Slow Growing Carcinomas of Lungs.

 Slow growing carcinoma of lungs

 PKGhatak, MD

Carcinoma is a cancerous growth of the cell that lines the inside of the glands and ducts of glands, it also includes surface cells (epithelial cells) of internal organs like the liver and intestine. The cancerous growth of the connective tissues is called sarcoma and cancers of blood cells are known as Leukemia.

Slow growing carcinomas and potentially malignant carcinomas of lungs were previously grouped under Bronchial Adenoma. Now they are in a separate group.

List of slow growing carcinomas and tumors benign in appearance with a tendency of recurrence and distant metastases.

1. Carcinoid tumors.

2. Adenocystic carcinoma.

3. Mucoepidermoid carcinoma.

Carcinoids.

Carcinoids of the lungs are the major lung tumor of this group, accounts for 85 % of all cancers of the lungs when Small Cell Cancer (SCC) and Non-Small Cell Cancers (NSCC) of the lungs are not included.

Carcinoid tumors also grow in all parts of the gastrointestinal tract, pancreas, ovaries, testis, appendix, thymus gland, and Meckel's diverticulum. Carcinoid tumors develop from Kulchitsky's cells, otherwise called neuroendocrine cells. These cells closely resemble nerve cells but secrete a wide variety of hormones and polypeptides which produce many symptoms due to excess hormone like actions.

This discussion on the endocrine effects of carcinoids will be limited to bronchial carcinoids. 

Symptoms of bronchial carcinoids.

Centrally located tumors are located in the trachea and in equal frequency in the right and left main bronchi. Peripheral carcinoids are much less frequent, and patients are mostly asymptomatic; often detected on chest CT or plain X-ray, an incidental finding. Peripheral carcinoids also cause pneumonia. Because of delayed diagnosis, many peripheral carcinoids are cancerous at the time of biopsy.

The centrally located carcinoid usually is a single lesion. They produce hemoptysis, cough, and episodic wheezing. Under the bronchoscope, the carcinoid tumor appears as a small cherry red, very vascular mucosal tumor. Both sexes are equally affected, usually in people over 50 yrs. of age but all age groups are known to have carcinoids.

The tumor cells are small polyhedral cells arranged in sheets, ribbons, and alveolar or glandular architecture. The nucleus of cells is mostly regular but irregular nuclei and mitotic activities indicate malignancy.

The blood circulation of bronchi is systemic, secretion from carcinoid drains directly into the bronchial veins and bypasses the liver. As a result, even a small amount of hormones/ hormone like substances produced generate significant and persistent symptoms. Carcinoid tumors secrete mostly serotonin and to a lesser amount of histamine, kallikrein, prostaglandins, tachykinins, and various amounts of 40 other chemicals. 

Midgut carcinoids produce a large amount of GI secretory and motility polypeptides.

About 10 % of bronchial carcinoids produce carcinoid syndrome.

Carcinoid syndrome and carcinoid crisis.

Serotonin is 5 hydroxytryptophan (5TP).5TP is produced from an amino acid - tryptophan. Platelets sore serotonin.

Bronchial carcinoids produce intense flushing of the face, neck and upper torsos and become red and itchy. Watery eyes and runny nose develop. Salivation is increased. Wheezing, watery diarrhea, and marked hypotension develop. Carcinoid syndromes are periodic and unpredictable, they may last 2 mins to several minutes and are usually prolonged in bronchial carcinoids.

Carcinoid Crisis.

Symptoms of carcinoid crisis are basically the same but more severe and sustained. Usually, it leads to cardiovascular collapse and cardiac arrhythmias, and death.

Carcinoid crises are precipitated by general anesthesia, tumor manipulation, biopsy, and surgery.

Pellagra.

Niacin is also called vitamin B3, It is also derived from tryptophan. In carcinoids, most of the tryptophan is shunted away for serotonin production. Vitamin B3 deficiency leads to pellagra. The symptoms are known by 3Ds - dementia, dermatitis, and diarrhea.

Increased Fibrosis.

Thickening of the right sided heart valves, intraventricular septum leads to congestive heart failure. Retroperitoneal fibrosis, urethral obstruction, Pyronine's syndrome may develop.

Other Endocrine Manifestations of bronchial carcinoids.

