1. Latent carcinoma. This is found unexpectedly as a small focus of carcinoma in the prostate during autopsy studies in men dying of other causes. Its incidence in autopsies has been variously reported as 25-35%.
2. Incidental carcinoma. About 15-20% of prostatectomies done.
3. Occult carcinoma. This is the type in which the patient has no symptoms of prostatic carcinoma but shows evidence of metastases on clinical examination and investigations.
4. Clinical carcinoma. Clinical prostatic carcinoma is the type detected by rectal examination and other investigations and confirmed by pathologic examination of biopsy of the prostate.
Morphology
Macroscopically, the prostate may be enlarged, normal in size or smaller than normal. In 95% of cases, prostatic carcinoma is located in the peripheral zone, especially in the posterior lobe. The malignant prostate is firm and fibrous. Cut section is homogeneous and contains irregular yellowish areas.
Microscopically, there are 4 histologic types of cancer of the prostate adenocarcinoma, transitional cell carcinoma, squamous cell carcinoma and undifferentiated carcinoma.
Metastases:
Lymphogenous: sacral, iliac and para-aortic lymph nodes.
Hematogenous: pelvis, lumbar spine, lungs, and kidneys, brain.
Liver tumors
Benign tumors
1. Liver cell adenomas are pale, yellow-tan, and frequently bile-stained nodules, found anywhere in the hepatic substance but often beneath the capsule.
They may reach 30 cm in diameter. Although they are usually well demarcated, encapsulation may not be macroscopically evident.
Microscopically, liver cell adenomas are composed of sheets and cords of cells that may resemble normal hepatocytes or have some variation in cell and nuclear size. Portal tracts are absent; instead prominent arterial vessels and draining veins are distributed through the substance of the tumor. A capsule that rahges from delicate collapsed reticulin to well-defined connective tissue usually separates the lesion from the surrounding parenchyma, but it may be deficient in places or entirely absent.
2. Bile duct adenomas are firm, pale, and usually single discrete nodules rarely more than I cm in diameter, frequently found in a subcapsular location, in contrast to the liver cell adenoma, they are almost never bile stained.
Microscopically they are composed of uniformly sized, epithelium-lined channels or ducts separated by a scant-to-abundant connective tissue stroma and sharply demarcated from the surrounding liver.
Malignant tumors
1. Hepatocellular carcinoma may appear macroscopically as a unifocal (usually large) mass; multifocal, widely distributed nodules of variable size; or a diffusely infiltrative cancer, permeating widely and some times involving the entire liver.
All three patterns may cause liver enlargement (2000 to 3000 gm), particularly the unifocal massive and multinodular patterns.
The diffusely infiltrative tumor may blend imperceptibly into a cirrhotic liver background.
When discrete masses can be seen, they are basically yellow-white, punctuated sometimes by areas of hemorrhage or necrosis.
Hepatocellular carcinoma sometimes takes on a green hue when composed of well-differentiated hepatocytes capable of secreting bile.
All patterns of hepatocellular carcinoma have a strong propensity for invasion vascular channels. Hepatocellular carcinoma range from well-differentiated to highly anaplastic undifferentiated lesions.
In well-differentiated and moderately well-differentiated tumors, cells recognizable as hepatocytic in origin are disposed either in a trabecular pattern or in an acinar, pseudoglandular pattern.
Supporting connective tissue is minimal to absent, explaining the soft consistency of most hepatocellular carcinoma. Bile may occasionally be seen in canalicular spaces or lumens between tumor cells, and bile canaliculi may be present ultrastructurally.
A distinctive variant of hepatocellular carcinoma is the fibrolamellar carcinoma. This tumor occurs in young men and women (20 to 40 years of age) with equal incidence, has no association with HBV or cirrhosis factors, and has a distinctly better prognosis. It usually constitutes a single large, hard “scirrhous” tumor with fibrous bands coursing through it. Histologically it is composed of well-differentiated polygonal cells growing in nests or cords and separated by parallel lamellae of dense collar bundles, hence the name “fibrolamellar.”
2. Cholangiocarcinomas resemble adenocarcinomas arising in other parts of the body.
Cholangiocarcinomas are rarely bile stained because differentiated bile duct epithelium does not synthesize pigmented bile.
Most are well-differentiated sclerosing adenocarcinomas with clearly defined glandular and tubular structures lined by somewhat anaplastic cuboidal to low columnar epithelial cells. These neoplasms are often markedly desmoplastic; so dense collagenous stroma separates the glandular elements. Mucus is frequently present within cells and the lumina but not bile.
Tumors of the adrenal medulla
The two principal types of tumour of the adrenal medulla are pheochromocytomas (occurring in adults) and neuroblastomas (occurring in children).
Pheochromocytoma consists of secreting cells of the adrenal medull. It produces high levels of adrenaline/noradrenaline hormones and their breakdown products, vanyl mandelic acid (VMA) and homovanillic acid (HVA), both of which are excreted in the urine and can be estimated as a diagnostic test.
