Discussion
Papillary cystadenoma usually occurs in salivary gland tissues such as oral cavity, head and neck, and has a certain risk of malignant transformation. Some reports have shown that this type of tumor can also be distributed in other parts of the digestive tract, such as lip, tongue, nasopharynx, orbit, zygomatic part, larynx, esophagus, gastroesophageal junction, cardia, gastric antrum, transverse colon, rectum, anus and so on. By reviewing the relevant literature, we analyzed the characteristic of gastrointestinal papillary cystadenoma. The clinical and pathological features were summarized.
Papillary cystadenoma occurring in the digestive tract is extremely rare, and can happen in any part of the digestive tract. At present, the pathogenesis is not clear. Some literatures believe that it may be related to congenital ectopic metaplasia of salivary gland[1]. The clinical manifestations are obviously related to the location of the lesions. Among which the cases occurred in the larynx, esophagus, gastroesophageal junction, cardia and other places can be treated for dysphagia, choking feeling, acid regurgitation and other symptoms [2-4]; When the cases occurred in the transverse colon, rectum, anus and other lower digestive tract can be treated for bleeding, abdominal pain, anal foreign body sensation and other symptoms [5-8]; Some cases such as the tumor was in the gastric antrum may have no obvious clinical symptoms[9]. Endoscopic presentation of the disease are submucosal protuberant lesions or polypoid protuberant lesions. Endoscopic ultrasonography may showed hypoechoic lesions confined to the mucosa or submucosa, with diameters ranging from 1 to 2 cm. Clinically, it needs to be differentiated from gastrointestinal stromal tumor, leiomyoma, neuroendocrine tumor, cyst, lipoma, heterotopic pancreas and other diseases [10].
The pathological features were [11-13]: the tumor was round in shape, with the largest diameter of 1-3cm, nodular on the surface and clear boundary with surrounding tissues. The section is white or grayish white, solid or with different sizes of cysts. There are mucoid substances in the cysts, and small papillae can be seen in the larger cysts. Microscopic examination showed that the tumor was composed of mucous cells and cuboidal cells. The two kinds of cells are staggered. The mucus cells were columnar or cuboidal, with round nucleus, located at one end of the cells. They were small in size, stained deeply, and stained lightly in cytoplasm. The cytoplasm of cuboidal cells is eosinophilic, the boundary is not clear, the nucleus is round or oval, the volume is large, and the staining is light. In papillary cystadenoma, the glandular cavity is extremely enlarged into a cystic cavity, which is lined by columnar or cuboidal glandular epithelial cells, and many proliferating papillae protrude into the cavity. The epithelial cells of the nipple are high columnar, with secretion. There are connective tissue fiber bundles in the center of the nipple, without lymphoid tissue. There are eosinophils in the capsule.
Currently, the understanding of the nature of papillary cystadenoma is not consistent. Most researchers consider it to be benign tumor but locally invasive. Some cases showed severe atypical hyperplasia, or highly differentiated papillary carcinoma and papillary cystadenocarcinoma due to abundant papillary proliferation of ducts. Or abominable mucoepidermoid carcinoma [14-17]. Therefore, the disease has a certain risk of malignant transformation, which should be paid attention to by clinicians.
At present, papillary cystadenoma should be treated with surgery. Endoscopic submucosal dissection and endoscopic submucosal mass removal (ESD, ESE) is recommended for papillary cystadenomas of the digestive tract. Patients were sent to regular endoscopic follow-up after diagnosis by pathology and immunohistochemistry after surgery. The were no complications or recurrence case reported after the endoscopic resection or surgical resection in benign cases.
Therefore, based on this case and a review of the relevant literature, we concluded that papillary cystadenoma can occur in any part of the digestive tract and lacks specific clinical and endoscopic manifestations. And the diagnosis of papillary cystadenoma should be confirmed by pathological examination after complete resection of the lesion by endoscopic surgery or surgical resection. Although the incidence of papillary cystadenoma of the digestive tract is extremely low, it has a certain risk of malignant transformation, so it needs to be paid more attentions to by endoscopologists and pathologists.