If a patient displays congenital melanocytic nevi or giant congenital melanocytic nevi, the criteria for diagnosis of neurocutaneous melanosis is as follows:

- Melanocytic deposits exist within the central nervous system that are either malignant or benign

- The cutaneous lesions, giant or otherwise, are not malignant

This criteria is typically validated through biopsy of the cutaneous lesions and imaging of the central nervous system. It is important to establish that the cutaneous lesions are benign. If not, then the melanocytic deposits in the central nervous system may be the result of metastasis of cutaneous melanoma and not neurocutaneous melanosis.

Imaging has been shown to be the only reliable detection method for the presence of neurocutaneous melanosis that can be performed in living patients. Currently, the preferred imaging modality for diagnosis of neurocutaneous melanosis is Magnetic Resonance Imaging, although ultrasound is another viable option. The signal due melanin deposits in the leptomeninges typical of neurocutaneous melanosis can be easily detected in MRI scans of patients under four months old. In patients above this age, there is some suggestion that normal brain myelination may partially obscure these signals.

As most patients with neurocutaneous melanosis are asymptomatic, those who are diagnosed through MR imaging are not guarantied to develop symptoms. Those diagnosed who did not develop symptoms ranged from 10% to 68%. This wide range is most likely due to the large number of asymptomatic, undiagnosed patients with neurocutaneous melanosis.

The majority of patients with neurocutaneous melanosis are asymptomatic and therefore have a good prognosis with few complications. Most are not diagnosed, so definitive data in not available. For symptomatic patients, the prognosis is far worse. In patients without the presence of melanoma, more than 50% die within 3 years of displaying symptoms. While those with malignancy have a mortality rate of 77% with most patients displaying symptoms before the age of 2.

The presence of a Dandy-Walker malformation along with neurocutaneous melanosis, as occurs in 10% of symptomatic patients, further deteriorates prognosis. The median survival time for these patients is 6.5 months after becoming symptomatic.

Most common primary anterior mediastinal tumor (20%) in adults but rarely seen in children. It can be classified as lymphocytic, epithelial, or spindle cell histologies, but the clinical significance of these classifications is controversial. Tonofibrils seen under electron microscopy can differentiate thymoma from other tumors such as carcinoid, Hodgkin's, and seminoma. Patients are usually asymptomatic but can present with myasthenia gravis-related symptoms, substernal pain, dyspnea, or cough. Invasive tumors can produce compression effects such as superior vena cava syndrome. (3,4) Thymomas are diagnosed with CT or MRI revealing a mass in anterior mediastinum. Therapy in stage I tumors consists of surgical resection with good prognosis. Stage II-III requires maximal resection possible followed by radiation. Stage IV disease requires addition of cisplatin-based chemotherapy in addition to those in stage II and III. For those with invasive thymoma, treatment is based on induction chemotherapy, surgical resection, and post-surgical radiation. 5-year survival for invasive thymoma is between 12-54% regardless of any myasthenia gravis symptoms (5,6).

Second most common primary anterior mediastinal mass in adults. Most are seen in the anterior compartment and rest are seen in middle compartment. Hodgkin's usually present in 40-50's with nodular sclerosing type (7), and non-Hodgkin's in all age groups. Can also be primary mediastinal B-cell lymphoma with exceptionally good prognosis. Common symptoms include fever, weight loss, night sweats, and compressive symptoms such as pain, dyspnea, wheezing, Superior vena cava syndrome, pleural effusions (10,11). Diagnosis usually by CT showing lobulated mass. Confirmation done by tissue biopsy of accompanying nodes if any, mediastinoscopy, mediastinotomy, or thoracotomy. FNA biopsy is usually not adequate. (12,13,14) Treatment of mediastinal Hodgkin's involves chemotherapy and/or radiation. 5 year survival is now around 75%. (15) Large-cell type may have somewhat better prognosis. Surgery is generally not performed because of invasive nature of tumor.

Of all cancers involving the same class of blood cell, 2% of cases are mediastinal large B cell lymphomas.