Macroscopically, the tumor is usually spherical and less than 5 cm in diameter, it has a pale, creamy cut surface that changes to dark brown almost instantly when exposed to air, due to oxygenation of tumor pigments. Despite the fact that the tumor is usually small and non-metastatic, it is a hazardous condition with high perioperative mortality.
The excessive amine production produces hypertension that is often initially paroxysmal and associated with severe headaches, but the hypertension eventually becomes constant.
There may be intractable, and often unexplained, cardiac failure.
Pheochromocytoma is one of the causes of surgically treatable systemic hypertension.
Thyroid cancer
There are four main types of malignant tumor derived from thyroid follicle cell.
The most common type is papillary carcinoma, a well-differentiated tumor that arises most frequently in young adults. It is often multifocal within the thyroid, and tends to metastasize via lymphatics to nodes in the neck. It is slow-growing and has an excellent prognosis; even metastatic tumors grow slowly and can be cured by surgical resection.
Follicular carcinoma most commonly affects middle-aged people. Metastasizing via the bloodstream, it is one of the tumors that characteristically spread to bone. Patients may occasionally present with a spontaneous fracture due to metastatic disease, before the primary tumor is detected. It has a good prognosis.
Medullary carcinoma is a less frequent derived from parafolicular or C-cells and characterised by fibrovascular septa and amyloid-conteining stroma, irregular calcification, atypical cells.
Entirely confined to the elderly, anaplastic carcinoma grows very rapidly, extensively invading tissues near the thyroid, such as the trachea and soft tissues of the neck. It may present with a rapidly enlarging thyroid mass causing tracheal compression or jugular vein invasion. The prognosis is very poor. The cells of the tumor, which are usually small, undifferentiated and round, must be distinguished histologically from malignant lymphoma; the latter can also affect the thyroid in the elderly, but is more responsive to treatment.
Pancreatic islet cell tumors
Islet cell tumors may be hormonally inactive or may produce hyperfunction.
These tumors make one or more of the following: glucagon, insulin, gastrin, somatostatin, vasoactive intestinal polypeptide (VIP), pancreatic polypeptide (PP).
The tumors are usually slow-growing, even when malignant (10% of total, higher for glucagonomas, gastrinomas, ACTH-omas and somatostatinomas).
The surrounding pancreatic islets may show hyperplasia,
Metastatic spread remains the only reliable criterion for malignancy in these tumors.
They are named according to their histogenesis:
Beta cell tumors ("insulinomas")
the most common islet cell tumors (* but their incidence is only about 1 in 1,000,000 people)
Look for Whipple's triad:
1. low measured plasma glucose (hypoglycemia);
2. mental changes, especially related to fasting or exercise;
3. attacks relieved by glucose administration.
Often, patients become massively obese.
The etiology of these tumors is obscure; there's not even an important genetic syndrome.
Of beta-cell tumor patients, 70% have a solitary adenoma, while the rest have either hyperplasia of many islands, or a beta cell carcinoma.
Grossly: usually solitary and well-encapsulated. Size from0/5 to 10cm.
Microscopically: cords and sheets of well-differentiated B-cells which do not differ from normal cells.
Many mesotheliomas and retroperitoneal fibrosarcomas, and occasionally other tumors, produce an insulin-like activity (probably somatomedin, but it varies).
Gastrinomas (Zollinger-Ellison Syndrome; "G-cell tumors")
An especially troublesome syndrome of multiple bleeding ulcers and diarrhea. The majority of gastrinomas are low-grade malignancies. May be benign and malignant.
Gastrinomas occur in the wall of the duodenum.
High basal acid secretion plus a marked increased in serum gastrin levels in response to secretin administration strongly suggests gastrinoma.
Glucagonomas ("alpha-two cell tumors"). These produce mild diabetes, sore tongue, and necrolytic migratory erythema. Don't miss this diagnosis.
Delta cell tumors ("somatostatinomas"): diabetes, diarrhea, gallstones, etc.
Tumors secreting vasoactive intestinal polypeptide ("VIPomas"; "Verner-Morrison syndrome"): pancreatic cholera (horrible diarrhea), loss of potassium, achlorhydria -- excellent response to somatostatins.
PP-omas ("P-cell tumors"): no syndrome despite huge amounts of pancreatic polypeptide
Multiple Endocrine Neoplasia Syndromes ("MEN", formerly "MEA", adenomas): some or all of the following in same family:
Wermer's MEN I: pituitary adenoma, parathyroid adenoma, Zollinger-Ellison
Sipple's MEN II(a): Parathyroid adenoma, pheochromocytoma, medullary carcinoma of the thyroid
MEN IIb/III: Medullary carcinoma of the thyroid, pheochromocytoma, mucosal neuromas, Marfanoid habitus.
MESENCHYMAL TUMORS
In ontogenesis, mesenchyma gives the beginning to
1) connective tissue,
2) vessels,
3) muscles,
4) tissues of musculoskeletal system,
5) serous membranes,
6) hemopoietic system.
Mesenchymal tumors develop from
1) connective (fibrous) tissue,
2) fat tissue,
3) muscular tissue,
4) blood and lymphatic vessels,
5) synovial tissue,
6) mesothelial tissue,
7) bone tissue.
