Adenoid cystic carcinoma

Introduction to adenoid cystic carcinoma Adenoid cystic carcinoma (adenoid cystic carcinoma), also known as cylindroma or adeno-carcinoma of cylindromatype, is the most common malignant epithelial tumor of the lacrimal gland, and the most malignant, in the development of lacrimal gland epithelial tumors. The rate is second only to pleomorphic adenoma. Because of its high occultity and strong invasiveness, it is late when it is discovered. At the same time, it is adjacent to the mouth, nose, eyes and skull base. It can cause damage to multiple organs around it, easy to invade along the nerve, and the prognosis is often not good. Modern Continuous improvement of treatment methods has found that comprehensive treatment has good prospects. basic knowledge The proportion of illness: 0.025% Susceptible people: no specific population Mode of infection: non-infectious Complications: facial paralysis

Adenoid cystic carcinoma

(1) Causes of the disease

The cause is still unclear. Most people think that the tumor is from the parotid duct, or it may come from the basal cells of the oral mucosa.

(two) pathogenesis

The occurrence of tumors stems from the malignant transformation of normal cells in the body, changes in biological behavior, and the formation of autonomously growing new organisms, which are related to the changes in intracellular genetic material caused by tumorigenic factors.

Adenoid cystic carcinoma prevention

prevention

The regularity of lifestyle and the early warning of early symptoms of parotid gland disease are important. Early detection, early diagnosis and early treatment can improve the cure rate and survival rate of the disease.

Recurrence and prognosis

ACC is an invasive tumor that spreads gradually and widely around the tumor through submucosal and fibrous tissues. At the same time, it gradually expands along the nerve. Therefore, the local recurrence rate is high, especially those with positive surgical margins. However, the tumor grows slowly, and the patient can coexist with the tumor for a long time. Such tumors are regularly followed up within 1/2 to 1 year after surgery to prevent a large range of tumor recurrence or invasion of the brain, and the chance of further treatment is lost.

Adenoid cystic carcinoma Complications

Adenoid cystic carcinoma grows slowly, but it has no capsule, and it is very invasive. The infiltration range often exceeds the range of tumor seen by the naked eye during surgery. Because of the easy recurrence after surgery, the lymphatic metastasis of the tumor is rare, mostly for hematogenous metastasis. To the lungs, bones, etc., occurred in the parotid gland, one-third of the facial paralysis, eyelid destruction, backward invasion can lead to the apical syndrome.

Adenoid cystic cancer symptoms Common symptoms Parotid swelling, eyebrow bow pain, ptosis, sacral humerus, parotid gland, painless mass, conjunctival edema, corneal ulcer, eyelid pain

Adenoid cystic carcinoma accounts for 5% to 10% of parotid tumors, and accounts for 24% of parotid malignant tumors. It occurs in the parotid gland and is common in the parotid gland. Although the parotid gland is rare, it is the submandibular gland. Tumors with sublingual gland are only 2% to 3% in parotid tumors, Eeroth reports 2513 cases of parotid gland tumors, including 119 cases of adenoid cystic carcinoma, 49 cases of parotid gland, and 2 of parotid tumors %; 26 cases of submandibular gland, accounting for 16% of submandibular gland tumors; 44 cases of parotid parotid gland, accounting for 24% of parotid gland tumors, 225 cases of domestic sputum report, 162 cases occurred in small parotid gland, including crotch Of the 87 cases, 38.7%, 63 cases occurred in the large parotid gland. There was no significant difference in the incidence of men and women, or a little more women, the most common age was 40 to 60 years old.

The early stage of the tumor is more painless mass, the tumor is generally small, mostly in 1 ~ 3cm, but some of the volume is also larger, the shape and characteristics of the tumor can be similar to mixed tumor, round or nodular, smooth, most mass The boundary is not very clear, the activity is poor, some are fixed and have adhesion to the surrounding tissue, the tumor often spreads along the nerve, and the adenoid cystic carcinoma that occurs in the parotid gland has more chance of facial nerve paralysis, and can be involved along the facial nerve expansion. Mastoid and humerus; adenoid cystic carcinoma of the submandibular gland or sublingual gland, which can extend along the lingual or hypoglossal nerve to a location far from the primary tumor, and cause ipsilateral tongue sensation and movement disorders; Adenoid cystic carcinoma can expand along the maxillary nerve to the skull, destroying the skull base and causing severe pain. Tumors often invade adjacent bone tissue, such as those occurring in the submandibular glands and sublingual glands, often involving the mandible; The ankles often involve the humerus, etc., which occurs when the small adenoid cystic carcinoma involves the mucosa. In addition to the hard texture and the small nodular mass on the surface, the obvious, reticularly expanding capillaries are often seen. Patients appear in addition to late Complications worsen the condition and generally have no obvious systemic symptoms.