Screening for melanoma in FAMMM kindreds should begin at age 10 with a baseline total body skin examination including scalp, eyes, oral mucosa, genital area, and nail, as family members may develop melanoma in their early teens.

At Mayo Clinic, FAMMM patients with a confirmed mutation and family history of pancreatic cancer are offered screening with either high-resolution pancreatic protocol CT, MRI, or endoscopic ultrasound starting at age 50 or 10 years younger than the earliest family member with pancreas cancer. They are counseled on the lack of evidence-based data to support screening, and on the limitations of our current technology to detect a lesion at a stage amenable to therapy.

Differential diagnosis of this condition includes the Birt-Hogg-Dubé syndrome and tuberous sclerosis. As the skin lesions are typically painful, it is also often necessary to exclude other painful tumors of the skin (including blue rubber bleb nevus, leiomyoma, eccrine spiradenoma, neuroma, dermatofibroma, angiolipoma, neurilemmoma, endometrioma, glomus tumor and granular cell tumor; the mnemonic "BLEND-AN-EGG" may be helpful). Other skin lesions that may need to be considered include cylindroma, lipoma, poroma and trichoepithelioma; these tend to be painless and have other useful distinguishing features.

The skin lesions may be difficult to diagnose clinically but a punch biopsy will usually reveal a Grenz zone separating the tumour from the overlying skin. Histological examination shows dense dermal nodules composed of elongated cells with abundant eosinophilic cytoplasm arranged in fascicles (spindle cells). The nuclei are uniform, blunt-ended and cigar-shaped with only occasional mitoses. Special stains that may be of use in the diagnosis include Masson's trichrome, Van Gieson's stain and phosphotungstic acid–haematoxylin.

The renal cell carcinomas have prominent eosinophilic nucleoli surrounded by a clear halo.

Large and especially giant congenital nevi are at higher risk for malignancy degeneration into melanoma. Because of the premalignant potential, it is an acceptable clinical practice to remove congenital nevi electively in all patients and relieve the nevocytic overload.

Clinical diagnosis can be made with the naked eye using the ABCD guideline or by using dermatoscopy. An online-screening test is also available to help screen out benign moles.

The treatment of a Pancoast lung cancer may differ from that of other types of non-small cell lung cancer. Its position and close proximity to vital structures (such as nerves and spine) may make surgery difficult. As a result, and depending on the stage of the cancer, treatment may involve radiation and chemotherapy given prior to surgery (neoadjuvant treatment).

Surgery may consist of the removal of the upper lobe of a lung together with its associated structures (subclavian artery, vein, branches of the brachial plexus, ribs and vertebral bodies), as well as mediastinal lymphadenectomy. Surgical access may be via thoracotomy from the back or the front of the chest and modifications

Nevi are typically diagnosed clinically with the naked eye or using dermatoscopy. More advanced imaging tests are available for distinguishing melanocytic nevi from melanoma, including computerized dermoscopy and image analysis. The management of nevi depends on the type of nevus and the degree of diagnostic uncertainty. Some nevi are known to be benign, and may simply be monitored over time. Others may warrant more thorough examination and biopsy for histopathological examination (looking at a sample of skin under a microscope to detect unique cellular features). For example, a clinician may want to determine whether a pigmented nevus is a type of melanocytic nevus, dysplastic nevus, or melanoma as some of these skin lesions pose a risk for malignancy. The ABCDE criteria (asymmetry, border irregularity, color variegation, diameter > 6 mm, and evolution) are often used to distinguish nevi from melanomas in adults, while modified criteria (amelanosis, bleeding or bumps, uniform color, small diameter or de novo, and evolution) can be used when evaluating suspicious lesions in children. In addition to histopathological examination, some lesions may also warrant additional tests to aid in diagnosis, including special stains, immunohistochemistry, and electron microscopy. Typically; the nevi which exist since childhood are harmless

The diagnosis of a mediastinal germ cell tumor should be considered in all young males with a mediastinal mass. In addition to physical examination and routine laboratory studies, initial evaluation should include CT of the chest and abdomen, and determination of serum levels of HCG and alpha-fetoprotein.

