic sialadenitis typically presents as pain and swelling related to mealtimes. Histologic features include varying degrees of lymphoplasmacytic inflammation with lymphoid aggregate formation, interlobular fibrosis, acinar atrophy, and ductal dilation. The lymphocytic cells are composed of a mixture of B and T cells.

There are many causes of chronic sialadenitis, but the  most common is persistent or recurrent duct obstruction by calculi. Stricture or extrinsic compression by tumor can also impede salivary flow and result in similar changes. Sialadenitis may occur in patients treated by radiation therapy for head and neck cancers, with serous acini of the parotid being more sensitive than the mucous-cell-rich submandibular gland.

Systemic disorders (such as autoimmune conditions or Sjogren disease) histologically present with chronic inflammation, fibrosis, loss of acinar tissue, and characteristic ‘lymphoepithelial lesions’ (proliferations of ductal remnants which are infiltrated by lymphocytes). Clinically, there will be keratoconjunctivitis and/or xerostomia and the swelling is commonly bilateral. Correlation with serological findings of Ro(SS-A) and/or La(SS-B) autoantibodies, rheumatoid factor, and antinuclear antibody would also corroborate the diagnosis.

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that can affect the salivary glands. Distinctively, IgG4-related sialadenitis exhibits storiform fibrosis, obliterative phlebitis, and dense lymphoplasmacytic infiltrates with larger germinal center formation. In addition, it is characterized by markedly increased numbers of IgG4-positive plasma cells, compared to chronic sialadenitis or Sjogren syndrome. Typically, the ratio of IgG4:IgG positive plasma cells is >40% and serologic studies show IgG4 levels of >135 mg/dl in diagnostic cases.

Extranodal marginal zone B cell lymphoma may also be a diagnostic consideration. A lymphoproliferative disorder is suspected by a loss of lobular architecture with extension of atypical monoclonal B-lymphocytes beyond the capsule and into the adjacent tissues.  The neoplastic cells are small to medium in size with relatively abundant pale cytoplasm that imparts a monocytoid appearance.  These cells are CD19+, CD20+, CD79a+, CD3-, CD5-, CD10-, CD23-, and cyclin D1- and demonstrate light chain restriction. Further ancillary testing, such as cytogenetics and molecular studies, may also be used to evaluate for associated chromosomal translocations and/or genetic mutations.

It should be noted that fine needle aspiration is not useful in the diagnosis of chronic sialadenitis due to non-specific findings of the aspirate, which also tends to be paucicellular. In the present case, the patient did not have autoimmune disorders, radiation therapy, or sialolithiasis. The most significant finding was that of marked encasement of the carotid artery and nearby muscular branches supplying the submandibular gland by the squamous cell carcinoma. Given the unilateral presentation of the mass lesion, we include ischemia as a cause of chronic sialadenitis.

In conclusion, the constellation of lymphoplasmacytic inflammation, fibrosis, and acinar loss with sialoliths supports the diagnosis of chronic sialadenitis. Several other causes of chronic sialadenitis have been suggested, including ischemia, as presented in this case.

References

1. Geyer JT, Ferry JA, Harris NL, et al. Chronic sclerosing sialadenitis (Küttner tumor) is an IgG4-associated disease. Am J Surg Pathol. 2010;34(2):202-210. doi:10.1097/PAS.0b013e3181c811ad
2. Xu WL, Ling YC, Wang ZK, Deng F. Diagnostic performance of serum IgG4 level for IgG4-related disease: a meta-analysis. Sci Rep. 2016;6:32035. Published 2016 Aug 25. doi:10.1038/srep32035
3. Geyer JT, Deshpande V. IgG4-associated sialadenitis. Curr Opin Rheumatol. 2011 Jan;23(1):95-101. doi: 10.1097/BOR.0b013e3283413011. PMID: 21124091.
4. Umehara H, Okazaki K, Masaki Y, Kawano M, Yamamoto M, Saeki T, Matsui S, Yoshino T, Nakamura S, Kawa S, Hamano H, Kamisawa T, Shimosegawa T, Shimatsu A, Nakamura S, Ito T, Notohara K, Sumida T, Tanaka Y, Mimori T, Chiba T, Mishima M, Hibi T, Tsubouchi H, Inui K, Ohara H. Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011. Mod Rheumatol. 2012 Feb;22(1):21-30. doi: 10.1007/s10165-011-0571-z. Epub 2012 Jan 5. PMID: 22218969.
5. Neville B, Damm D Allen C and Chi A. Oral and Maxillofacial Pathology ed.4. Elsevier, 2016.
6. Swerdlow  SH, Campo E, Harris  NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds): WHO Calssification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4^th edition).IARC:  Lyon 2017.

Quiz Answers

Q1 = D. Chronic sialadenitis

Q2 = C. It can result from compression by an adjacent tumor.

Sclerosing polycystic adenoma / Sclerosing polycystic adenosis

Sclerosing polycystic adenoma/sclerosing polycystic adenosis is a rare benign lesion of salivary glands. It occurs over a wide age range from children to elderly with a male to female ratio of approximately 2:3. The most commonly involved salivary gland is parotid, followed by the submandibular gland. Most patients present with a singular, painless, slowly enlarging neck mass as an isolated condition without apparent association with other lesions.

These lesions are often well-circumscribed with an absent or incomplete pseudocapsule and are surrounded by normal salivary gland tissue. The cut surface is typically solid with scattered tiny cystic spaces. Histologically, sclerosing polycystic adenoma/adenosis consists of a proliferation of cystic ductal structures and acinar cells surrounded by abundant hyalinized stromal collagen, exhibiting a characteristic lobular architecture. The acinar cells often contain abundant brightly eosinophilic cytoplasmic zymogen-like granules, a key histologic feature of this tumor type. Intraductal epithelial dysplastic proliferations may be seen, ranging from mild to severe dysplasia.

These lesions were initially considered to be a reactive or inflammatory process, and the term “sclerosing polycystic adenosis” was used. However, emerging evidence suggests a clonal process characterized by recurrent gene mutations in the PI3K pathway, with PTEN mutations identified in all analyzed cases. Therefore, the term “sclerosing polycystic adenoma” has been proposed to reflect the likely true neoplastic nature of this process.  

Management of sclerosing polycystic adenoma is conservative surgical excision. Tumor recurrence is uncommon but remains significant. 

References

• Smith BC, Ellis GL, Slater LJ, Foss RD. Sclerosing polycystic adenosis of major salivary glands. A clinicopathologic analysis of nine cases. Am J Surg Pathol. 1996;20(2):161-170.
• Gnepp DR, Wang LJ, Brandwein-Gensler M, Slootweg P, Gill M, Hille J. Sclerosing polycystic adenosis of the salivary gland: a report of 16 cases. Am J Surg Pathol. 2006;30(2):154-164.
• Skalova A, Gnepp DR, Simpson RH, et al. Clonal nature of sclerosing polycystic adenosis of salivary glands demonstrated by using the polymorphism of the human androgen receptor (HUMARA) locus as a marker. Am J Surg Pathol. 2006;30(8):939-944.
• Bishop JA, Gagan J, Baumhoer D, et al. Sclerosing Polycystic “Adenosis” of Salivary Glands: A Neoplasm Characterized by PI3K Pathway Alterations More Correctly Named Sclerosing Polycystic Adenoma. Head Neck Pathol. 2020;14(3):630-636.

Quiz Answers

Q1 = D. PTEN

Q2 = A. True