Hereditary localized pruritus in affected members of a kindred with multiple endocrine neoplasia type 2A (Sipple's syndrome).

We describe a kindred with medullary thyroid carcinoma and phaeochromocytoma (MEN 2A or Sipple's syndrome) in which a cutaneous manifestation is only present in affected members. These members felt an intense itching in an area 5-10 cm in length and passing through the scapular region where, after long-term scratching, the skin appears hyperkeratotic and pigmented. Cutaneous biopsies proved negative for dermis nerve abnormality. This restricted itching strongly suggests dominant transmitted hereditary localized pruritus which was described many years ago in a family which was apparently free from inherited diseases. In the examined kindred this skin peculiarity was said to have appeared before the patients reached 10 years of age and, therefore, prior to the biochemical manifestation of the thyroid tumour. Three children of the last generation, aged 4 to 11 years, all of whom presented this cutaneous manifestation, were considered unaffected because of normal basal and stimulated calcitonin, but thyroid C-cell hyperplasia was recently proved in the eldest. In this MEN 2A kindred the presence of such a characteristic hereditary itch in affected members may be considered as a phenotypic marker giving advance warning of medullary thyroid carcinoma.