Benign congenital nevi can have histological characteristics resembling melanomas, often breaking most if not all of the ABCDE rules. Dermatoscopic findings of the smaller forms of benign congenital nevi can aid in their differentiation from other pigmented neoplasms.

Microscopically, congenital melanocytic nevi appear similar to acquired nevi with two notable exceptions. For the congenital nevus, the neval cells are found deeper into the dermis. Also, the deeper nevus cells can be found along with neurovascular bundles, with both surrounding hair follicles, sebaceous glands, and subcutaneous fat. Such annexes and the hypodermis can also be hypoplasic or, conversely, present aspects of hamartoma.

Following thoracoabdominal trauma, most commonly a penetrating injury, laceration of the diaphragm, and spleen allows ectopic splenic tissue to reach the pleural space of the lung.

Affected persons are usually asymptomatic. However, on rare occasions, thoracic splenosis can present with chest pain and/or hemoptysis.

On radiological studies, thoracic splenic lesions are visualized using CT scans. Visualized lesions can be described as solitary or multiple nodules. The locations of the lesions are mostly in the lower left pleural space and/or splenic bed. Confirmation can be done using scintigraphy with 99mTc tagged heat-damaged red blood cells.

No treatment is required since thoracic splenosis is a benign condition.

Treatment is by excisional biopsy, wide local excision and possibly sentinel node biopsy. Spread of disease to local lymph nodes or distant sites (typically brain, bone, skin and lung) marks a decidedly poor prognosis.

It often requires a dermatologist to fully evaluate moles. For instance, a small blue or bluish-black spot, often called a blue nevus, is usually benign but often mistaken for melanoma. Conversely, a junctional nevus, which develops at the junction of the dermis and epidermis, is potentially cancerous.

A basic reference chart used for consumers to spot suspicious moles is found in the mnemonic A-B-C-D, used by institutions such as the American Academy of Dermatology and the National Cancer Institute. The letters stand for asymmetry, border, color, and diameter. Sometimes, the letter E (for elevation or evolving) is added. According to the American Academy of Dermatology, if a mole starts changing in size, color, shape or, especially, if the border of a mole develops ragged edges or becomes larger than a pencil eraser, it would be an appropriate time to consult with a physician. Other warning signs include a mole, even if smaller than a pencil eraser, that is different from the others and begins to crust over, bleed, itch, or become inflamed. The changes may indicate developing melanomas. The matter can become clinically complicated because mole removal depends on which types of cancer, if any, come into suspicion.

A recent and novel method of melanoma detection is the "ugly duckling sign" It is simple, easy to teach, and highly effective in detecting melanoma. Simply, correlation of common characteristics of a person's skin lesion is made. Lesions which greatly deviate from the common characteristics are labeled as an "ugly duckling", and further professional exam is required. The "little red riding hood sign", suggests that individuals with fair skin and light colored hair might have difficult-to-diagnose melanomas. Extra care and caution should be rendered when examining such individuals as they might have multiple melanomas and severely dysplastic nevi. A dermatoscope must be used to detect "ugly ducklings", as many melanomas in these individuals resemble non-melanomas or are considered to be "wolves in sheep clothing". These fair skinned individuals often have lightly pigmented or amelanotic melanomas which will not present easy-to-observe color changes and variation in colors. The borders of these amelanotic melanomas are often indistinct, making visual identification without a dermatoscope very difficult.

People with a personal or family history of skin cancer or of dysplastic nevus syndrome (multiple atypical moles) should see a dermatologist at least once a year to be sure they are not developing melanoma.

The management of a nevus depends on the specific diagnosis, however, the options for treatment generally include the following modalities:

Congenital anomaly causes abnormal proliferation and dilation of lymphatic channels.

Affected persons are usually young adults that present with progressive dyspnea.

On radiological studies, diffuse lesions are visualized throughout the thoracic cavity using CT scans. The location of the lesions is mostly in the upper lobes of the lungs, usually in a lymphatic distribution. Thickening of the pleura and interlobular septal is also evident. In addition, pleural/pericardial effusions and mediastinal fat infiltration is appreciated. Definitive diagnosis is achieved through tissue biopsy.

