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

Abstract

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 nonsebaceous LADs in 10 patients (8 women and 2 men). Two patients had synchronous double tumors. Twentysix 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 nonsebaceous LADs. Seven of twenty-three (30%) patients had immunosuppressive therapy for unrelated diseases. The tumors were well circumscribed, encapsulated (n ¼ 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 ¼ 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 ¼ 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 followup (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.

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

“…While non-sebaceous lymphadenomas do have a stronger female predilection, they are overall biologically similar. Only rare cases of malignant transformation are described [28].…”

My Journey into the World of Salivary Gland Sebaceous Neoplasms

“…It also stains the germinative cells of the secretory portion of sebaceous glands [54]. In a recent paper, p63 stained all sebaceous and NSLs, 11 and 7, respectfully [21], while a separate study found that all 16 metastatic renal cell carcinomas were negative for this antibody [55]. In addition, three primary sebaceous carcinomas of the skin in several recent studies also stained with p63 [54,56,57].…”

“…To date, 22 NSLs have been reported [19][20][21][26][27][28]. Patients typically present with a mass that has been present for up to 5 years.…”

“…7). Non-sebaceous lymphadenoma (NSL) is histologically similar, but without sebaceous differentiation [19][20][21]. These tumors do not appear to have any association with Epstein Barr virus, papilloma virus, or HHV-8 [21].…”

“…Less than 100 cases have been reported to date [4,5,[21][22][23][24][25]. Patients typically present with a mass, which may be slowly enlarging.…”