Wilms tumour affects approximately one person per 10,000 worldwide before the age of 15 years. People of African descent may have slightly higher rates of Wilms tumor. The peak age of Wilms tumour is 3 to 4 years and most cases occur before the age of 10 years.

A genetic predisposition to Wilms Tumor in individuals with aniridia has been established, due to deletions in the p13 band on chromosome 11.

Dr. Sidney Farber, founder of Dana-Farber Cancer Institute, and his colleagues achieved the first remissions in Wilms tumor in the 1950s. By employing the antibiotic actinomycin D in addition to surgery and radiation therapy, they boosted cure rates from 40 to 89 percent.

A cystic nephroma, also known as multilocular cystic nephroma, mixed epithelial stromal tumour (MEST) and renal epithelial stromal tumour (REST), is a type of rare benign kidney tumour.

Cystic nephromas are often asymptomatic. They are typically discovered on medical imaging incidentally (i.e. an incidentaloma).

MCACL has a much more favorable prognosis than most other forms of adenocarcinoma and most other NSCLC's. Cases have been documented of continued growth of these lesions over a period of 10 years without symptoms or metastasis. The overall mortality rate appears to be somewhere in the vicinity of 18% to 27%, depending on the criteria that are used to define this entity.

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".

Its cause is unknown, but there is a strong association with cigarette smoking. Smokers are at 8 times greater risk of developing Warthin's tumor than the general population.

As metanephric adenomas are considered benign, they can be left in place, i.e. no treatment is needed.

Although the causes of craniopharyngioma is unknown, it can occur in both children and adults, with a peak in incidence at 9 to 14 years of age. There are approximately 120 cases diagnosed each year in the United States in patients under the age of 19 years old. In fact, more than 50% of all patients with craniopharyngioma are under the age of 18 years. There is no clear association of the tumor with a particular gender or race. It is not really known what causes craniopharyngiomas, but they do not appear to "run in families" or to be directly inherited from the parents.

Mucinous cystadenoma is a benign cystic tumor lined by a mucinous epithelium. It is a type of cystic adenoma (cystadenoma).

Mucinous cystadenoma may arise in a number of locations; however, mucinous cystadenoma at different locations are not generally considered to be related to one another.

Accurate incidence statistics on MCACL are unavailable. It is a very rare tumor, with only a few dozen cases reported in the literature to date.

In the few cases described in the literature to date, the male-to-female ratio is approximately unity, and right lung lesions occurred twice as commonly as left lung lesions. Approximately 2/3 of cases have been associated with tobacco smoking. Cases have been reported in patients as young as 29.

Warthin's tumor, also known as papillary cystadenoma lymphomatosum, is a benign cystic tumor of the salivary glands containing abundant lymphocytes and germinal centers (lymph node-like stroma). It is named for pathologist Aldred Scott Warthin, who described two cases in 1929.

Although often described as benign, a teratoma does have malignant potential. In a UK study of 351 infants and children diagnosed with "benign" teratoma reported 227 with MT, 124 with IT. Five years after surgery, event-free survival was 92.2% and 85.9%, respectively, and overall survival was 99% and 95.1%. A similar study in Italy reported on 183 infants and children diagnosed with teratoma. At 10 years after surgery, event free and overall survival were 90.4% and 98%, respectively.

Depending on which tissue(s) it contains, a teratoma may secrete a variety of chemicals with systemic effects. Some teratomas secrete the "pregnancy hormone" human chorionic gonadotropin (βhCG), which can be used in clinical practice to monitor the successful treatment or relapse in patients with a known HCG-secreting teratoma. This hormone is not recommended as a diagnostic marker, because most teratomas do not secrete it. Some teratomas secrete thyroxine, in some cases to such a degree that it can lead to clinical hyperthyroidism in the patient. Of special concern is the secretion of alpha-fetoprotein (AFP); under some circumstances AFP can be used as a diagnostic marker specific for the presence of yolk sac cells within the teratoma. These cells can develop into a frankly malignant tumor known as yolk sac tumor or endodermal sinus tumor.

Adequate follow-up requires close observation, involving repeated physical examination, scanning (ultrasound, MRI, or CT), and measurement of AFP and/or βhCG.

Embryonal teratomas most commonly occur in the sacrococcygeal region: sacrococcygeal teratoma is the single most common tumor found in newly born humans.