The clinical manifestations are more acute, mainly manifested as hard and solid masses of the upper iliac crest, irregular growth, protruding and protruding movements of the eyeball, and severe periorbital and conjunctival edema in the early stage of the disease. Spread along blood vessels, nerves and other tissues, early invasion of nerves and adjacent periosteum, bone wall, destruction of bone, so often eye and head pain, localized tenderness, pain often located in the eyebrow and frontal area, pain is adenoid cystic The main symptoms of cancer, the nature of pain is intermittent or persistent, some of the pain is mild, and some can be severe, and unlike other lacrimal gland tumors, the incidence of pain is as high as 79%, spontaneous pain and tenderness exist. When the tumor grows to a certain extent, it affects the eye movement and visual function. The late lesion invades the upper part of the palate and causes the ptosis. Some patients have clinical manifestations similar to benign tumors. Only the signs of malignant tumors are found in the imaging examination, but the clinical manifestations of most patients. Symptoms and signs are easy to consider the possibility of malignant tumors, as well as rare tumor recurrence and spread to the subcutaneous and hernia, benign lacrimal gland tumor surgery The recurrence of malignant tumor combined pain becomes conceivable, some patients no clinical manifestations of particularity, lacrimal gland, and benign tumors generally similar, i.e. a longer history, painless.

Examination of adenoid cystic carcinoma

Histopathological changes: the giant examination showed no intact capsule, the face was gray or accompanied by hemorrhage, small cystic changes, and under light microscope, the columnar basal-like cells constituted five histological images: 1 sieve (Swiss cake), tumor cells Single or double layer arranged in adenoid or mesh shape, the cavity contains basophilic mucus, fibrous spacing to form leaflets; 2 tubular, lined with multi-layer epithelial cell-like structure; 3 solid type, also known as basal-like Type, the tumor cells are closely arranged, in the form of flakes or solids with fibrous tissue spacing; 4 acne type, surrounded by multi-layered tumor cells, with necrotic foci in the center; 5 sclerotic type, which is in the interstitial of dense glassy Compressed cell cords, different images often exist in the same tumor. This tumor often invades nerves and blood vessels. Because most lesions in histology contain basal-like cell nests, there are often hardened basement membrane-like materials surrounding them, which are cylindrical. Therefore, it used to be called a cylindrical tumor or a cylindrical tumor type adenocarcinoma.

1. X-ray examination of the parotid angiography X-ray film no special findings in the early stage, the lacrimal gland enlargement and osteolytic bone destruction can be seen in the late stage.

2. Ultrasonography B-ultrasound shows lacrimal gland area lesions, the shape is flat or fusiform (the shape of the tumor is very important for the diagnosis of lacrimal malignant tumors), the boundary is clear, the internal echo is uneven, the sound attenuation is moderate, and the posterior border of the tumor is irregular. , A super shows that the internal reflection of the lesion is irregular and the attenuation is obvious. Doppler scan can show that the blood supply in the tumor is rich.

3. CT scan of adenoid cystic carcinoma has a special sign, which is characterized by high-density space-occupying lesions in the upper part of the iliac crest. The shape is flat, fusiform or irregular (sometimes similar to thickening of the lateral rectus muscle) The lesion grows along the outer wall of the iliac crest to the tip of the iliac crest, which has obvious enhancement. It can be boneless in the early stage. This growth mode is quite unique, accounting for more than 80% of the cases. Some lesions spread to the intracranial and late stages through the supracondylar fissure. Pathological infiltration of bone causes bone destruction. Some scholars believe that early bone destruction is rare because this cancer often occurs in young people. The young patient's tibia is more likely to cause local expansion rather than bone destruction than adults, and a small number of cases. There may be calcification in the tumor, which is also a feature of lacrimal malignant tumors.

Some people have analyzed the CT and X-ray of 16 cases of lacrimal gland epithelial tumors. It is believed that about 73% of lacrimal gland malignancies can be correctly diagnosed by CT+X line. The indications are: 1 adjacent bone destruction, bone erosion; 2 tumor Internal calcification; 3CT shows that the tumor area is large, spreading to the outside of the lacrimal gland or reaching the tip of the sac, and the more extensive the lesion may be malignant, the irregular lesion and spreading to the apex may also be a malignant tumor.

4. MRI tumors showed low-to-low signal on T1WI, T2WI showed high signal or medium-high signal, and the enhancement was obvious. The tumor was extensive in MRI, invading bone and surrounding structures such as axillary fossa, intracranial, etc., tumor hemorrhage and necrosis The cavity has a medium-high heterogeneity signal on TlWI. Since the bone has no signal on MRI, especially on T1WI, if the tumor is a medium signal, the bone signal is poorly displayed, while the general tumor signal on T2WI is high. BRI with still low signal can be better displayed.

