bubble_chart Overview

Adenolymphoma, also known as papillary cystadenoma lymphomatosum or Warthin's tumor, was first reported by Albrecht and Arzt in 1910, who referred to it as papillary cystadenoma lymphomatosum. Warthin described two cases in detail in 1929, hence the name. The origin of adenolymphoma is debated, but most believe it arises from ectopic salivary gland tissue remaining in adjacent lymph nodes. Similar glandular ducts have been observed in lymph nodes within the parotid region of embryos and near typical adenolymphomas. Immunological studies show that the lymphoid tissue in the tumor is mainly composed of T lymphocytes and a few B lymphocytes. Ultrastructural observations suggest that this lymphoid tissue results from cell-mediated immune responses. Therefore, it is believed that the lymphoid components in the tumor tissue originate from normal or reactive lymph node tissue in the parotid region and do not participate in tumor formation and growth.

bubble_chart Pathological Changes

1. Gross morphology: The size of adenolymphoma is generally not large, with a diameter usually ranging from 3 to 4 cm. The tumor surface is smooth, often showing grade I lobulation, with a complete and thin membrane, appearing round or oval, soft, compressible, and sometimes cystic. The cut surface is mostly solid, resembling caseous material, grayish-white, with a uniform texture. Partially cystic, it often contains brown, clear, mucoid, gelatinous, or milky substances flowing out from the cyst.

2. Microscopic examination: The tumor is composed of epithelial and lymphoid tissues. The epithelial components form irregular large glandular ducts or cystic cavities, with papillae protruding into the lumen, containing red-stained amorphous substances. Sometimes, cholesterol crystal clefts or a small number of inflammatory cells are seen. The epithelial cells are arranged in two layers: the inner layer consists of tall columnar cells with granular, eosinophilic cytoplasm; the outer layer cells are cuboidal, polygonal, or round, with vacuolated nuclei, lightly stained, and nucleoli visible. The glandular duct epithelial cells show no atypia. Occasionally, squamous metaplasia of epithelial cells is seen, and rarely, mucous cells, sebaceous gland cells, and ciliated columnar epithelial cells are observed. Epithelial cells can also form solid masses. In addition to some fibrous connective tissue, the stroma contains many lymphocytes densely arranged into masses of varying sizes or forming lymphoid follicles with germinal centers.

3. Biological characteristics: Adenolymphoma grows slowly, and the tumor is generally not large, rarely exceeding 10 cm in diameter. Literature reports a local recurrence rate of 5.5% to 12.2%, but Evans et al. believe that the so-called recurrence is not the growth of the original lesion but rather a multifocal characteristic, with more than one tumor possibly present in the same parotid gland, and bilateral occurrence is also possible. Malignant transformation of the tumor is extremely rare.

bubble_chart Clinical Manifestations

Adenolymphomas most commonly occur in the parotid gland, which is characteristic of adenolymphomas. There are also reports of them occurring in the submandibular gland, but some believe these cases still originate in the part of the parotid gland adjacent to the submandibular gland, possibly related to their tissue origin. Within the parotid gland, the common sites are the posterior surface and the root of the nose. The incidence of adenolymphomas accounts for 6% of salivary gland tumors, 8.4% to 20.7% of major salivary gland tumors, and 17% to 33% of benign parotid gland tumors. Adenolymphomas can occur at any age but are most prevalent between 40 and 70 years old, and are extremely rare in children. They predominantly affect males, accounting for 85% to 90% of cases.

Most patients present with a slowly growing, painless mass as the main complaint. The mass is usually round or oval with a smooth surface. In most cases, the tumor is soft and flexible, with a few being cystic. It has clear boundaries, is movable, and is not adherent to the skin, generally not exceeding 6 cm in size. Clinically, it is difficult to distinguish from other parotid gland tumors. During surgery, the tumor's membrane is found to be thin and fragile, easily peeled off but prone to rupture, releasing yellow or brown fluid. In a few cases, the mass may have a fluctuating sensation or tenderness. There is generally no functional impairment.

bubble_chart Diagnosis

Based on detailed medical history and clinical examination, and by understanding the patterns and characteristics of the disease, preoperative diagnosis is generally not difficult. However, it should be differentiated from other parotid gland tumors, branchial cleft cysts, and lymph node enlargement.

Sialography shows benign space-occupying lesions, with the main duct either curved or unchanged, and the branch ducts exhibiting disordered arrangement, twisting, irregular dilation or narrowing, and relatively regular filling defects in the acini.

Isotope 99mTc scanning is specific for the diagnosis and differential diagnosis of adenolymphoma. Since adenolymphoma is composed of epithelial cells and lymphoid tissue, the highly differentiated epithelial cells form tubular structures, possibly retaining their normal aggregation mechanism. The epithelial cells contain a large number of mitochondria. The tumor can uptake pertechnetate, with levels higher than normal parotid tissue, and the scan shows a "hot" nodule.

bubble_chart Treatment Measures

The only treatment for adenolymphoma is surgical resection. Due to the increasing reports of recurrence, this may be related to its multifocal tumor characteristics. Foote, Patey, Kleinsasser, and Guo Yuanzhu from China have all reported the multifocal nature of adenolymphoma. Therefore, superficial parotidectomy with preservation of the facial nerve or subtotal lobectomy is the best surgical approach. During surgery, lymph nodes within the gland should be removed as much as possible to prevent the development of new lesions in the future.

bubble_chart Prognosis

Surgical resection of adenolymphoma can lead to a cure.