What Are the Different Types of Primary Adenocarcinoma?

Adenocarcinoma is a malignant tumor of the salivary gland epithelium. It has different structures but does not have the components of pleomorphic adenoma. Adenocarcinoma accounts for 9% of salivary gland epithelial tumors, which is one of the more malignant tumors in salivary glands.

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Adenocarcinoma Introduction

Adenocarcinoma is a type of lung cancer that has the smallest relationship with smoking and accounts for 40% of primary lung tumors. Often located in the periphery of the lung, it also affects the pleura and forms associated scarring and pleural effusion. Peripheral adenocarcinoma has long been theorized in scar areas associated with tuberculosis or infarction or other damage. The concept of scar cancer suggests that changes in the precancerous epithelium in the scar area cause cancer. However, some researchers have suggested that scars are secondary to cancer.

Adenocarcinoma

Adenocarcinoma is a glandular epithelial malignant tumor that can have acinar, nipple, bronchioloalveolar, or solid growth patterns. It is often accompanied by mucus production. Detection of mucus requires special staining, especially in poorly differentiated tumors. Mucus testing can sometimes identify solid adenocarcinomas as well as large cell carcinomas with other morphological manifestations.

It can be divided into three types from the organizational form. Glandular epithelial cancer, mucinous cancer, and simple cancer.

Adenocarcinoma pathophysiology

Adenocarcinoma pathological changes

(I) The gross morphology of the tumor is round or oval, most of which are not enveloped, but incomplete. The texture is medium hardness and the cut surface is off-white.

(2) Microscopic examination of the tumor cells showed significant atypia and varied structures. Some are solid masses or small strands arranged, some visible glandular cavity formation, and some arranged into a tubular or glandular structure. It is generally believed that those with glandular cavity-like structures have a higher degree of differentiation and a lower degree of malignancy. The connective tissue between small strips and small clumps is more or less variable. Many are similar to hard cancers, and those with less interstitial and more cancer cells can be called soft cancers.

(3) Biological characteristics Adenocarcinoma has highly infiltrating and destructive growth characteristics. Adenocarcinoma easily invades the walls of blood vessels and lymphatic vessels, and has more hematogenous and lymphatic metastases.

Adenocarcinoma as seen by naked eyes

Adenocarcinoma is mostly located in the periphery of the lungs, with clear boundaries. Related fibrosis and pleural shrinkage can also be seen. The tumor can pass through the pleura to the chest wall. Whether the tumor penetrates the pleura is important in clinical staging and may require elastic fiber staining to confirm. The tumor was grayish white with bleeding and necrosis. If the tumor produces a certain amount of mucus, a luminous or mucus-like area can be seen on the section. These peripheral tumors are often unrelated to the bronchi, but malignant pleural effusions often occur. For this reason, sputum specimens have significantly less adenocarcinoma than squamous cell carcinoma.

Adenocarcinoma seen under microscope

Common bronchial adenocarcinomas form a glandular cavity structure, and tumors can be composed of well-differentiated and poorly-differentiated components. Intracellular mucus needs to be confirmed by special staining mucus card staining or PAS staining. In addition, papillary or small tubular structures can also be seen, adenocarcinoma can also have unusual structures: clear cells, signet ring cells and spindle cells. Pathological adenocarcinoma must be distinguished from mesothelioma. This is difficult for cytological specimens, and other auxiliary methods are needed to accurately type.

Adenocarcinoma cells are more consistent than squamous cell carcinomas or large cell carcinomas. Larger cells, larger nuclei, higher nuclear-plasma ratio, and obvious eosinophilic nucleoli. Visible vacuoles in the cytoplasm indicate mucus production. Unlike squamous cell carcinoma, the boundaries of the cells are unclear. Histological grades are classified as well differentiated, moderately differentiated, or poorly differentiated, and most are moderately differentiated. Adenocarcinoma is generally diagnosed without immunohistochemistry, but immunohistochemistry is needed to distinguish primary, metastatic, or mesothelioma.

Adenocarcinoma symptoms

The appearance of adenocarcinoma mainly depends on the location of the tumor. Adenocarcinoma often has symptoms such as refractory and irritating cough, blood spots in the sputum or a small amount of blood, tingling in the chest or more sputum in the chest. If the tumor is large, it can be oppressed. Symptoms, ipsilateral diaphragm palsy (compression of the phrenic nerve), shortness of breath in the pleura (invasion of the pleura), edema of the head and face, venous distension (compression of the superior vena cava), numbness of the limbs, no sweat on the face, edema, drooping eyelids (brachial plexus nerve compression ).

I. Distant metastatic manifestations: The most common metastatic sites of adenocarcinoma are the brain, bone, liver, and adrenal glands. Patients with brain metastases may develop symptoms of intracranial hypertension and localization, including headache, vomiting, blurred vision, dizziness, weakness of one limb, ataxia, etc. Patients with bone metastases may experience local pain, fractures, and hypercalcemia. Patients with liver metastases may develop anorexia, pain in the liver area, liver enlargement, jaundice, and ascites. Adrenal metastases may show symptoms such as high blood pressure, or may have no symptoms. In addition, adenocarcinoma can also metastasize to lymph nodes on the surface of the body. The most common is metastatic lymph nodes on the bilateral clavicle. Masses can appear locally, but they are not painful and itchy, and they are often found inadvertently.

2. Stomach cough: over 40 years of age, unexplained, refractory irritant cough, often an early precursor of adenocarcinoma, especially the central type, which is more important because of the spasm contraction of the atmospheric ducts stimulated by cancerous tumors As a result, the aura signals of central lung cancer are disclosed much earlier than those of peripheral lung cancer. Chest pain Chest tingling is also an early signal. It is sharp in nature and mostly appears in undifferentiated lung cancer earlier.

3. Hemoptysis: It is an early signal of central lung cancer. Due to the rich distribution of tracheal mucosal blood vessels, there is a small amount of blood filaments. Peripheral lung cancer is relatively late because of its distance from the trachea. Lung adenocarcinoma may have unexplained low fever, especially intermittent fever (reported to account for 70%), and those who have the above symptoms should be paid attention to. Reported symptoms of irritant cough, changes in cough patterns of primary bronchitis, or persistent refractory cough (ineffective for more than three weeks).

Adenocarcinoma disease treatment

Because adenocarcinoma grows invasively, it should be extensively resected. Adenocarcinoma lymph node metastasis rate is high, which can be as high as 36% to 47%. Radical or selective cervical lymph node dissection should be performed at the same time as the primary tumor is removed. Regarding the treatment of the facial nerve, it is necessary to sacrifice the facial nerve in order to completely remove the tumor regardless of whether the facial nerve is paralyzed. The frozen tissue pathology section should be used during the operation to check whether there are residual tumor cells at the surgical margin.

Adenocarcinoma is not sensitive to radiation and should not be treated with radiation alone, but adjuvant treatment after surgery may also improve the effect. For those who are not suitable for advanced surgery, palliative radiotherapy has a certain control effect, but it cannot achieve the purpose of radical cure. Adjuvant chemotherapy can also be used after surgery.

Adenocarcinoma disease prognosis

Adenocarcinoma has a high lymph node metastasis rate, is prone to relapse, and has a poor prognosis. Lin Guochu reported 68 cases of adenocarcinoma, and the 5-year and 10-year cure rates were 43.9% and 29.0%, respectively.