History
Cutaneous tumors in multiple endocrine neoplasia type 1 (MEN1) are of long duration and generally grow slowly or not at all. This permanence helps differentiate these lesions from inflammatory skin lesions.
Ask patients with the cutaneous abnormalities seen in MEN1 about symptoms of hormone hypersecretion. Ask patients if any family members have similar skin lesions or endocrine tumors. Ask if any family members have tuberous sclerosis.
Physical Examination
In multiple endocrine neoplasia type 1 (MEN1), angiofibromas are telangiectatic, skin-colored, pink or light-brown papules that are 1-4 mm in diameter, as shown in the image below. Approximately 2-50 lesions may be present. They are mostly located on the central part of the face. In separate studies, angiofibromas were reported in 5%, 8%, 22%, 43%, 64%, and 88% of patients with MEN1. [3, 5, 18, 21, 22, 23]

Angiofibromas in patients with MEN1 tend to be smaller in size and less numerous than angiofibromas in patients with tuberous sclerosis. In addition, angiofibromas in MEN1 are common on the upper lip and vermillion border of the lip, whereas angiofibromas in tuberous sclerosis tend to spare the upper lip. The age at onset of angiofibromas is later in MEN1 than in tuberous sclerosis; typically, they occur in the second decade and later in life in MEN1 compared with the first decade of life in tuberous sclerosis. [24] Patients with MEN1 do not exhibit several findings described in tuberous sclerosis, including the forehead plaque, multiple periungual fibromas, and pitting of the teeth.
Collagenomas are skin-colored to slightly hypopigmented, firm, round to oval papules that are 0.2-2 cm in diameter, as shown in the images below. Multiple smaller lesions and/or a few larger lesions may be observed. They are mostly located on the upper part of the trunk and on the neck. They have been reported in 0-72% of patients with MEN1, with 83-91% of patients with collagenomas having multiple lesions. [3, 5, 22, 25, 26]


Lipomas are soft, compressible, subcutaneous nodules that are generally 0.5-5 cm in diameter, as shown in the image below. They are solitary or multiple, and they occur on the trunk, the extremities, and the scalp. Lipomas have been reported in 3-34% of patients with MEN1. [3, 5, 22]

Additional skin findings include café au lait macules; hypopigmented macules, including confettilike hypopigmented macules; gingival papules (see image below); and solitary periungual fibroma.

Solitary hypopigmented macules or café au lait macules are common in the general population and should not be used as markers for MEN1.
Multiple hypopigmented macules or confettilike hypopigmented macules are more commonly observed in persons with tuberous sclerosis but have been observed in patients with MEN1.
Similarly, gingival papules are typically associated with tuberous sclerosis and Cowden syndrome, but they have also been observed in 2 patients with MEN1. [3]
Café au lait macules numbering 3 or less have been seen in patients with MEN1. Six or more café au lait macules indicates neurofibromatosis.
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A 27-year-old man has telangiectatic, red papules on the nose, the nasolabial fold, and the upper lip. Histologic examination of one of these lesions confirmed the clinical diagnosis of angiofibroma. In addition to multiple facial angiofibromas, this patient has multiple collagenomas and gingival papules, as well as hyperparathyroidism and a positive family history for multiple endocrine neoplasia type 1.
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The shoulder of a 65-year-old man shows multiple firm, skin-colored to slightly hypopigmented papules. Biopsy results of the largest lesion revealed collagenoma. Endocrinologic features of multiple endocrine neoplasia type 1 in this patient are hyperparathyroidism and Zollinger-Ellison syndrome. Note that the photograph was taken with side lighting to accentuate the lesions.
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A close-up view of a large collagenoma on the shoulder of a 65-year-old man shows multiple firm, skin-colored to slightly hypopigmented papules. Endocrinologic features of multiple endocrine neoplasia type 1 in this patient are hyperparathyroidism and Zollinger-Ellison syndrome.
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A 39-year-old woman with multiple endocrine neoplasia type 1 has a soft nodule on the forehead that is consistent with lipoma. Lipomas in patients with multiple endocrine neoplasia type 1 can be single or multiple, and they are sometimes large.
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On the attached gingiva of a 27-year-old man with multiple endocrine neoplasia type 1, a few small, whitish papules are present. Gingival papules are a rare and subtle finding in multiple endocrine neoplasia type 1. In addition to multiple facial angiofibromas, this patient has multiple collagenomas, hyperparathyroidism, and a positive family history for multiple endocrine neoplasia type 1.
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Light microscopic evaluation of a section of an angiofibroma shows prominent vessels and concentric rings of collagen around vessels and adnexal structures (hematoxylin and eosin, original magnification X100). These findings are indistinguishable from those observed in angiofibromas in patients with tuberous sclerosis.
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Histologic examination of a collagenoma reveals dense, thick collagen in the reticular dermis (hematoxylin and eosin, original magnification X40). An elastic stain showed reduced elastic fibers (not shown). Biopsy samples of collagenomas can be mistaken for healthy skin unless an elliptical excision containing surrounding healthy skin is obtained for comparison. The contrast with healthy skin accentuates the thickened dermis and collagen alterations seen in collagenomas.