Of teratomas on the skull sutures, approximately 50% are found in or adjacent to the orbit. Limbal dermoid is a choristoma, not a teratoma.

Teratoma qualifies as a rare disease, but is not extremely rare. Sacrococcygeal teratoma alone is diagnosed at birth in one out of 40,000 humans. Given the current human population and birth-rate, this equals five per day or 1800 per year. Add to that number sacrococcygeal teratomas diagnosed later in life, and teratomas in other locales, and the incidence approaches ten thousand new diagnoses of teratoma per year.

Poorly differentiated thyroid carcinoma (PDTC) is malignant neoplasm of follicular cell origin showing intermediate histopathological patterns between differentiated and undifferentiated thyroid cancers.

This is a very rare neoplasm accounting for approximately 0.0003% of all tumors and about 2.5% of all external ear neoplasms. There is a wide age range at initial presentation, although the mean age is about 50 years of age. Females are affected slightly more often (1.5:1).

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.

Craniopharyngiomas are generally benign but are known to recur after resection. Recent research has demonstrated a malignant (but rare) tendency of craniopharyngiomas. These malignant craniopharyngiomas are very rare, but are associated with poor prognosis.

Mucinous cystadenomas make up 15-20% of all ovarian tumors. They often become very large and can extend up into the abdomen.

These tumors are usually evaluated using ultrasound, CT scan, or MRI. Findings on imaging studies are nonspecific. These ovarian tumors are usually multi-septated, cystic masses with thin walls. They also contain varying amounts of solid tissue which consists of proliferating stromal tissue, papillae, or malignant tumor cells.

Benign mucinous cystadenomas compose 80% of mucinous ovarian tumors and 20-25% of benign ovarian tumors overall. The peak incidence occurs between 30-50 years of age. Benign tumors are bilateral in 5-10% of cases.

A struma ovarii (literally: goitre of the ovary) is a rare form of monodermal teratoma that contains mostly thyroid tissue, which may cause hyperthyroidism.

Despite its name, struma ovarii is not restricted to the ovary.

The vast majority of struma ovarii are benign tumors; however, malignant tumors of this type is found in a small percentage of cases.

Lymphangiomas are rare, accounting for 4% of all vascular tumors in children. Although lymphangioma can become evident at any age, 50% are seen at birth, and 90% of lymphangiomas are evident by 2 years of age.

Most frequent in middle-aged and older adults (age 40 and above), liposarcomas are the second most common of all soft-tissue sarcomas following malignant fibrous histiocytomas. Annually 2.5 cases occur per million population.

The prognosis for lymphangioma circumscriptum and cavernous lymphangioma is generally excellent. This condition is associated with minor bleeding, recurrent cellulitis, and lymph fluid leakage. Two cases of lymphangiosarcoma arising from lymphangioma circumscriptum have been reported; however, in both of the patients, the preexisting lesion was exposed to extensive radiation therapy.

In cystic hygroma, large cysts can cause dysphagia, respiratory problems, and serious infection if they involve the neck. Patients with cystic hygroma should receive cytogenetic analysis to determine if they have chromosomal abnormalities, and parents should receive genetic counseling because this condition can recur in subsequent pregnancies.

Complications after surgical removal of cystic hygroma include damage to the structures in the neck, infection, and return of the cystic hygroma.

The incidence of bronchiolo-alveolar carcinoma has been reported to vary from 4–24% of all lung cancer patients. An analysis of Surveillance epidemiology and End results registry ( SEER) by Read "et al." revealed that although the incidence of BAC has increased over the past two decade it still constitutes less than 4% of NSCLC in every time interval. This difference in the incidence has been attributed to complex histopathology of cancer. While pure BAC is rare, the increase in incidence as seen in various studies can be due to unclear histological classification till WHO came up with its classification in 1999 and then in 2004.

Another distinguishing feature about BAC is that it afflicts men and women in equal proportions, some recent studies even suggest slightly higher incidence among women.

Ceruminous adenocarcinoma is a malignant neoplasm derived from ceruminous glands of the external auditory canal. This tumor is rare, with several names used in the past. Synonyms have included cylindroma, ceruminoma, ceruminous adenocarcinoma, not otherwise specified (NOS), ceruminous adenoid cystic carcinoma (ACC), and ceruminous mucoepidermoid carcinoma.