Sebaceous Lymphadenoma of Parotid: Case Report of a Rare Entity

Abstract

Sebaceous differentiation can be normally seen in salivary glands. An entity first described by Hamperi. Sebaceous components are present in several salivary gland tumors like Warthin's tumor and mucoepidermoid tumor. But, if the sebaceous component predominates, it is known as a sebaceous adenoma. If lymphatic stroma in the background is prominent, it qualifies as sebaceous lymphadenoma. The term was coined and properly described by McGavran et al., differentiating it from similar appearing tumors like Warthin's tumor, sebaceous adenoma, and mucoepidermoid tumor. Clinicians, as well as pathologists, need to be aware of this entity as it is known to undergo malignant degeneration. Since it is a benign entity, the most common symptom is painless parotid swelling. The patient in this case also presented with painless parotid swelling and underwent preoperative FNAC and MRI. But, the diagnosis was made after surgical excision. The patient recovered well after surgery and is being followed. Since this disease is known for malignant degeneration and recurrence careful diagnosis is required. Histopathological picture may be confused with other common entities like Warthin also known as papillary cystadenoma lymphomatosum since both have sebaceous and lymphoid components. McGavran differentiated between both entities. Sebaceous lymphadenoma can convert to sebaceous adenocarcinoma and is thus important to know the correct diagnosis, even if it is postoperative since recurrence may be associated with malignant changes. Sometimes, the picture may be confused with lymphoma and in that case, immunotyping can come as a rescue for diagnosis. The authors of this report intend to report this rare entity and emphasize the need for clinicians and pathologists being aware of it and keeping it as a differential while dealing with a similar parotid tumor.

Keywords: Parotid tumor; Salivary gland tumor; Sebaceous adenoma; Sebaceous lymphadenoma.

Fig. 1

Clinical picture of patient preoperatively

Fig. 2

a Axial T1-weighted image of the tumor showing hyperintensity compared to surrounding muscles. b Coronal T1-weighted image of the tumor.

Fig. 3

Gross specimen of superficial parotidectomy showing yellowish-brown tumor

Fig. 4

a Low power magnification: islands of sebaceous cells in the reactive lymphoid stroma. b High magnification view: sebaceous cells with no atypia and lymphoid stroma