They may be benign (name of the tissue + oma) and malignant (name of the tissue + sarcoma). There are also special terms (e.g. desmoid, granular-cell tumor).
Connective (fibrous) tissue tumors
Main benign connective (fibrous) tissue tumors
1) Fibroma - a node of differentiated connective tissue with different direction of the bands:
Dense -fibrous structures prevail over the cellular elements.
Soft (loose connective tissue with great amount of stroma cells -fibroblasts and fibrocytes).
Localization of fibroma is various: skin, breast.
2) Desmoid fibroma is a kind of dense fibroma and characterized by infiltrating growth and relapses. It is composed of banal, “tame-looking” fibroblasts that do not metastasize. More often it is located on the anterior abdominal wall.
3) Dermatofibroma (histiocytoma) - small fibrous node with yellow-brown color. More often it is located in the skin of the legs. Histologically, dermatofibromas are composed of intertwined and anastomosing bundles of fibroblasts surrounded by dense collagen. There are giant polynuclear cells with lipids and hemosiderin between cells.
Malignant connective (fibrous) tissue tumors
Macroscopically sarcoma looks like “fish flesh”. As a rule sarcoma metastases are disseminated hematogenically. Tumors are characterized by atypical cells, including loss of the structure.
1) Fibrosarcoma occurs in deep soft tissue sites, showing increased fibroblastic cells, anaplasia, and abundant mitotic figures. It looks like node or encapsulated formation. There are 3 types of fibrosarcoma:
Differentiated fibrosarcoma is characterized by prevalence of fibrous component over cellular component.
Poorly differentiated fibrosarcoma, termed cellular sarcoma. It is characterized by prevalence of cellular component over fibrous component. It produces metastases more frequently.
Round-cell tumors of unknown origin, termed unclassified tumor.
2) Dermatofibrosarcoma protruberans (malignant histiocytoma)
It is essentially a well-differentiated, slow-growing fibrosarcoma of the skin. It is locally aggressive but rarely metastasizes.
Grossly, they are multilobulated gray-white, fleshy, infiltrative, and unencapsulated but deceptively circumscribed.
Microscopically, there are cellular neoplasm composed of radially oriented (“storiform”) fibroblasts, showing spindled and polygonal cells; mitoses are not as numerous as in fibrosarcoma.
The overlying epidermis is thinned and there often is microscopic extension into subcutaneous fat.
Tumors of fatty tissue
Benign:
1. Lipoma
It is the most frequent soft tissue tumors, arising in subcutaneous regions at any site but most commonly on the back, shoulder, and neck.
They can also arise in the mediastinum, retroperitoneum, or bowel wall.
It may develop in every site where there is fat tissue.
Lipomas are encapsulated, usually small yellow node.
Intramuscular infiltrating lipoma is a tumor without distinct (clear) borders, it infiltrates to intermuscular connective tissue.
2. Hybernoma is a rare tumor of brown fat and consists of large round cells with granular or foamy cytoplasm (fat vacuoles).
Malignant:
1. Liposarcoma (lipoblastic myoma) is a rare, large tumor, which is composing of lipocytes of different degree of maturity and lipoblasts. There are several types of liposarcoma:
Well differentiated (lipoma-like) liposarcoma.
Myxoid (embryonic) liposarcoma tend to be low-grade tumors, which are stubbornly recurrent, follow a more protracted course, and metastasize late.
Round-cell liposarcoma.
Pleomorphic liposarcoma are high-grade, aggressive sarcomas (85-90% metastasize).
2. Malignant hybernoma is a very rare tumor with cellular polymorphism and a lot of giant cells.
Tumors of the muscles
Benign:
1. Leiomyoma
Leiomyoma consists of smooth muscle with chaotic (confused) location of the muscular tissue bands, the stroma with vessels and nerves.
If stroma prevails this tumor is termed fibromyoma.
Leiomyomas occur predominantly in the female genital tract, but they may also occur at other body sites where smooth muscle is well represented (scrotum, nipple, bowel wall).
Secondary changes: necrosis, hemorrhages, cysts, hyalinosis, petrifaction are characterized for leiomyomas.
2. Rhabdomyoma
Rhabdomyoma consists of striated muscles. It resembles embryonic muscular fibers and myoblasts.
It appears against a background of tissue shifts and is accompanied by other development defects (large masses of striated muscles).
The tumors are most frequently primary tumor of the heart in infants and children and are frequently discovered in the first years of life because it leads to obstruction of valve orifice or cardiac chamber.
3. Granular-cell tumor (Abrikosov's tumor): this is small tumor in a capsule. It is located in the tongue, esophagus, and skin. The cells have round shape, large with granular cytoplasm (no lipids).
Malignant:
1. Leiomyosarcoma (malignant leiomyoma) with cellular and tissue atypism, a large number of mitoses (high mitotic index) are characteristic. These rare tumors arise in the skin, deep soft tissues, the stomach and particularly in the uterus from pre-existing myomas.
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