Diagnosis and differentiation of adenoid cystic carcinoma

diagnosis

Adenoid cystic carcinoma is the same as other types of malignant tumors of the parotid gland. Preoperative diagnosis is a difficult problem. Patients with early pain and neurological paralysis of the parotid gland should first consider the diagnosis of adenoid cystic carcinoma. For further diagnosis, it can be done. Fine needle aspiration cytology, microscopically, the tumor cells are round or oval, like basal cells, and aggregate in a globular shape; the mucus is in the shape of a pellet, with one or more layers of tumor cells around it. The unique manifestation is not found in other parotid epithelial tumors. It can be diagnosed as adenoid cystic carcinoma. It is difficult to correctly determine the extent of adenoid cystic carcinoma. The existing examination methods, such as parotid angiography X-ray Tablets, B-mode ultrasound, CT and radionuclide scanning cannot solve this problem.

(1) Gross shape The tumor is round or nodular, varying in size, but the diameter is more than 2 to 4 cm. The boundary with the surrounding tissue is unclear. The mass is mostly substantial, the texture is slightly hard, no capsule, and the cut surface is gray. Or light yellow, moist, partially visible microcapsules, a small number of large sacs.

(B) There are two types of tumor cells, namely, the lining of epithelial cells and myoepithelial cells. The tumor cells are arranged in a variety of ways. The sieve-like structure is a typical image of the tumor. The tumor cells are arranged in a circle and oval. a shape or irregularly shaped epithelial mass containing a plurality of round or oval cystic cavities of varying sizes, in the form of a mesh, similar to the cross-section of the tendon, which are mostly tumors The myocutaneous epithelial cells are surrounded by mucus-like substances. Under electron microscopy, the cavity contains a substrate, a star-shaped granular mucus and collagen fibers. The collagen fibrils can be glass-like and even occupy the entire cyst to form a transparent protein. Cylinder.

In adenoid cystic carcinoma, in addition to the sieve-like structure, it can be seen that the tumor cells are densely arranged with solid small strips, small clumps and small duct-like structures, and small duct-like structures are surrounded by 2 to 3 layers of cells, sometimes The cavity contains red stained mucus, solid adenoid cystic carcinoma is rare, often part of a larger solid mass, part is still a sieve structure or a small strip, the central part of the large mass can occur Degeneration, necrosis and cystic changes.

(3) Biological characteristics Adenoid cystic carcinoma grows slowly, but has no capsule, and is highly invasive. The infiltration range often exceeds the range of tumors seen by the naked eye during surgery. Because of the easy recurrence after surgery, the tumor has a follow-up Or around the tendency of fiber growth, so the tumor can grow around the nerve, invading the nerve coat and nerve fiber bundle, causing neurological symptoms, can also grow along or around the blood vessels, making vasoconstriction dysfunction, causing bleeding during surgery, tumor It can also spread along the blood vessels, nerves, and collagen fibers to the glandular tissue and other tissues. The advanced tumor cells are also easy to invade the blood vessels, and blood transfer occurs. According to Spiro, the distant metastasis rate is 43%, often transferred to the lungs, liver and bone. And lymphatic metastasis is rare.

According to medical history and imaging examination, most tumors can be diagnosed correctly before operation. X-ray plain films can only show the changes of the iliac crest and the iliac crest, which lack specificity for the diagnosis of this disease. It shows that the intracapsular cystic zone is sensitive. Color Doppler can show the blood supply in the tumor, but it is not satisfied with the growth mode and range of the tumor. It is also difficult to show the change of bone. This disease can be used as an auxiliary examination method. CT is The best method for the diagnosis and differential diagnosis of adenoid cystic carcinoma can accurately display the growth mode and range of the tumor, and can clearly show the characteristic bone changes, but it is not sensitive to the internal structure of the tumor. MRI can be used as the disease. The supplementary examination method can clearly show the relationship between the inside of the tumor and the adjacent structure and the extension range, especially the extension to the external iliac crest, but it is difficult to show the cortical bone changes in the sacral wall. The histopathological examination can confirm the diagnosis.

Differential diagnosis

1. Lacrimal glandular pseudotumor is sometimes similar to the clinical table of adenoid cystic carcinoma, such as eyelid swelling, mass outside the iliac crest, pain, and even CT shows that the shape of the lesion may be flat, but the inflammatory pseudotumor often has an eyelid There is redness and recurrence, and it is effective for corticosteroid treatment. In addition, the inflammatory pseudotumor of the lacrimal gland shows that the echo in the lesion is lacking, so the echo in the lesion is uneven or blocky.

2. Other lacrimal gland epithelial tumors are easily distinguished by the shape of the features on the CT image.

3. Lacrimal gland lymphoma is susceptible to lacrimal gland lymphoma, with a long history and no significant pain. Sometimes CT and MRI are similar to lacrimal gland malignancies, but ultrasound often shows lesions with low echo or low reflex.

4. Different from basal cell carcinoma, basal cell adenoma occurs in the parotid gland in the large parotid gland. The upper lip of the parotid gland is most common. It is more common in male patients. It is rare in people younger than 40 years old, with the most incidence from 50 to 60 years old. The tumor grows slowly, has a long course of disease, has no symptoms, and often treats with a painless mass. The tumor has clear boundaries, no adhesion to surrounding tissues, and activities are mostly round or elliptical. The texture is soft, and the parotid gland is X-ray. It is a space-occupying lesion of benign tumors.

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