Metanephric adenoma (MA)is a rare, benign tumour of the kidney, that can have a microscopic appearance similar to a nephroblastoma (Wilms tumours), or a papillary renal cell carcinoma.

It should not be confused with the pathologically unrelated, yet similar sounding, "mesonephric adenoma".

The symptoms may be similar to those classically associated with renal cell carcinoma, and may include polycythemia, abdominal pain, hematuria and a palpable mass. Mean age at onset is around 40 years with a range of 5 to 83 years and the mean size of the tumour is 5.5 cm with a range 0.3 to 15 cm (1). Polycythemia is more frequent in MA than in any other type of renal tumour. Of further relevance is that this tumour is more commonly calcified than any other kidney neoplasm. Surgery is curative and no other treatment is recommended. There is so far no evidence of metastases or local recurrence.

Nephrogenic adenoma, also mesonephric adenoma and nephrogenic metaplasia, is a benign growth typically found in the urinary bladder.

It is thought to result from displacement and implantation of renal tubular cells, as this entity in kidney transplant recipients has been shown to be kidney donor derived.

This entity should not be confused with the similar-sounding "metanephric adenoma".

A gonadal tissue neoplasm is a tumor having any histology characteristic of cells or tissues giving rise to the gonads. These tissues arise from the sex cord and stromal cells. The tumor may be derived from these tissues, or produce them.

Although the tumor is composed of gonadal tissue, it is not necessarily located in an ovary or testicle.

A gonadal tissue neoplasm should not be confused with a urogenital neoplasm, though the two topics are often studied together. The embryology of the gonads is only indirectly related to the embryology of the external genitals and urinary system.

A ureteral neoplasm is a type of tumor that can be primary, or associated with a metastasis from another site.

Treatment may involve removal of the kidney and ureter, or just the ureter.

Classification of cancers often is oriented around the embryological origin of the tissue. In some contexts, the primary division is at the border of kidney and ureter, and in other contexts, the primary division is between derivatives of the metanephric blastema and those of the ureteric bud. Because of this, neoplasia of the ureters are sometimes grouped with tumors of the renal pelvis.

Pain is the most common symptom, followed by either sensorineural or conductive hearing loss, tinnitus or drainage (discharge). A mass lesion may be present, but it is often slow growing.

Glandular and epithelial neoplasm is a grouping of tumors arising from the glands and epithelium.

An example is adenoma.

An odontogenic tumor is a neoplasm of the cells or tissues that initiate odontogenic processes.

Examples include:

- Adenomatoid odontogenic tumor

- Ameloblastoma, a type of odontogenic tumor involving ameloblasts

- Calcifying epithelial odontogenic tumor

- Keratocystic odontogenic tumor

- Odontogenic myxoma

- Odontoma

Pathologists classify serous cystic neoplasms into two broad groups. Those that are benign, that have not spread to other organs, are designated "serous cystadenoma". Serous cystadenomas can be further sub-typed into microcystic, oligocystic (or macrocystic), solid, mixed serous-endocrine neoplasm, and VHL-associated serous cystic neoplasm. This latter classification scheme is useful because it highlights the range of appearances and the clinical associations of these neoplasms. Serous cystic neoplasms that have spread ("metastasized") to another organ are considered malignant and are designated "serous cystadenocarcinoma".

Patients present with a slow-growing, painless, solitary mass, usually of the subcutaneous tissues. It is much less frequently noted in the intramuscular tissue. It is not uncommon for symptoms to be present for years.

Benign neoplasm with "BROWN FAT" is noted.

Ovarian serous cystadenoma, also (less precisely) known as serous cystadenoma, is the most common ovarian neoplasm, representing 20% of ovarian neoplasms, and is benign.Human Reproduction. University of Utah Medpath http://library.med.utah.edu/kw/human_reprod/seminars/seminar4B2.html.

It has a very superficial resemblance to the most common type of ovarian cancer (serous carcinoma of the ovary) under the microscope; however, (1) it is virtually impossible to mix-up with its malignant counterpart (serous carcinoma), and (2) does not share genetic traits of indeterminate serous tumours, also called "serous borderline tumours", that may transform into serous carcinoma.

