Alternatively, it is proposed that the high levels of ACTH, β-lipotropin, and γ-lipotropin, which contain weak MSH function, can act on the melanocortin 1 receptor. A variant of Cushings disease can be caused by ectopic, i.e. extra pituitary, ACTH production from, for example, a small-cell lung cancer.When Cushings syndrome is caused by an increase of cortisol at the level of the adrenal glands (via an adenoma or hyperplasia), negative feedback ultimately reduces ACTH production in the pituitary. In these cases, ACTH levels remain low and no hyperpigmentation develops. Causes
Cushings syndrome may result from any cause of increased glucocorticoid levels, whether due to medication or internal processes. Some sources however do not consider the glucocorticoid medication-induced condition as "Cushings syndrome" proper, instead using the term "Cushingoid" to describe the medications side effects which mimic the endogenous condition.Cushings disease is a specific type of Cushings syndrome caused by a pituitary tumor leading to excessive production of ACTH (adrenocorticotropic hormone). Excessive ACTH stimulates the adrenal cortex to produce high levels of cortisol, producing the disease state. While all Cushings disease gives Cushings syndrome, not all Cushings syndrome is due to Cushings disease. Several possible causes of Cushings syndrome are known. Exogenous
The most common cause of Cushings syndrome is the use of prescribed glucocorticoids to treat other diseases (iatrogenic Cushings syndrome). Glucocorticoids are used in treatment of a variety of disorders, including asthma and rheumatoid arthritis, and also used for immunosuppression after organ transplants.
An ependymoma is a tumor that arises from the ependyma, a tissue of the central nervous system. Usually, in pediatric cases the location is intracranial, while in adults it is spinal. The common location of intracranial ependymomas is the fourth ventricle. Rarely, ependymomas can occur in the pelvic cavity. Syringomyelia can be caused by an ependymoma. Ependymomas are also seen with neurofibromatosis type II. Signs and symptoms
Source:
severe headache
visual loss (due to papilledema)
vomiting
bilateral Babinski sign
drowsiness (after several hours of the above symptoms)
gait change (rotation of feet when walking)
impaction/constipation
back flexibility

Morphology
Ependymomas are composed of cells with regular, round to oval nuclei. There is a variably dense fibrillary background. Tumor cells may form gland-like round or elongated structures that resemble the embryologic ependymal canal, with long, delicate processes extending into the lumen; more frequently present are perivascular pseudorosettes in which tumor cells are arranged around vessels with an intervening zone consisting of thin ependymal processes directed toward the wall of the vessel.It has been suggested that ependymomas are derived from radial glia, despite their name suggesting an ependymal origin. Ependymoma tumors
Ependymomas make up about 5% of adult intracranial gliomas and up to 10% of childhood tumors of the central nervous system (CNS). Their occurrence seems to peak at age 5 years and then again at age 35.