Neurosecretory products of carcinoids are varied - some are Pituitary hormones like GI secretory and motility polypeptides.

Type I Kulchitsky's carcinoid cells produce mostly bronchial obstructive symptoms.

Type II Kulchitsky's cells produce serotonin and other vasoactive and secretory polypeptides. And responsible for Serotonin syndrome and serotonin crisis.

Type III Kulchitsky's cell carcinoids are large cell carcinoma of the lung and Type IV cells are small carcinoma of the lung (SCC).   Type III and IV cell tumors secrete hormones and hormone like products.

The effects of these hormones produce the following syndrome/ entities.

1. Cushing's syndrome from excess ACTH.

2. Hyperpigmentation from melanocytes stimulating hormone.

3. Acromegaly and gigantism from excess growth hormone.

4. Hypoglycemia from insulin like products.

5. Hyperglycemia, hypertension, osteoporosis, renal stones and various other conditions.

 Metastases.

Bronchial carcinoid metastasizes to hilar lymph nodes, bones, and occasionally to distant places via blood.

Adeno Cystic Carcinoma.

Adeno cystic carcinoma is also known as Cylindroma. The tumor arises from the mucus glands of the trachea and main bronchi. The tumor is invasive in nature, spread along the airway underneath the surface layer cells and invades the hilum. and blood vessels. The tumor cells are small pleomorphic, the cells are arranged like tubes. The surrounding stroma shows myxomatous changes. The symptom is hemoptysis. Other symptoms are wheezing and partial bronchial obstruction.

Mucoepidermoid carcinoma.

Mucoepidermoid carcinomas are rare carcinomas and arise from the mucus glands of the trachea and major bronchi. The tumor is a mixture of several cellular types - well differentiated mucus cells, sheets of squamous cells with varying degrees of keratinization, and cellular bridges. Tumors are well circumscribed but noncapsulated and usually project into the lumen of the trachea or bronchi.

Symptoms. Hemoptysis, cough, fever, chest pain.

The tumor is a slow growing and does not invade local issues. Mitotic figures are few.

Diagnosis and treatment of slow growing carcinoma.

Bronchoscopy and biopsy give the proper diagnosis. The choice of treatment is surgical. Various techniques of surgery and the amount of tissues removed depend on the extent of lesions and degree of malignancy. The prognosis is generally good.

For diagnosis and treatment of bronchial carcinoid -please see a previous blog.

https://humihealth.blogspot.com/2011/06/carcinoid-and-other-neuroendocrine.html

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Benign Tumors of Lungs.

Benign tumors of lungs

The Lung cancer surveillance program using a low dose CT scan has resulted in an increase in the detection of lung nodules/ masses. One in every 100 CT scans detects a benign lesion, only a fraction of these nodules are true benign tumors, and the majority are due to infectious granulomas. The plain chest x-ray detects one benign nodule out of 500 chest x-rays.

The previous generation of clinicians included low grade malignant tumors and also benign looking tumors with the tendency of local recurrence and distant metastasis, under the Bronchial Adenomas. Now the malignant and potentially malignant tumors are excluded from the adenoma of the lungs and naturally, the incidence of adenoma has changed.

Benign tumors of the lungs are diverse. All of these tumors, however, have a common mode of presentation, symptoms, methods of diagnosis and options for treatment modalities.

Tumors originating in other structures of the chest are excluded in this discussion.

Mode of presentation.

Incidental.  Patients are symptoms free at the time of detection of a tumor on a CT scan or plain chest x-ray. These tumors are located peripherally.

Symptomatic.  Patients' symptoms are of two categories.

Symptoms of airway obstruction. Patients complain of wheezing, hemoptysis, shortness of breath. These tumors are centrally located in the major bronchi and trachea.

Symptoms of alveoli damage. Repeated pneumonia in the location, lung abscess, chest pain. The tumors are peripherally located.

Work up.

Bronchoscopy and biopsy of lesions are all that are required to make a final diagnosis.

Treatment options.

Tumors are slow growing and often the patients are asymptomatic - waiting with follow up is generally advised.

Surgery.  Most patients are better off having the tumor removed by a limited surgery by video assisted thoracoscopic surgery.

