Indian Journal of Pathology and Microbiology

LETTER TO EDITOR
Year
: 2021  |  Volume : 64  |  Issue : 1  |  Page : 212--213

Oncocytic lipoadenoma of submandibular gland: A rare entity


Lubna Rafiqi, Sangita Keskar 
 Department of Laboratory Medicine, Chinmaya Mission Hospital, Bengaluru, Karnataka, India

Correspondence Address:
Lubna Rafiqi
Chinmaya Mission Hospital, Indiranagar, Bengaluru - 560 038 Karnataka
India




How to cite this article:
Rafiqi L, Keskar S. Oncocytic lipoadenoma of submandibular gland: A rare entity.Indian J Pathol Microbiol 2021;64:212-213


How to cite this URL:
Rafiqi L, Keskar S. Oncocytic lipoadenoma of submandibular gland: A rare entity. Indian J Pathol Microbiol [serial online] 2021 [cited 2021 Feb 26 ];64:212-213
Available from: https://www.ijpmonline.org/text.asp?2021/64/1/212/306521


Full Text



Dear Editor,

Fat-containing tumors of the salivary glands are uncommon. Their histomorphological spectrum varies greatly and ranges from minor scattered adipocytic elements within otherwise typical epithelial or mixed salivary gland tumors to predominantly lipogenic mixed tumors and pure lipomatous mesenchymal lesions.[1] Oncocytic lipoadenoma is an exceedingly uncommon neoplasm of the salivary gland, composed of oncocytic epithelium and adipose tissue. Majority of reported cases of oncocytic lipoadenomas have originated in the parotid gland, with only few reports of submandibular gland involvement.[2] We report a case of oncocytic lipoadenoma involving the submandibular gland.

A 62-year-old female with a history of diabetes mellitus presented with complaints of swelling in the left side of the neck for one year, which had gradually increased in size. She also complained of pain on turning the neck. On examination, a 5 × 4 cm solitary, soft, nontender swelling was found in the left submandibular region. Clinically, a submandibular gland abscess was suspected. Left submandibular gland excision was done.

Gross examination revealed a nodular tissue with identifiable salivary gland tissue, measuring 5.8 × 4.0 × 1.5 cm, in toto. Cut section of nodular part revealed a fatty lesion measuring 3.0 × 2.5 × 1.5 cm with interspersed islands of brown solid areas [Figure 1]. Microscopy revealed normal salivary gland tissue along with a lesion exhibiting thin capsule [Figure 2]. The lesion was composed of mature adipose tissue and interspersed nodules composed of oncocytes. Areas with the proliferation of ducts and few lymphoid aggregates were noted [Figure 3] and [Figure 4].{Figure 1}{Figure 2}{Figure 3}{Figure 4}

First described in 1998, oncocytic lipoadenoma is a histologically distinctive tumor composed of oncocytic cells and mature adipocytes.[3] Oncocytic lipoadenoma is an extremely rare benign tumor of the salivary glands. This entity belongs to a family of fat-containing tumors of the salivary glands including lipoma, nononcocytic sialolipoma, and pleomorphic adenoma/myoepithelioma with extensive lipo-metaplasia.[1]

To date, twenty cases have been reported in the literature.[2],[4] Most of the reported cases are of parotid gland involvement.

Based on the present data, oncocytic lipoadenoma appears to be a benign tumor with no risk of recurrence or aggressive behavior.[3] On gross examination, oncocytic lipoadenomas are well-circumscribed neoplasms. The cut surface may vary from tan to brown to yellow, depending on the amount of adipose tissue present.

Histologically, tumor shows a thin fibrous capsule and has a distinctive appearance characterized by the presence of two cell populations: oncocytes and adipocytes.[2] Oncocytes either show close intermingling with the fatty cells or they may form discrete circumscribed oncocytic nodules within a lipoma-like background.[1] In our case, the oncocytes were seen in discrete nodules in lipoma-like background which could also be appreciated on gross examination [Figures 1 and 2].

Cytogenetic studies on oncocytic lipoadenoma of parotid gland have shown similar molecular alterations as soft tissue lipomas and pleomorphic adenoma (rearrangements of 12q13-15), suggesting that the fatty component is neoplastic and that the two variants of salivary tumors might be closely related, genetically.[2],[5]

We are reporting this case as this entity can pose problems in diagnosis due to its rarity and hence should be kept in differential diagnosis for soft salivary gland space-occupying lesions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Agaimy A. Fat-containing salivary gland tumors: A review. Head Neck Pathol 2013;7:90-6.
2Sean K. Lau, Lester D. R. Thompson. Oncocytic lipoadenoma of salivary gland: A clinicopathologic analysis of 7 cases and review of literature. Head Neck Pathol 2015;9:39-46.
3Hirokawa M, Shimizu M, Manabe T, Ito J, Ogawa S. Oncocytic lipoadenoma of the submandibular gland. Hum Pathol 1998;29:410-2.
4Agaimy A, Ihrler S, Markl B, Lell M, Zenk J, Hartmann A, et al. Lipomatous salivary gland tumors: A series of 31 cases spanning their morphologic spectrum with emphasis on sialolipoma and oncocytic lipoadenoma. Am J Surg Pathol 2013;37:128-37.
5Ilie M, Hofman V, Pedeutour F, Attias R, Santini J, Hofman P. Oncocytic lipoadenoma of the parotid gland: Immunohistochemical and cytogenetic analysis. Pathol Res Pract 2010;206:66-72.