Serous cystadenomas (of the ovary) are not related to serous cystadenomas of the pancreas, i.e. the presence of an ovarian "or" pancreatic one does "not" suggest an increased risk for the other one.

The treatment is simple excision and exclusion of a malignant neoplasm.

This lesion has been called a fetal lipoma, lipoma of embryonic fat or a lipoma of immature fat.

Nephrogenic adenomas are diagnosed under the microscope by pathologists. Microscopically the tumor shows closely packed small tubular structures in edematous stroma. The tubules show considerable variation in size and shape resembling convoluted tubules of the kidney. The single layer of cells lining the tubules are cuboidal with a scant to moderate amount of cytoplasm. In some areas they may have a hobnail appearance.

Pancreatic serous cystadenoma, also known as serous cystadenoma of the pancreas and serous microcystic adenoma, a benign tumour of pancreas. It is usually found in the head of the pancreas, and may be associated with von Hippel-Lindau syndrome.

In contrast to some of the other cyst-forming tumors of the pancreas (such as the intraductal papillary mucinous neoplasm and the mucinous cystic neoplasm), serous cystic neoplasms are almost always entirely benign. There are some exceptions; rare case reports have described isolated malignant serous cystadenocarcinomas. In addition, serous cystic neoplasms slowly grow, and if they grow large enough they can press on adjacent organs and cause symptoms.

This tumor only affects the outer 1/3 to 1/2 of the external auditory canal as a primary site. If this area is not involved, the diagnosis should be questioned. The most common tumor type is ceruminous adenoid cystic carcinoma and ceruminous adenocarcinoma, NOS.

Benign and borderline variants of this neoplasm are rare, and most cases are malignant.

These tumors may have a worse prognosis than serous tumors.

Cystadenocarcinoma is a malignant form of a cystadenoma and is a malignant neoplasm derived from glandular epithelium, in which cystic accumulations of retained secretions are formed. The neoplastic cells manifest varying degrees of anaplasia and invasiveness, and local extension and metastases occur. Cystadenocarcinomas develop frequently in the ovaries, where pseudomucinous and serous types are recognized. Similar tumor histology has also been reported in the pancreas, although it is a considerably rarer entity.

It is the most common malignant ovarian tumor. Contains complex multi-loculated cyst but with exuberant solid areas in places. It usually presents with omental metastases which cause ascites.

Swelling is the most common presenting complaint; however, OKCs may be asymptomatic and found incidentally on dental X-rays.

Sebaceous lymphadenoma is a tissue diagnosis, e.g. salivary gland biopsy.

It may be confused with a number of benign and malignant neoplasms, including Warthin tumour, mucoepidermoid carcinoma and sebaceous lymphadenocarcinoma.

Malignant transformation to squamous cell carcinoma may occur, but is unusual.

A urogenital neoplasm is a tumor of the urogenital system.

Types include:

- Cancer of the breast and female genital organs: (Breast cancer, Vulvar cancer, Vaginal cancer, Cervical cancer, Uterine cancer, Endometrial cancer, Ovarian cancer)

- Cancer of the male genital organs (Carcinoma of the penis, Prostate cancer, Testicular cancer)

- Cancer of the urinary organs (Renal cell carcinoma, Bladder cancer)

Typically, they are cystic neoplasms with polypoid masses that protrude into the cyst. On microscopic pathological examination, they are composed of cells with clear cytoplasm (that contains glycogen) and "hob nail" cells (from which the glycogen has been secreted). The pattern may be glandular, papillary or solid.

Intraductal papillary mucinous neoplasm (IPMN) is a type of tumor that can occur within the cells of the pancreatic duct. IPMN tumors produce mucus, and this mucus can form pancreatic cysts. Although intraductal papillary mucinous neoplasms are benign tumors, they can progress to pancreatic cancer. As such IPMN is viewed as a precancerous condition. Once an intraductal papillary mucinous neoplasm has been found, the management options include close monitoring and pre-emptive surgery.

A parathyroid neoplasm is a tumor of the parathyroid gland.

Types include:

- Parathyroid adenoma

- Parathyroid carcinoma