A<unk>  is a tumor of the alpha cells of the pancreas that results in overproduction of the hormone glucagon.<unk>  was first described in 1942 by Becker.  On microscopic examination,<unk> s consist of pleomorphic cells containing granules that stain for other peptides, most frequently pancreatic polypeptide. Immunoperoxidase staining can detect glucagon within the tumor cells and glucagon. Similar symptoms are present in cases of pseudo-glucagonoma syndrome in the absence of a glucagon-secreting tumor.<unk>  must be differentiated from certain skin lesions (acrodermatitis enteropathica, psoriasis, pellagra, eczema) and other causes of hyperglucagonemia (infection, diabetes mellitus, Cushing syndrome, renal failure, acute pancreatitis, severe stress, and prolonged fasting). The incidence of<unk>  is approximately 0.0005 per 100,000 individuals worldwide.<unk>  affects men and women equally. The median age at diagnosis of<unk>  is 52.5 years. The most potent risk factor in the development of<unk>  is a positive family history of multiple endocrine neoplasia type 1. If left untreated, patients with<unk>  may progress to develop necrolytic migratory erythema, cheilosis, stomatitis, diarrhea, polyuria, and polydipsia.The presence of metastasis is associated with a particularly poor prognosis among patients with<unk> . The 10-year event-free survival rate is less than 51.6% with metastasis and 64.3% without metastasis. According to The American Joint Committee on Cancer (AJCC), there are four stages of<unk>  based on the TNM staging system. Symptoms of<unk>  include necrolytic migratory erythema, cheilosis, stomatitis, diarrhea, polyuria, and polydipsia. A positive family history of multiple endocrine neoplasia type 1 may be present. Common physical examination findings of<unk>  include tachycardia, fever, rash, muscle atrophy, cotton wool spots, flame hemorrhage, and dot and blot hemorrhage on fundoscopic examination of the eye may be present. Laboratory findings consistent with the diagnosis of<unk>  include serum glucagon concentration of 1000pg/ml or greater. Findings on abdominal CT scan suggestive of<unk>  include reinforced mass in the arterial phase of the enhanced CT scan. Abdominal MRI is helpful in the diagnosis of<unk> . On abdominal MRI,<unk>  is characterized by a mass which is hypointense on T1-weighted MRI and hyperintense on T2-weighted MRI. The abdominal ultrasound scan may be helpful in the diagnosis of<unk> . Findings on ultrasound scan suggestive of<unk>  is a hypoechoic tumor in the distal pancreas. Other imaging studies for<unk>  include positron emission tomography scan and somatostatin receptor scintigraphy. Other diagnostic studies for<unk>  includes biopsy, which demonstrates epidermal necrosis, subcorneal pustules, either isolated or associated with necrosis of the epidermis, confluent parakeratosis, epidermal hyperplasia, and marked papillary dermal angioplasia and suppurative folliculitis. The predominant therapy for<unk>  is surgical resection. Adjunctive chemotherapy may be required. Surgery is the mainstay of treatment for<unk> . The feasibility of surgery depends on the stage of<unk>  at diagnosis. Secondary prevention measures of<unk>  include routine glucagon levels and imaging at scheduled intervals after treatment.
Glucagonoma
Insulinoma
VIPoma
Idiopathic hypoglycemia
Gastrinoma
Congenital hyperinsulinism
Granular cell tumor
ACTH-secreting tumor