Multiple endocrine neoplasia type 2B is a rare disorder in which aggressive medullary thyroid cancer, pheochromocytoma may lead to life-threatening blood pressure changes, and mucosal neuromas are included in the clinical presentation. The majority of patients develop symptoms by the first few years of age. Through laboratory, imaging, and genetic studies, the diagnosis must be made early on in order to prevent complications.
Two multiple endocrine neoplasia (MEN) syndromes are described in the literature - MEN 1 and MEN 2, and multiple endocrine neoplasia type 2B, is one of the subtypes of MEN 2, presenting with several distinguishing features     :
In addition, other prominent findings are gastrointestinal complaints (feeding difficulties, vomiting, dysphagia, abdominal pain, and either constipation or diarrhea, presumably arising from excessive calcitonin secretion due to MTC), musculoskeletal changes (kyphosis, hip dislocation, a Marfanoid appearance, as well as flat foot and pes cavus), and a flat facies with hypertelorism   
The diagnosis of MEN type 2B rests on the ability of the physician to recognize the main signs and symptom that will raise clinical suspicion. Firstly, a detailed patient history and a thorough physical examination should be performed, during which mucosal neuromas must be identified. Although MEN syndromes exhibit an autosomal dominant pattern of inheritance (meaning that a family history can be crucial for making the diagnosis), many patients develop de novo mutations of the RET proto-oncogene, the main event in the pathogenesis of multiple endocrine neoplasia type 2B  . As soon as clinical evidence is obtained, laboratory and imaging studies need to be performed. Serum levels of calcitonin and metanephrines (although urine can be a viable sample for the latter) are useful initial methods to suspect toward MTC and pheochromocytoma, respectively   . Computed tomography (CT) and magnetic resonance imaging (MRI) are recommended for internal organ evaluation and confirmation of the two tumors in the patients, whereas barium enema and other radiographic studies of the gastrointestinal tract commonly may reveal a megacolon and dilation of the small bowel   . MTC should be further solidified by performing a biopsy with subsequent histopathological examination and immunohistochemistry .