Thoracocentesis and pericardiocentesis are performed to remove excess fluid. There is evidence in the literature that chemotherapy and radiation therapy helps to improve symptoms.

Some patients have a few or no histopathologic abnormalities. Histological examination of a biopsy may show an increase in the number and size of capillaries and veins (rarely lymphatics), dilated capillaries located in the deeper dermis, and hyperplasia and swollen endothelial cells with occasional dilated veins and venous lakes.

Ferner et al. give the following diagnostic criteria for Schwannomatosis:

- Definite

- Age >30 years and ≥2 nonintradermal schwannomas, at least one with histologic confirmation and no evidence of vestibular tumor on MRI scan and no known NF mutation, or

- One nonvestibular schwannoma plus a first-degree relative with schwannomatosis

- Possible

- Age <30 and ≥2 nonintradermal schwannomas, at least one with histologic confirmation and no evidence of vestibular tumor on MRI scan and no known NF mutation, or

- Age >45 and ≥2 nonintradermal schwannomas, at least one with histologic confirmation and no symptoms of 8th nerve dysfunction and no NF2, or

- Nonvestibular schwannoma and first-degree relative with schwannomatosis

- Segmental. Diagnosed as definite or possible but limited to one limb or ≤5 contiguous segments of spine.

Another set of criteria are:

- Two or more nonintradermal (cutaneous) schwannomas

- No evidence of vestibular tumor

- No known NF-2 mutation

or

- One pathologically confirmed nonvestibular schwannoma plus a first degree relative who meets the above criteria.

The prognosis is favorable in most patients with an isolated cutaneous abnormality. In the majority of cases, both the vivid red marking and the difference in circumference of the extremities regress spontaneously during the first year of life. It is theorized that this may be due to the normal maturation process, with thickening of the epidermis and dermis. Improvements for some patients can continue for up to 10 years, while in other cases, the marbled skin may persist for the patient's lifetime.

One study reported an improvement in lesions in 46% of patients within 3 years. If CMTC persists into adulthood, it can result in complaints due to paresthesia, increased sensitivity to cold and pain, and the formation of ulcers.

Few reports included long-term follow up of CMTC into adolescence and adulthood. While about 50% of patients seem to show definite improvement in the reticular vascular pattern, the exact incidence and cause of persistent cases are unknown.

The main techniques of diagnosing SVCS are with chest X-rays (CXR), CT scans, transbronchial needle aspiration at bronchoscopy and mediastinoscopy. CXRs provide the ability to show mediastinal widening and may show the presenting primary cause of SVCS. CT scans should be contrast enhanced and be taken on the neck, chest, lower abdomen and pelvis. They may also show the underlying cause and the extent to which the disease has progressed.

Spitz nevi are uncommon. Their annual incidence was estimated in a coastal population of sub-tropical Queensland to be 1.4 cases per 100,000 people. For comparison, the annual incidence of melanoma in the same population, which is high by world standards is 25.4 cases per 100,000 people.

Although they are most commonly found on people in their first two decades of life, the age range for people with Spitz nevi is from 6 months to 71 years, with a mean age of 22 years and a median age of 19 years.

PECs typically stain for melanocytic markers (HMB-45, Melan A (Mart 1), Mitf) and myogenic markers (actin, myosin, calponin).

PECs bear significant histologic and immunohistochemical similarity to:

- angiomyolipoma,

- clear-cell sugar tumour (CCST),

- lymphangioleiomyomatosis, and,

- clear-cell myomelanocytic tumour of ligamentum teres/falciform ligament.

- abdominopelvic sarcoma of perivascular epitheloid cells

- primary extrapulmonary sugar tumour

Thus, it has been advocated that the above could be classified PEComas.

PEComas are rare and can have myriad features; therefore, they can be confused with carcinomas, smooth muscle tumours, adipocytic tumours, clear cell sarcomas, melanomas and gastrointestinal stromal tumours (GIST).