ULTRASTRUCTURAL STUDIES ON PIGMENTED MACULES OF PEUTZ‐JEGHERS SYNDROME

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Abstract
Light and electron microscopic studies were carried out on pigmented macules on the lips, fingers and toes of the patients with Peutz‐Jeghers syndrome. Our studies indicated basal pigmentation was noticed in the basal cell layer of the epidermis, but no differences were recognized between the lesions and normal skin in either the number of melanocyte or the length of the dendrite of melanocyte in the lips. In fingers and toes, few melanin granules or melanosomes could be found in the basal cells. Numerous dendrites of melanocyte filled with melanin granules or melanosomes were seen in the intercellular spaces of the keratinocytes. The dendrites of melanocytes in the lesions were much longer and more branched than those in the normal skin. However, the population of melanocytes in the both areas was almost identical. Some melanosomes in the dendrites of the upper epidermis seemed to be degraded and exhibited a positive acid phosphatase reaction. We may assume that melanosome transfer from melanocytes or melanosome receptivity of the keratinocytes remarkably decreased in the lesions on the fingers and toes of Peutz‐Jeghers syndrome and then melanosomes had accumulated in the dendrites and some of them are being degraded.