Other modes of tumor ablations are rarely advised.

Classification and some aspects of Benign Tumors of Lungs.

Hamartomas.

Hematomas are the most common benign tumor of the lung. Hamartoma originates from the retained totipotent fetal cells in the lung. The pathological pictures are of a mixed cellular type. Normal lung tissues are mixed with growths from cartilage, fat cells, muscles and mucus glands.

10 % of patients complain of obstructive symptoms. X-ray shows a single mass with a very clear defined border. Occasionally seen as a lobulated nodule of 3cm size A popcorn calcification is a very distinct feature, but diffuse, stippled, or macular calcification may be present. The average age of patients is 40 -60 yrs; the male-female ratio is 2:1.

Bronchial Adenoma.

These benign tumors originate from the lining epithelial cells of the mucus glands of the bronchus. The tumor usually projects into the lumen of the airways. Symptoms are from airway obstruction. The pathological picture consists of mucus filled small acini lined with columnar cells.

Hemangiomas.

This is usually a single lung lesion, when lung hemangioma is a part of hemangioma of the face, the tumor behaves differently and is discussed in an earlier blog. Most patients are symptom free, when they have symptoms, they are from infection and hemoptysis. Histologically there are sheets of rounded endothelial cells lining blood filled spaces, occasional papillary cellular pattern is present.

Leiomyomas.

Leiomyomas arise from smooth muscle cells of the bronchi. All age groups of patients are involved. Female patients are specially prone to leiomyoma. The microscopic picture is bundles of spindle cells with elongated pale nuclei. Rare calcification is seen.

Lipomas.

Lipomas are seen in the major airways, as polypoidal mass projecting into the lumen usually has a morrow base but some lipomas take an hourglass appearance due to intrabronchial and extra bronchial parts. Lipomas originated from the fat cells of the bronchus or from fat cells of the connective tissue situated in between the cartilage rings. The male-female ratio is 5 :1, and the onset of symptoms is at 50 yrs. or older age. The histological picture is a fat cell mixed with some muscle cells and glands.

Lymphangiomyelomatosis.

 The origin of this tumor is the smooth muscle of lymphatics. The tumor may extend to the bronchial wall, venules, arterioles and alveolar sacs. The patients are females of childbearing age, present with shortness of breath. At times patients have persistent chylous pleural effusion and hemoptysis. Female reproductive hormones are perhaps responsible. X-ray shows lower lobe infiltrates of linear or fine nodular infiltrates with hyperinflations of the remaining lung. The diffusion capacity of CO (carbon monoxide) is reduced, so also the ventilation-perfusion ratio, and dead space of the lung is increased, and also the total lung capacity.

Pathological picture - hypertrophy of the smooth muscles of the entire lung and obstruction of all smaller airways.

Lymphangiomas. 

These tumors originate from the wall of lymph channels, tumor consists of lymph filled spaces lined by columnar or cuboidal cells and rarely of stratified squamous cells, making an appearance of a honeycomb. An occasional collection of lymphocytes is also present.

Papillomas.

The tumors are present in the larynx, trachea and main bronchus. Human papillomavirus infection may be responsible. Mixed cell papillary growths are a common pathological picture. In rare instances carcinoma in situ is present. Hoarseness of voice and cough are presenting symptoms.

Neurofibromas.

These benign tumors originate in nerve tissues of the lung, and lesions are round, oval, or lobulated. They are located outside the bronchus. Tumors compress the airways. Tumors are composed of bundles of elongated nerve fibers with palisading nuclei. The bundles are separated by fine fibers called Antoni A tissue.

Myoblasts. The tumor cells have fine granular eosinophilic cytoplasm, and cells are ovoid and polygonal. patients are young and both sexes are equally affected.

Chondromas.

These tumors are not to be confused with hamartomas. Tumor originates from the cartilage cells for the rings of major airways.

Pseudotumor. 

This is a radiological finding, not a tumor as such. When fluid accumulates in the horizontal fissure between the right upper and middle lobes of the lung, on PA chest X-ray shows a spindle shaped tumor and on the right lateral view, the mass appears as a triangle. The tumor disappears as fluid dissipates from improved congestive heart failure. For this reason, the tumor is also called a phantom tumor and a vanishing tumor.

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