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pituitary adenoma. Fifteen percent of patients with MEN1 syndrome may pres-
ent with prolactinoma as the first manifestation. Despite aggressive nature of
these tumors, pituitary carcinoma is rare. D 2 receptor agonists are effective in
patients with prolactinoma; however, patients with somatotropinoma require
transsphenoidal surgery followed by somatostatin analogues and/or Υ-knife for
residual disease. On immunohistochemistry, plurihormonal expression is more
frequent in MEN1-associated pituitary tumor compared with non-MEN1 pitu-
itary tumor.- What are the characteristics of insulinoma associated with MEN1 syndrome?
Insulinoma may be the first presenting manifestation of MEN1 in 10 % of
patients. The age of presentation of MEN1-associated insulinoma is <40 years
(usually <20 years), while the majority of patients with non-MEN1 insulinoma
present beyond 40 years of age. In 10 % of patients with MEN1, insulinoma is
associated with other pancreatic NET. They are usually single, size >5 mm, and
benign. Biochemical testing and imaging modalities for the diagnosis are simi-
lar as in patients with sporadic insulinoma.- What are the cutaneous manifestations of MEN1 syndrome?
Cutaneous manifestations in patients with MEN1 syndrome include lipomas,
facial angiofibromas, and collagenomas. Lipomas are present in 30 % of
patients and are frequently multiple. The usual sites of distribution of lipoma
include subcutaneous tissue, visceral tissue, pleura, and retroperitoneum. They
characteristically do not recur after surgery. Angiofibromas and collagenomas
are present in 70–80 % of patients with MEN1 syndrome. These cutaneous
markers may appear even prior to the endocrine organ involvement and may be
a clue to the diagnosis during presymptomatic phase in relatives of patients
with MEN1 syndrome (Fig. 11.2).Fig. 11.2 Collagenoma in a patient with MEN1 syndrome
11 Multiple Endocrine Neoplasia