Table 2.

Treatment strategy for malignant and benign neoplasms in patients with MEN1 recommended by Japan Neuroendocrine Tumor Society (JNETS) Guidelines [6]

Pancreas

Multiple nonfunctioning micro- or macro-NETs exist diffusely throughout the whole pancreas. The malignant potential of these NETs increases with their size

Indications for resection of these NETs are a size of 2 cm or more in diameter and rapid growth. The JNETS guidelines recommend avoiding total pancreatectomy when possible, to preserve the pancreatic endocrine function

Thymus

NETs and neuroendocrine carcinoma (NECs) of the thymus are highly malignant

Curative resection with dissection of the regional lymph nodes of any size is recommended

Parathyroid

Hyperparathyroidism (HPT) caused by hyperplasia of the parathyroid glands occurs in more than 90% of MEN1 patients and results in hypercalcemia

Total parathyroidectomy with transplantation or subtotal parathyroidectomy is recommended. For patients with ZES, surgery for HPT is usually performed prior to surgery for gastrinomas

Pituitary

Most tumors are benign and slow growing

Observation or medical treatment is usually recommended, with resection generally only recommended for occasional symptomatic tumors