Cutaneous lesion associated with multiple endocrine neoplasia type 2A: lichen amyloidosis or notalgia paresthetica?

Three patients of a French family demonstrated an association of multiple endocrine neoplasia type 2A (MEN 2A) with a pruritic scapular skin lesion. The lesions are similar to those described as familial cutaneous lichen amyloidosis in unrelated MEN 2A and medullary thyroid carcinoma families, but histological, immunohistochemical, and ultrastructural analysis of skin biopsies from each patient in the French family did not show amyloid deposition. The topography of the lesion follows dermatomes C8-D3. The patients report not only pruritus but also paresthesia and hyperalgesia, and one showed touch hypoesthesia and pain hyperesthesia in the area of the lesion. Such an association of cutaneous and neurological features suggests notalgia paresthetica (NP), a neuropathy of the posterior dorsal rami nerves. We thus suggest that the cutaneous lesions associated with MEN 2A might be secondary to pathology in the neural crest-derived dorsal sensory nerves. The amyloid, when present, would be secondary to scratching. We propose that patients presenting with familial NP be suspect for MEN 2A.