What is the most likely diagnosis for a clinically obese 12 year old boy with purple striae and a history of renal transplant?

In this scenario, the most likely diagnosis is Cushing's syndrome, especially considering the combination of clinical obesity, the presence of purple striae, and the patient’s history of renal transplant.

Cushing's syndrome is characterized by excess cortisol in the body, which can result from various causes, including adrenal tumors, pituitary adenomas, or, in cases of renal transplant, the use of corticosteroids as part of immunosuppressive therapy. The symptoms associated with Cushing's, such as obesity, striae, hypertension, and changes in glucose metabolism, would align well with the symptoms presented by the patient.

Purple striae, in particular, are a classic sign of Cushing's syndrome and arise due to the weakening of the skin's support structure from excessive cortisol. These striae are wider and more prominent than those commonly seen in normal weight gain and are typically located on the abdomen, thighs, and breasts due to rapid changes in body composition and skin stretching.

While other conditions presented in the choices have their own specific features, they do not account for the constellation of symptoms observed in this patient as effectively as Cushing's syndrome does. For instance, congenital hypothyroidism would typically present with growth delays and may not lead to purple str